Marantz 2500 From The Garbage! The Best Ever? Repairing & Restoring This Classic Vintage Receiver.

foreign my name's Chris and I repair my own audio equipment and I also show you how to repair yours so let's get started this Marantz 2500 was stuck in a closet in Texas just collecting dust never to make music again that's not happening on my watch join me as I take you through the repair restoration and the recovery of one of the most iconic receivers ever produced the Marantz 2500 [Music] not every piece of equipment that I have is in mint condition but I treat each of them with respect each of them can still continue on for decades even if they will never look like new pieces of equipment and I treat all of my equipment the same way this Moran's 2500 received the exact same treatment as if it came brand new out of the box it doesn't matter to me I'm going to treat it the same way I'm going to change out those electrolytic capacitors that need to be changed out after 45 years I'm going to clean it up a little bit I'll end up putting it into my system and listening to it and it just deserves that and I'm sure that even though this receiver will never look perfect it will sound Perfect by the time I'm done with it before I can listen to it I've got to get it up on the test bench but before I get it up on the test bench I'm going to have to go in there and restore it and you guys know me the first thing I'm going to do is take a look at this unit before I I powered it up so let's get started haven't already please subscribe I think the first thing you should do no matter what piece of vintage audio equipment that you obtain is take a look at it first just get it home put it somewhere and just take a look from the outside and see what issues you have take a look at the front take a look at the case take a look at the back and just see what you've got to start out with looking at the front of the Marantz 2500 I noticed that the balance knob is missing off of the balance control now the shaft is still there which is good I've got a 23.85 Marantz receiver where that shaft was broken off on the balance control and that's a bigger problem so that's one issue I see I'm just glad the shaft's there and just the Chrome knob is missing also over at the left by the oscilloscope display the vertical control is missing the Chrome cap off of the knob so those are the two main issues I see as far as the front goes of course as you can see the face plate itself is quite dirty and I'll get to that later on for right now I just need to figure out what to do about the balance control and also the vertical control on the oscilloscope what I'm going to use for knobs I ended up using the balance control knob from a Marantz 2265. it looks fine and the knob fit the shaft correctly for a replacement oscilloscope knob I got into my little pile of extra knobs and went ahead and made one myself from left to right what was left of the original oscilloscope vertical Center knob the knob I use is to make the new knob then the completed knob I removed the plastic from the replacement knob which made the knob more closely match the 2500s original chrome knob the new knob was slightly larger than the other Scopes knob so I just moved the level control to the vertical position I then installed the newly created knob on the Scopes level control shaft this just made the 2500 look more complete now the level knob is slightly larger than the other two but uh this 2500 looks so much better now you wouldn't know it if you didn't know it some of you may be thinking why are you showing me this cosmetic stuff let's get started on the troubleshooting of this 2500 this isn't very interesting the reason I show you this is that the Cosmetic parts of the Vintage audio equipment those are the ones that are very difficult to come by you can't get on mauser.com or digikey.com and order a part or get one from the OEM manufacturer like Marantz you can't get a hold of them and say could you send me a uh a knob for a balance control for 2500 they don't exist so I just wanted to show you different ways that you can go about making do with what you have you may have an old piece of equipment you may have some old knobs if you don't have any of that sometimes you can find these on eBay so usually you can find some sort of work around to find the Cosmetic parts that you may need for your particular unit like I did for this 2500 the same goes for the wood case that I was lucky enough to obtain with this unit this is an original Marantz 2500 wood case that was an option back in the day and you just have to make do with what you've got because there's no replacements for them at least original Replacements this unit came with its original wood case it's beat up there's no doubt about it it's scraped up at the corners they're broke off they're pushed in the grills at the top of the case are pushed in something heavy was sitting on them but you know that's okay with me I really don't care in the past years ago I might look at it and say oh no no no I've got to do something about this I've got to refinish this case but you know I don't think that's something I should do with this unit and with most units anymore I just don't I'll clean it up I'll make it look as good as I can because I think all these Nicks and scrapes and scratches and missing pieces of wood it tells a story of this unit and it tells a story of how durable these units are that they can be beat up but they can still function well and that's my main thing so I'm going to go ahead and clean up the case get the dirt get the grime get the dog and cat hair out of it that kind of thing but I'm not going to do anything else with it other than put a little bit of wood polish on it and make it look decent but not worry about it not looking perfect the rear panel of the branch 2500 looked fine 9. with the 2500 out of its wood case now it's time to take a little bit deeper look at it before I can go ahead and feel comfortable with powering it up and what I do at this point is to take the covers off and you want to take a good look inside the unit the best you can with your eyes just to make sure you don't see anything obvious that would prevent you from powering this unit up you don't know what's in there you open up the cover and there could be pieces all over the place who knows it could be burnt components you just don't know what you're going to see or maybe you see nothing I always follow the same routine for any piece of vintage audio equipment that I obtain that I know nothing about the first thing I see from the top is that the soft start relay is missing its plastic cover in addition that relay is loose in its housing you know these covers don't just fall off relays so this 2500 had been worked on at some point and probably abandoned there's a lot of dirt in the relay with a plastic case would normally protect it so this is probably many many years ago when this was work done um there's no case on the relay so there is no identification number the service manual along with the pin configuration should help me figure out what relay to replace it with as I researched this relay it made me think for a minute about all the times people will say to me you can't get the parts for this stuff anymore can you and 99 of the parts you can still get something like this relay and the cover being missing makes it more difficult but it's still possible to find the part that you need and I can't tell you how many times people have said they've taken their equipment to somebody and they say they just don't make the parts for it no more what they're really trying to tell you is they don't want to spend the time finding the parts and a lot of times that's because the people who want their equipment repaired don't want to pay them to find the parts working on vintage stereo equipment is no different than calling your electrician or calling your plumber you're going to shake their hand and you know they're going to charge you a hundred bucks it's just the way it is and same thing with vintage audio or anybody competent that's going to work on it you've got to expect when you take your piece of vintage audio equipment somewhere that they're going to have to spend quite a bit of time with it not just to diagnose the problem but to find out the parts that you need as you guys know a lot of my videos are geared toward folks that don't have a lot of experience so hopefully that helps you to be able to do your own work do your own troubleshooting spend your own time and not only do you save money but you'll learn something trying to learn something in the beginning is always difficult doesn't matter what it is whether it's vintage audio equipment or some other skill that you guys out there have once you practice you get better and better and before you know it you can Buzz right through a lot of these vintage audio products without a lot of difficulty I ordered the relay from digikey it's also available from Mauser and several other electronic supply companies here in the United States so it's readily available it cost me about twenty five dollars and I got it installed and now I'm ready to move on well as it turns out I didn't have to move very far I'm just to the left of the relay there's a power resistor the red wire you can see is stuck to the power resistor you know power resistors get very hot the insulation from The Wire just melded to the resistor you can almost bet you know this wasn't how it was obviously when it left the factory 40 years ago you know this is only 2500 I've worked on but it would not leave the factory um you know either it was restrained with a tie wrap or it was routed different something but they're not going to run a wires right up against a power resistor so the installation can melt so finding this relay issue along with the wire being melded up against the power resistor you can see how important it is just to look at a unit and you really didn't need any skill to find these issues other than to get the cover off and take a good look now these were the only two issues that I found but they're pretty big issues I would much rather have seen these problems before I plugged it in and turned it on what would have happened I don't know but I would just assume get those issues behind me before I even think about powering the unit up and talking about powering up this 2500 I'm a little bit apprehensive to do it even though I've worked on a lot of pieces of vintage audio equipment I always have a concern on any piece I know nothing about and I know nothing about this piece of equipment so the last thing I want to do is to blow up this 2500 in some manner that I could have prevented so for right now I know the face plates in really rough shape I know there's a lot of cleaning to be done so I'm still not going to power up this 2500 I'm going to go ahead and get the face plate off first and work on cleaning it up a little bit as you can tell this face Plate's rough it's got a lot of dirt a lot of probably either dog or cat hair and it's not unusual a lot of these pieces of equipment end up after a period of years they were used at one point and either the person who had it no longer wanted it or they gave it away or whatever happened and they just store it away and they get dirty this face plate is is in pretty rough shape as far as dirt and grime maybe a little nicotine stains that kind of thing but fortunately the stenciling looks pretty good it's not like all the lettering's gone so that makes me feel pretty good that I can probably get it cleaned up again from experience of other face plates and the first thing you want to do on any piece of an aluminum face plate anyway like the Marantz 2500 has is just use the least abrasive thing you can use at first which would be some warm water a little bit of dish soap some Q-tips a rag just start scrubbing that stuff off and see what you can get off and what you can if you can get it all off with that great if you can't then you got to move to something else after pulling the animal hair out of it and getting it cleaned up the best I could still down in that aluminum face plate there was crud that I could not get with soap and water and dish soap so what I use and I have used for many years is Mother's mag polish and it's always worked well for me but I'm not telling you to use it on your precious piece of equipment I would try it in a little spot and see how it works but it will get down in that aluminum face plate and pull all that crud out of there and make any aluminum face plate that I've worked on look better without damaging that stenciling without taking the lettering off now once again I'm not telling you to use it I'm telling you what I use and it's up to you to decide what to use on your piece of equipment now a quick word from our sponsor my rats one of the world's greatest names in Stereo Sound products Marantz stereo has a true musical sound with virtually no Distortion to come between you and the music [Music] um foreign music you enjoy enjoy it more on Morant stereo Marantz is music as you guys know that follow my videos I really enjoy the history of the Vintage audio equipment also I like finding these old commercials and this commercial happens to show the Marantz 2500 I didn't realize that at first until I went back and slowed it up and it's the 2500 I could see the oscilloscope I wasn't sure who was the 2500 or the 2600 and it was the 2500 and interesting enough they show all the components for the 2500. they show the internal parts of the 2500 including the power transformer the filter capacitors even that soft start relay I had to change out along with a power amplifier assemblies and their unique way of mounting the power transistors on the smaller finned heatsinks all right it's time to get back into the repair and restoration of this amazing Marantz 2500 stereo receiver one of the most iconic receivers ever built I worked on this face plate for some time to get it cleaned up and as I mentioned earlier I haven't even powered this unit up I went ahead and cleaned it up first this is a little bit unusual for me but this is just to show you there's no 100 percent correct way of working on Vintage audio equipment I felt like cleaning up the face plate because I was a little bit apprehensive about powering it up it was something I had to do anyway allows me some time to think about what I'm going to do when I do power it up because once again I want to be ultra careful with this particular unit and not have a surprise I've had surprises before I don't have them very often but I don't want to have one with this unit that's for sure so I went ahead and I cleaned it up and I knew I was going to have to put the face plate somewhere else for a period of time and whenever you're working on something cosmetic like this it could get scratched up or dirty 30. I I just wrap it in a little piece of bubble wrap and put it aside I don't put it on my workbench I just put it aside and that way it can't get hit by a soldering iron or just a screwdriver or something stupid to Mar it for no good reason so I got everything cleaned up and I went ahead and I removed the face plate and I put it in some bubble wrap and now I'm getting closer to powering up this Marantz 2500 it's always a good idea to power up any unknown piece of vintage audio equipment with a variac this way you can slowly increase the voltage instead of hitting it with that 120 volts all at once like we have here in the United States because you don't know how long it's been since this 2500's been powered up so it's always a good idea do you have to do that no but it just gives you a little better feeling that you can slowly Power It Up but if you have any issues hopefully you can find those before something bad happens here I just show my Marantz 10B tuner as I'm powering It Up For the First Time very slowly and but the procedure is the same it doesn't matter if it's a Marantz 10 beat tube tuner or if it's a Moran's 2500 receiver it's always a good idea to do that there are no issues on the initial power up but after I powered up the 2500 for the first time I noticed that none of the function indicator leads were fun you know we're working pick FM AM you know phono nothing it was dead that little indicator Board needs eight volts ac to operate I didn't have any any voltage to the board so there's a good reason why I wasn't working I found a broken wire that jumpers the eight volts ac from the dial lamp board to the function indicator via you know like I say just via wire so I just jumpered it and I figured well that should do it well I had eight volts still didn't work so anyway after troubleshooting I found a shorter diode on the uh indicator board and after after fixing the wire and putting in a new diode gee we had you know the function board worked but this is how these things are anything that's 40 years old don't care if it's an old car an old piece of stereo equipment you're probably going to have multiple problems before I show you everything that I had to do to get this Marantz 2500 up and running I want to talk to you a little bit about the Marantz 2500 first of all I want to bring up just the one Achilles heel with the Marantz 2500 and the Marantz 2600 and that's the power transformer there appears to be over the years several of them that have failed I say several of them what does that mean I don't really know because not a whole lot of these units were manufactured pictured the 2500 there was around 1700 of them manufactured total the 2600 there was under a thousand so there's not many of them manufactured there's been enough people who own the two receivers that have reported problems to make you think there may be an issue with some of them now I have never had an issue with mine but doesn't mean I'm not gonna have one but I've got the original Transformer that came from morants in 1977 and as I said there was only about Seventeen hundred of these units produced from 1977 to 1979. so if you have an issue with your power transformer it's a big deal it's going to be an expensive fix there actually is an aftermarket power transformer that's available for these units for around 1200 US Dollars that's quite a bit and that's just for the part and then you've got to do the work to put it in or pay somebody to put it in so it's something you just assume soon avoid so that's one thing to keep in mind if you ever run upon one of these units that make sure the power transformer is good or don't offer a whole lot of money for it normally I would just say well if a unit doesn't power up don't worry about it it's not going to be the Transformer I've never had a Transformer bad in any of my equipment ever but in this unit if I Came Upon one that wouldn't power up that's the first thing I'm thinking about I'm going to make sure if that's the problem then I'm going to get the unit for a a very reasonable price so other than the power transformer all the other electronic parts are still available they may not be the exact same part many times the modern equivalent is superior to the capacitor or the transistor or whatever it is that you're attempting to replace in your vintage piece of audio equipment cosmetic items are more difficult to obtain because you can't go to Mauser or digikey or some other part house and Order knobs or a face plate for Marantz 2500 you have to either scavenge them off a donor unit or you have to find something that will work and usually you can a lot of times the knobs that were used were used for several years on several different models and that's usually something that you can get around whether you get on eBay and find some used knobs or you've got another piece of equipment that you can scavenge off of to replace some knobs that maybe you're missing now the face Plate's a different story that's unique to that particular model unit and that's much more difficult if you need a face plate but fortunately most of the time the face plates are still intact on these vintage units all right now to talk a little bit about the specifications of this Marantz 2500 it produces 250 watts per channel into 8 Ohms a mass of 330 watts per channel into four ohms with a total harmonic Distortion rating of 0.05 percent and this was a 1977 and I want to talk a little bit about how receivers got to this point in 1977 because in 1974 just three years before the highest rated receiver was 100 watts per Channel and suddenly three years later we're at 250 watts per Channel a huge increase 1974 was a major year for specification changes the FTC came out with new parameters of how you rate audio amplifiers for the commercial market and this put the playing field level for everybody before then you might have a 50 watt per channel uh amplifier that somebody says is 50 Watts but your 5 watt amplifier without perform it because they would have some bogus music power rating or something else so the FTC to level this out and to stop all the BS from happening with the manufacturers they made everybody perform under the exact same parameters so with the new Federal Trade Commission rules in place the Pioneer SX 1010 was the first audio receiver that was rated at a hundred Watts RMS per channel that same year Marantz with its model 2325 topped the Pioneer with 125 watts per channel so this is kind of the start 74 of the power Wars of the receiver power Wars both Pioneer and Marantz got off first with this before Sansui or Kenwood or many of the other other manufacturers who came along in the next few years to join into the receiver power War era after seeing what Pioneer and Marantz did in 1974 the other manufacturers started to come back in 1975 with their own receivers that were rated at 100 Watts or more per Channel RMS one was the Sansui 1990 and also Kenwood came out with the KR 9400 so it's 1976 started Pioneer came out with the sx-1250 well now the sx1250 was going to bring to the table 160 watts per Channel as if to say here go ahead guys beat this one and along with the Pioneer sx1250 came a new company under the scene of the receiver Wars the Technics sa 5760 again a monster receiver 165 watts per Channel and other ones like the Rotel RX 1603 with a 180 watts per Channel showed up in 1976. so everybody was getting in on this power Wars at this point so 1977 rolls around and Yamaha comes out with their own monster receiver the cr-3020 at 160 watts per Channel Kenwood comes out with their KR 9600 again 160 watts per Channel then a name most people don't think of when it comes to audio back then or now Hitachi with a 200 watt per Channel receiver Sr 2004 and then came the Marines 2500 at a unbelievable 250 watts per channel into 8 ohms and 330 watts per channel into 4 Ohms and this is 1977. this again is only three years out from when the receiver power War started so there was massive jumps in power through just a very short period of time but now it's been about 50 years since this receiver has been manufactured so I knew this was going to be a big project and I was going to go in there and not only have to repair but also restore this Marantz 2500 this is Marantz 2500 is much lighter than many of the high-powered receivers that were built during this time frame and most of that has to do with the small heatsink assemblies that they used in the 2500 along with a fan to help dissipate the heat so a lot of the weight was reduced there this unit only weighs about 60 pounds which is still a lot but it's not a hundred pounds the engineering of the 2500 was all top-notch and I'm going to show you ahead how I went ahead disassembled this entire unit even has its original Power transistors that left Japan almost 50 years ago I'm going to take it up on the bench after I get done repairing and restoring this unit making sure it operates to its original specifications as close as it can and then I'm going to put it into my music system and I'm going to do what it was made to do and that's play music so let's get back to it I'm going to get back and start showing you the restoration nation of this amazing Marantz 2500 as I mentioned earlier the Transformer can be a possible issue in some Marantz 2500s but another issue I had repairing and restoring this 2500 was it was difficult for me to work on now remember I'm not a professional this is the first 2500 I've ever worked on I'm strictly a hobbyist I've taken quite a few of these apart and put them back together but I'm by no means a professional so for someone else maybe that knows what they're doing better this would be a piece of cake but for me this 2500 even though it wasn't the biggest the heaviest the most packed in piece of equipment I've ever worked on everything seemed to be difficult or at least a lot of it did and a lot of that had to do with the connectors on some of the assemblies they had regular pin connectors you could remove the connector and that was is easy enough on others they were soldered on on other assemblies it was a combination of both and it seemed like no matter what I undid I had to undo something else to get to it and it was a little bit odd for me because normally the progression of these pieces of equipment you take one thing out and you take another thing loose and you can kind of see how they come apart once you have some experience with them with this one it wasn't that way so I have to say that the mechanical engineer or Engineers which it almost appears like you had two or three people or two or three groups that were mechanically putting this unit together I I'm not sure if they couldn't have done a little bit better job and I think a lot of that just has to do with giving me a little more slack in in the wiring there's not a lot of slack so you loosen something and all of a sudden you start to try to remove it and you've only got an inch or two and you're wondering what the heck is holding you up and you think well it's this connector so you move this connector which is easy enough you remove a connector off a board and you got a little more play then you take off another connector another connector a little more play but you still feel like you're fighting something and before you know it you're having to loosen a Cable Bundle in another section of the receiver to give you enough slack any of you guys looking to get a Marantz 2500 or maybe a have one I just wanted to give you a heads up about what I found when I started tearing into this unit just a little bit more difficult to get around than some not that you can't do it but it's just a little bit more crammed in there and a little bit more in my opinion haphazard than maybe it needs to be and you may notice too in a lot of these pictures I've marked the cables you can do that in any manner you want I also take pictures obviously because I do these videos so I take pictures of what I'm doing but I also Mark these cables and even with arrows up because even the cabling unlike a lot of vintage audio equipment many of these cables are not keyed meaning you can put them in wrong you can put them into the wrong connector you can put them in upside down a lot of pieces of equipment you can't do that they key them in one way or another they either have an extra pin or the the connector is keyed in a way where you can't put it in upside down it's practically impossible if you do then you're forcing it in this unit's case you can put them in upside down if you're not careful so as I mentioned this was a lot of wiring that's just kind of all over the place and so I just went ahead and marked them up marked which table it was and which way it was in which direction because once I started unhooking this stuff and loosening stuff they get all orientated different in most units I don't have to do this I wouldn't even think about doing this I wouldn't have to worry am I going to be able to get it back together again but it's another precaution I guess I've learned from making mistakes in the past that it's just better take a little bit extra time mark them if you need to which I felt I needed to and you'll end up having a good result in the end before I can work on this Marantz 2500 any further before I could restore or repair it and the same with you guys whether you have a Marantz 2500 or another piece of equipment that you want to repair or restore you need the documentation that will allow you to do that whether it's a repair or a restoration hi-fiengine.com is the resource to get owner's manuals service manuals old brochures just about any type of documentation that you would need to either restore or repair vintage audio equipment all you've got to do is go to hi-fiengine.com open up a user account and you're ready to download there's no charge and from my experience they have 99 percent of the documentation I've Ever Needed for any piece of vintage audio equipment the most important document is that service manual for whatever piece of equipment you're working on without a service manual you're not going to have a chance to be able to repair or restore this equipment it doesn't matter who you are it doesn't matter if you're inexperienced or your experience you need the service manual but not only the service manuals are on there as I indicated there's the original owner's manuals are on there and that's really nice to have because many of us don't have the original manuals with our equipment they've gotten thrown away over the years and they're just not there and also I mentioned the brochures these are the same brochures that back in the day when I went to my local stereo shop and I'm there looking around I walk out of the store if I don't purchase anything I walk out of the store at least with some brochures and and they try to talk me into coming back and buying the stuff so as I said Hi-Fi engines a great resource for anybody who's into vintage audio earlier in the video I mentioned that most of the parts are available for any piece of vintage audio equipment but I really didn't go into any extra details about that like well where do you get them then Chris so let me go ahead here for just a minute and let you know where you can find parts for not only this Moran's 2500 for any piece of vintage audio equipment that you may have Moser electronics and digikey electronics are where I feel you should buy most of your parts from they'll have 95 percent of the components that you need to keep your vintage audio equipment running or to restore your vintage audio equipment now things like cosmetic pieces let's say you're missing a volume control on your receiver you're not finding it here you're going to have to go to eBay to get something like that transistors capacitors resistors those type of components a lot of people just think they're going to go to these sites and just find their parts it's going to take you some time and it's really not that difficult to find the parts but there's a lot of choices and you've got to know which ones to use and that's the difficult part so I would suggest that you go to some of these audio Forums on the Internet or just do a general search on Google like Pioneer SX 1980 restoration or something like that and you'll find some long articles on what people have done what parts they've used Etc and that'll help you help you find what you need from time to time I'll get asked for my build list for a project I work on so many different units that I just keep a stack of parts and normally the only thing I won't have are those filter capacitors anyway I don't have a bunch of those sitting around but the rest of the components I order in quantities of 10 25 maybe even a hundred at a time you can purchase these quite a bit cheaper if you buy them in bulk from both Mauser and digikey and it's just so convenient to just start a project and have all the parts available you guys that follow my videos know why I need all these parts because I go in and I restore every old piece of equipment that I have I'm a firm believer in getting those old electrolytic capacitors out getting those other known semiconductors out of there that are known to be bad Through The Years there's several transistors that are bad if you find them you got to get rid of them or they're going to cause you trouble there's a few diodes but the main thing is those electrolytic capacitors there are all going to fail and it's not me saying that it's the manufacturers of those capacitors to say that and I just ask you all again to please do your research in today's world there's really no excuse for you not knowing the truth about electrolytic capacitors just Google electrolytic capacitor lifespan and start reading and you'll find all the manufacturers websites talking about it you'll find Engineers talking about it every single electrolytic capacitor no matter it's quality it's going to fail someday you're probably thinking well yeah they're all going to fail everything's going to fail eventually but if you guys don't want to do the research I understand I've done a little bit of it I'm no expert as you guys can tell I'm not real bright and I'm a hobbyist who works on Vintage audio equipment but I can tell you a little bit about them and the reason that they fail is because of a slow evaporation of the electrolyte that's in these capacitors two main issues cause that electrolyte to start to evaporate great and that's a lot of time and that's a lot of heat there it is in a nutshell if you've got an electrolytic capacitor that's been in a very hot environment for a very long time you've got a better chance of it failing but generally and again to just come down to a conclusion after about 20 years in a normal environment you can expect your electrolytic capacitor to operate properly within its specifications and not fail on you maybe you'll get really lucky and then we'll go 30 or 40. it certainly can happen depending on the capacitor but keep in mind every failure is not an explosion every failure is not my receiver won't power up many times these fail slowly over time they don't fail spectacularly and so you may believe that your piece of vintage audio equipment's working great if it's 30 40 50 years old and hasn't had its electrolytic capacitors changed out it's very unlike likely it's operating like it did when it was new but as I mentioned earlier this is just something you all got to decide on your own I restore my equipment you may not want to do it to yours am I right or you wrong no you do what you want to do with your equipment I do what I want to do with my equipment so now I'm going to start the restoration process on this Marantz 2500 and as I've just indicated those electro electric capacitors that are 50 years old they're going to be gone there's also a few transistors a few diodes that are known troublemakers that will also have to be replaced but for the most part this is all about those electrolytic capacitors and getting new fresh ones in there so that this Marantz 2500 can go for another 50 years or it'll probably go longer than that I would not be surprised to see this receiver still operating 100 years from now although the service manual has a parts list the only real way to determine what parts that you need for a restoration is to look at the parts that are in the unit that you have 95 of the time the service manual is probably going to be correct but when you're replacing a hundred parts let's say in a restoration something like this one inevitably you're going to miss one or two of them or the service manual that you have is not accurate for the model that you have it was built at a different point in time in the production process and it's not accurate so just take a look at what you have in your particular unit then go ahead and order for Mauser digit key and it'll save you a lot of headaches down the road so I'm going to show a few details doing this Marantz 2500 that I don't normally show and this will relate to any piece of vintage audio equipment that you you may be restoring so first of all I want to show you here in the picture what you're looking at and this is the pre-amp and tone amp circuit board mounted to that is the balance control along with the filter amp board so there's really three different assemblies that you're looking at here at the picture now over on the chassis side you can see where this assembly was removed and I was able to undo the cables as I said a little bit of a pain to get it out but now I have it out in my hand and I'm able to deal with it much easier than when it was down in the chassis now here's a picture of the same assemblies in the Moran's 2500 but they're still inside the chassis both the pre and the tone amp circuit board along with the balance control and the filter amp board so hopefully this helps you understand a little bit looking at your unit it doesn't have to be a Marantz 2500 doesn't that Marines at all if you've got a receiver from this era anywhere in the 70s 80s it's built in a very similar manner so you look over there at your Onkyo or your Sansui or your Pioneer your Kenwood your Yamaha they're all built in a similar manner so now I've separated the balance control in the filter amp board from the preamp circuit board and now I'm able to get to all of the controls on the preamp board easily as well as being able to get to the connector pins on the filter amp board so though I was complaining earlier about the cabling right now I'm saying hey this is pretty nice because then I've got these assemblies just right out here in my hand and as you can see it's going to be much easier for me to clean the controls and replace components all of you guys have either had or heard of having a unit that's sound comes and goes the left Channel's scratchy then it comes back you move this switch or you move the balance control it comes it goes and almost always has something to do with a dirty control somewhere in the unit and after all these years these units that are 30 40 50 60 years old they all need to have their controls cleaned and I happen to use deoxin and I'd like to talk to you a little bit about cleaning the controls I just wanted to talk a minute about the products I use to clean the pots the switches and the various different moving parts and a piece of vintage audio equipment now I use deoxit products it's easy for you guys to go out there and do your own research these aren't the only cleaning products available I've used them for a lot of years I've never had an issue some people will say some of these don't work or they don't work properly or whatever I'm not a chemist I'm not an expert on how one particular lubricant may damage a piece of carbon or may damage a piece of plastic or what have you but I just want to say from practical experience that these products have worked for me so in this 2500 I'll use the deoxin spray for the potentiometers and I'll use the liquid deoxite for things like pins where you don't need a spray to go all over the place you just need a little bit of deoxin on a pin and usually use an acute tip Works real well and you can just wipe the pins that way and that just works out better makes a lot less of a mess the push button switches in the 2500 it's critical that you clean those well and not only in a 2500 but any piece of vintage audio equipment they are just known troublemakers and they cause all kinds of intermittent issues that take you forever to try to figure out what's going on so just while you have a unit apart like I've got this 2500 apart just take your time and clean those well with some deoxin or whatever your favorite cleaning spray is taking this thing apart is really not that difficult but keep the screws the washers Etc in a way that makes sense to you me you know I kind of line them up I kind of think ahead where does this go back and I don't get too far ahead of myself so I'm not you know at the end thinking where does all this stuff go the reason I bring up the Fasteners things like the screws the washers Etc and making sure you kind of keep track of them I can't tell you how many pieces of equipment I've worked on where screws are missing washers are missing some of the screws are missing some of the washers are missing you know and I know what happened somebody was working on it they're taking it apart they're putting the washers here they're putting the screws there they're thinking I know where these go I'll figure it out well they get done and they didn't figure it out all right I've got the pre and tone amp circuit board finished up along with the filter amp board and so now I'm going to move on to the next boards and these are the phone no and selector switchboard and the tape and scope display switchboard the phono and the mode selector switchboard is located at the bottom left of the chassis in the model 2500 here you can see in this picture I have the chassis sitting on its side and I've got that board already removed and just above that board you can see the tape and scope display switchboard which I haven't removed yet if you take a look at this picture down toward the bottom this is the phono and selector board you can see there's 10 maybe a dozen wires that are wire wrapped directly onto this board it also had connectors several connectors hooked to it and once again those were easy enough to pull off but I do not want to unwrap every single one of these wires and then solder them back on again so fortunately I figured out a way to get enough room to work on the board I wish I had a little bit more but that's enough for me to get in there and change out the components I need to change this is what I was talking about earlier where the unit is not all that easy to work on in my opinion can you work on it yeah am I working on it yes I am but have been nice if all those were plug-in connectors and I could just unplug it and put it on the bench and work on it a lot easier but that's not the way this one is I've removed the tape and scope display board had no issue getting that out came right out and you may be able to see in this picture how there's connectors and I just had to unplug connectors from those pins and out it came unlike the photo board I just showed you so I'm going to go ahead and change the only electrolytic that's on this board and do that and I'm going to clean again these push button switches they are problematic any of these switches can cause you an audio issue down the road so last thing I want to do is have this all tore apart get it back together and then have to tear it apart again so I'm making some progress here on these last four assemblies that I've shown you I've gone ahead and I've replaced those 50 year old electrolytic capacitors that needed to go I also I'll inspect the artwork and just take a look at things and make sure I don't see anything obvious while I have these assemblies out of the chassis and people will ask me well what electrolytic capacitor should I use what brand should I use first of all brand wise just use a quality name if you like Panasonic great use Panasonic if you like nishikan use nishikan if you like Elna use Elna Etc just use a name brand capacitor manufacturer and your restoration will turn out great now as far as the values go of capacitors it goes without saying you should use what you took out so if you took out 100 microfarad 100 volt capacitor you should replace it with that or a minimum of that voltage a lot of times I'll have maybe a 10 volt capacitor and I'll move it up to a 25 volt capacitor but I'll always keep its capacitance value the same so that you shouldn't change you can bump up the voltages if you'd like to and it might be a good idea too doesn't hurt because the higher voltage capacitors and whatever capacitance you use in they're just a few pennies more another item that I use a lot is my desoldering tool and I've mentioned this before in videos but if you're going to do a big project like this or work on this equipment often a desoldering tool is as far as I'm concerned is a must it makes it so much easier to do and you have so much less risk of damaging any of these boards by using this gun it'll Heap those pins right up and it'll make a somewhat difficult job pretty easy as I've mentioned through this video there's a number of points in the 2500 where they've soldered wires directly to pins now this picture shows the speaker switch assemblies speaker one and speaker two now I'm just showing this as an example of take a look at the soldering points while you have this all apart you've got to remember you're bending the stuff back and forth several times you're putting some stress on it it's just a good time to find a problem before you put it back together and find out you got a problem so normally I would have not worked on as many sections of a project before I put it back together to try it than I've done here on this 2500 and that's because as I've been saying it's been a little bit more difficult to get apart a little bit more difficult to get back together and then I have to take it all back apart again so while I had it apart I just kept taking it apart and so I've worked on a lot of different assemblies as I've shown you at this point I am going to put it back together because I shouldn't have to get into this area again from underneath the chassis here and to get to the pre and the tone amp boards and the filter amp and the phono amp selector switches and and all the different boards that I went through I should be able to put that back together and I don't think I'll have to get back down here again unless I find a problem after I get it back together that I caused when I was working on it and that does happen it happens not all the time it happens a little less frequently than it used to when I first started out I'm a little bit more careful then just give the 2500 a quick test make sure I've got both channels the 2500 checked out just fine so now I'll continue on with the repair and restoration next I'm going to work on the audio muting board on this Marantz 2500 and this board is situated if you look from the top with the cover off on the right hand side toward the center of the chassis and on the small assembly there's an Omron speaker relay and that's been in there nearly 50 years now is it still operating it appears to be in my checking so far everything seems to operate fine but I'm going to change it out it's only about a fifteen dollar part it's been in there nearly 50 years why leave it in there makes no sense to me somebody else might leave it and say don't worry about it you know if it fails I'll replace it well it's just not the way I do things if I'm going to go in here and restore it I'm going to go ahead and do it correctly and in my opinion correctly is getting a new relay and the great thing is the relay is still available you can order it from either Mauser digikey easy to get and there's really no reason not to change it out I'm going to go ahead and change just the one electrolytic capacitor that's on this audio muting board and I'm using 105 degree Centigrade rated capacitors not only in the single capacitor but in all the capacitors in this project it just gives you a little bit more more of a cushion after whining about some of the other assemblies and how they were difficult to work on this guy here was a piece of cake just held in with a couple screws so there was no issues with this audio muting board whatsoever as far as getting it in or out of the chassis the next board I'm going to go after is the regulated power supply and in any piece of vintage audio equipment this is probably one of the leading causes of problems in the older equipment because the power supplies and these pieces of equipment generally run quite warm and they're under a lot of stress and as I indicated earlier heat and time heat and time is what destroys components and power supplies generally have a lot of heat and of course after 50 years or so there's been a lot of time to go by so that area of any piece of vintage audio equipment doesn't have to be like the submarans 2500 usually is a spot that needs attention as I mentioned earlier take a bunch of pictures write down on a piece of paper Mark the cables in some manner though so you can get this back together before you start unhooking it the last spot you want to hook up a cable incorrectly is in your power supply so the main thing is before you start to disassemble any part of your vintage audio equipment take pictures write down on a piece of paper where they go Mark the cables in some manner that you understand where they go because this is not an area of any piece of vintage audio equipment that's going to tolerate something hooked up incorrectly we're Marine it's mounted this regulated power supply is a great spot it's at the top of the chassis the heat can dissipate off of this assembly and out through the case easily unlike my Pioneer sx1980 where the regulated power supply for that monster receiver is mounted at the bottom of the chassis and Pioneer SX 1980s are known to have issues with their power supplies and that's one of the main reasons why because in Pioneer's case they decided to put it at the bottom of the chassis and the heat just cannot get out of there and it bakes itself over a period of years now in this 2500 though the power supplies in an ideal position at the top of the chassis and so that heat can rise and get out of the chassis easily so another thing I like about this power supply is that it easily comes out of the chassis all all the wiring was connectors so I just had to pull the connectors and loosen the board and I've got it right in front of me so it's going to make it a piece of cake to get in there and change out those old electrolytic capacitors and in my case I'm using nishikan PW series capacitors and this power supply as I indicated earlier that's not saying there aren't many other ones you could use that would work just as well but that's what I'm using in this particular power supply I'm also changing out the transistor regulators and again saying well why are you doing that well there's nothing wrong with the power supply that I know of other than it's almost 50 years old and while I'm in here for just a few dollars I can get some Modern equivalent Regulators in my case I'm using on semi mje15032 regulator transistors they got a great reputation there's a very good chance they're going to last forever in this unit and while I'm in there I'm going to do that and at the same time I'll change out the transistor insulator I'll put a new insulator in there and I'll also clean up the heat sink and I'll apply some new thermal compound again is any of this a hundred percent necessary maybe not but it's the way I do things it's the way I restore my equipment I'm going to do everything I can possibly do to make this unit reliable for the next 50 years some of you guys may have noticed in this picture that some of these capacitors are rated up to 350 volts but that's all about the oscilloscope nothing else so the only reason these capacitors are rated as high as they are some of them is for the oscilloscope which is an unusual feature in this Marantz 2500 whenever I've done some work like on this power supply assembly where I've changed inched out several capacitors along with some transistors I take a look at my work before I reinstall it sometimes you find issues sometimes I have a solder joint that I didn't do well sometimes I find an issue I could have found just by taking a look everything looked good so I went ahead and reinstalled the power supply back into the chassis and now all I have to do is Hook the cables back up and give it a try I powered the 2500 back up no issues at all so now I'll continue on so I've made a lot of progress with this restoration I'm getting closer to being able to show you how this Marantz performs on the test bench along with some surprises as big as this one now did you hear that but first I want to talk a little bit more about the history of the Marantz Corporation Soul Marans had a dream to create the highest quality audio products and that is exactly what he did Soul B Marantz perhaps the man and most responsible for the birth of a high-end audio industry was born the oldest of three children on July 7 1911 in New York City he received art training with courses at Pratt Institute in Brooklyn after his formal training he became a commercial artist serving clients such as Hayes and General Electric he met his future wife Gene Dickey in New York City at a St Patrick's Day party in 1939 Gene wants to play a pivotal role in bringing the name Marantz to the Public's attention in years to come Seoul joined the Army transportation service in the spring of 1943 as a civilian employee during his employment with the Army transportation services Seoul earned his GED and though he was technically a civilian Rose to a rank of major after the war soul and Gene lived in Woodside a suburb in the borough of Queens New York City and later moved to Kew Gardens another Queen's neighborhood Soul marans's musical interest blossomed in the late 1940s and early 1950s the arrival of the first long playing micro Groove record spinning at 33 and a third Revolutions in 1948 and general post-war Prosperity contributed to the rising interest in High Fidelity equipment among many other companies Macintosh Fisher and H.H Scott they began to manufacture components Soul Marans however was not satisfied with the commercially available components of his day and he began to build his own his wife's proficiency with Calculus proved invaluable to Seoul as he readied the audio consulate his first product Jean's ability at solving complex equations allowed her to calculate the proper values for many of its internal circuit components in the early 1950s Sydney Smith came on board as an engineer at Marantz and would be responsible for a large part of morantz's success in the early years of audio including the 10B tuner it's interesting that neither he or Soul Marans had electrical engineering degrees Mr marantz's formal education was in graphic arts He was largely self-taught in electronics Mr Smith had some radar training in World War II that was how he was exposed to electronics interesting also a dick Sakura another person credited with much of the RF design of the 10B and also being considered as one of the greats when it comes to tuner design for his work at his own company years later didn't have any either but he did have RF experience as he worked at Pilot radio before he came to Marantz there were other people like Mitch Cotter hired as a Consulting engineer for the 10B project but the main core of the 10B Engineering Group were not formally educated in electronics that was that was something that could happen in the 1950s or 1960s but no way it would happen in today's world I obtained the information about the Marantz Corporation and the Moran's 10B tuner that you just heard from two different Publications on the internet my presentation was only a small part of the information that's available one of the Publications is vacuum tube Valley issue number five that was published in the fall of 1996. this publication can be found by searching worldradiohistory.com in that issue many of the people that were part of the original Moran's 10B project were interviewed each spoke in their own words about their contribution as well as others who contributed to the 10bs tuners development it really is a great read for those of you who want to hear the 10b's real story and not a load of BS that you so often find in the forums on the internet the other publication can be found at audiohistory.com here the family of Seoul morants is interviewed including his daughter June there's no better source of information about a person than hearing it from other family members again a great read for anybody looking for genuine and accurate information about Mr Moran's and his company as I mentioned I find the company's history very interesting and I talked a little bit here about my 10B tuner because this was the product that really caused Moran's to sell the company to Super scope in 1964. when this 10B tuner came out in 1963 it retailed for 650 dollars that's a crazy amount of money it's still a decent amount of money in today's world 650 dollars but back then you could get yourself a real nice car for that as Mr Morant sold his company in 64 to Super scope he really didn't have anything to do with the Marantz 2500 in the late 70s but I do find it interesting they both had oscilloscopes because oscilloscopes have never been something that was common in commercial audio equipment now I'm going to get back to the restoration of this Marantz 2500 and now I'm going to go after the peak indicator and the soft start circuit board and that sits on the right side of the chassis near the rear so once again take some pictures or Mark the connectors before you remove them from the board so you can get it back together again if there's any question this board's just like the other boards it's got those old electrolytic capacitors in there that I'm going to change out and in this board's case it's got a diode that over the years is a known Troublemaker not just some variance 2500 or not just the Marantz products in general but in vintage audio equipment and this diode was used in many other brands Pioneer Sansui Kenwood Etc so if you see these diodes they need to be changed out these diodes have a forward voltage drop that's between 1.25 and 1.35 volts so what you can use most of the time as a replacement seeing that you cannot get the exact replacement anymore is to do what I did and I used two 1n 4148 diodes in series and you just go ahead put those in series put them in as a replacement and you'll probably never have an issue with these diodes ever again after getting the components changed out I went ahead just like I did on the other assemblies hooked it back up and gave it a try everything seemed to be working fine so on go now I'm going to work on the main amp section of this Marantz 2500 and this consists of two individual boards one's the Left Channel one's the right Channel and they're each mounted on to the heatsink tunnel and these are a little bit harder to see the right channel is pretty easy to see here with the case off you can see it's mounted here on the side now the left channel is kind of down in the chassis and you can't see it very well while it's still mounted in the chassis and you can see it here going down the left side of this tunnel here's a picture looking down from the top of the Marantz 2500 and you can see toward the back of this picture this heatsink tunnel and a little bit more of a close-up you can see the heat sinks that the power transistors are hooked to inside side of this tunnel now it goes without saying make sure you take pictures before you unhook the assembly make sure that you write down on a piece of paper or that you mark the cables before you unhook this assembly and once you do that this is another one of those assemblies from the top that just pulls straight on out there's just several screws that you have to undo and once those screws are removed the whole assembly comes out the heat sink tunnel along with the left and right Power Amp assemblies with the tunnel assembly removed if you look down from the top you can see where the power transistors are all mounted inside of this tunnel so what you have is the power transistors on the inside of this tunnel hooked to their heat sinks and then you have the left and right channel Power Amp assemblies mounted to the outside of this tunnel in this picture you can see the fan man that was mounted to the power transistor tunnel and this is necessary in this unit because the power transistors are not mounted onto big large heat sinks like they are in some big receivers of this era so this fan was necessary to keep them cool and whenever you have a fan and any piece of equipment dust and dirt is just going to collect how that happens I'm not exactly sure you think moving air all the time that wouldn't happen but just think your ceiling fan in your house turn it off and look at all the dirt and dust that collects on it with air moving you wouldn't think that would happen but it surely does both Power Amp assemblies come off of this heat sink tunnel easily again it was great all I had to do is undo a few screws and it pulls right off of three different connectors so it was a piece of cake and again I was able to place the board right in front of me he makes it so much easier to work on and I can go in there and change out those old electrolytic capacitors and again as I reminded you earlier pick the ones that you want just pick a good quality capacitor and it's going to be better than those 50 year old ones that are in your piece of image audio equipment what I'm also going to do is I'm going to take the tunnel apart so I can access the power transistors where they're mounted and after decades as I indicated before showing you some of those pictures a lot of dirt and dust is collected again there's a fan hook to this and you think the fan would keep stuff moving but for some reason they always collect dust in different places so what I'm going to do is go ahead and get all those Decades of dirt and dust cleaned up these are the original Power transistors that left Japan almost 50 years ago and so get in there clean those up and have them run cool so they'll hopefully run for another 50 years and the same thing with the heat sinks themselves there's just Decades of crud on them that need to be cleaned up and along with that is the heat sink tunnel itself this picture shows where the power transistors are mounted against the heat sink get in there and clean all that stuff up one thing about this unit which is a little bit unusual is that the power transistors are not mounted in sockets many times you just have to loosen a couple screws and they'll come right on out for you in this unit it's not that way you have to unsolder the base and the emitter to be able to remove these power transistors and this is where that hakko desoldering tool I can't tell you how much of a help it is with this particular issue because these solder points are pretty big and you could use solder Wick or you could try to remove it in some other manner but boy what a pain in the butt it would be and I'm so glad I have the desoldering tool to help me with that as I mentioned these are the original Power transistors that came with this Marantz 2500 almost 50 years ago so I want to do everything I can to make sure that these continue to operate properly and so I'll go in there and I'll clean up the cases as most of you know when you're looking at a power transistor really what I'm holding here in my hand is the case the transistor is inside this case but I'll clean that case up so it can transmit heat better and what I'll use is just some alcohol all get that old thermal compound off there and make them look pretty much just like brand new what I'll do is install new Mica insulators these are just a few pennies a piece they don't cost very much some new thermal compound I'll apply that to them and these will be good to go for another 50 years so you can see how nice these heat sinks clean up this was just with some soap and water nothing more than that so now with everything cleaned up I can start to reassemble everything back into the tunnel I can put those power transistors as well as the heat sinks back in along with a new Mica insulators and the new thermal compound what I also did at the same time that I receded the power transistors what I did is I replaced the driver transistors that are also mounted in this tunnel are the old ones working yes they are but they've been in there a long time and I didn't want to have to get back in there down the line so fortunately in today's world there's some great equivalent transistors that work wonderfully for these drivers and these are the on semi mje 15032 and 15033 drivers and they work Wonderful in any vintage piece of equipment so I went ahead and I changed those out again new Mica insulators new thermal compound so now as I mentioned now it's putting it back together and it takes a little bit of time to get all 16 back in there and actually you do one channel at a time here I'm showing like one of them completed this is just one half of the assembly and there's another half that is shown here in this picture here that I haven't started yet you can see it's all dirty on the right hand side and on the left hand side it looks all cleaned up because it is so I've got to go ahead I've got eight out of the 16 power transistors receded and the tunnel cleaned up and the drivers changed out and I've just got to do it on the other side and I'll go ahead and do that and of course on that other side you've got the other power amplifier assembly that I've got to get in there and change out the old electrolytic capacitors and go in and clean up the heat sinks and just like I did on the other side so it's just to I just have to go in and repeat myself when I first took this assembly apart I mentioned connectors how the power amplifiers assemblies were just plugged in to the tunnel assembly which was really nice for working on and changing components but it also gives me an opportunity to clean the pins with the oxid so I'm going to go ahead and do that and then I finished both assemblies and I showed them here they're all ready to go I'll put them back together and most likely these will go another 50 years and I think it's just great to be able to have the original Power transistors from 50 years ago still operating so I'm going to go ahead and get this back together I've got everything reassembled I went ahead and attached the two pieces of the tunnel back together I also attach the left and the right power amplifier boards to the tunnel so it's all back together and it's all ready to put back in the chassis while it was out of the chassis of course I cleaned that up I'll probably never get in there again so I took a rag and made sure I wiped everything up down in there pretty good so I think we're ready to go I think I'm ready to give it a shot and let's see if it's still working I hooked the tunnel assembly back back up into the chassis of the 2500 using the pictures I had taken before I'd taken it apart and I went ahead and I powered it up and everything seemed to be fine I just let it sit there for a few minutes I made sure both the left and the right channels were working because that's what I'd worked on I'd worked on an assembly that could affect either both or one or the other channels so I went ahead and just let it sit there on the bench for a little bit and made sure everything was working so it was so now I'll continue on I knew from the initial power up the 2500 that the fan was very loud I didn't know how loud it was supposed to be but I did know it was louder than it should be and I knew at some point I'd have to take care of that so I just figured out I've got other things to do and I'll get to it well I've just about got to that point where I've got to do something with the fan and what I decided to do is just replace it I thought about taking it out clean cleaning it up taking it apart and again I came back to the it's decades old why do that why not just replace it with a new one so that's what I went ahead and did and the new one is much quieter than the old one that was in there another issue I had initially when I first powered up this 2500 I had a hum from the phono section as I tell you guys what you should always do as what I did with this unit I knew nothing about it so when I got the unit I always take a look at it just physically take a look take the top cover off take the bottom cover off just look with my eyes first but after that I power up the unit normally with a variac like I did with this unit and then once it's powered up I want to know what works and doesn't work before I start working on it because years ago I might take a unit it and just real quick Power It Up how it works and then I started working on it and then down the line I find out I did something to break it so I want to know what's working and what's not so what I did with this unit is I tried the FM and the AM tuner they seem to work both channels seem to work and then I went ahead and tried a CD player in the auxiliary port and that seemed to work again both channels seem to sound fine then I hooked a turntable up and I had a loud hum very similar to what you would have if you didn't have a ground hook to your turntable from your receiver you had just this hum and so I knew at that point something was up I didn't know what was up but I went ahead and started the restoration and figured I would go through the phono section I was going to go in there and recap it and everything so I figured I'll get to that when I get to it and this way that though I knew what was working and what wasn't so I didn't get done with the phono section and then say what's this hum did I have it to begin with you wouldn't know so I didn't know I had a problem right from the first time I tested this 2500 and needless to say I still had the same problem after I had worked on the phono amp and selector switchboard that I showed you earlier in the video so I had another problem and that was something I was going to have to troubleshoot to try to figure out what was going on with that what I'm going to do now is explain to you how I go about troubleshooting a piece of equipment and hopefully this is going to help you repair your piece of equipment now I see a lot of folks on YouTube that are very smart people much smarter than me going through and explaining how a circuit works and that's great but for most people they're just trying to keep their piece of equipment working or repairing their piece of equipment and I'm unfortunately in today's world it's hard to find anybody to work on the equipment and a lot of times you're the one that's going to have to fix it and it's unlikely that my problem with this phono section in this Brand's 2500 is going to be your problem with your piece of equipment so I like to show in my videos like I'm going to show in this one the practical way that most people need to approach a problem with their piece of vintage audio equipment because most of us including me were not experts this isn't what we did for a career we just don't have as I mentioned the expertise out there anymore everybody's getting old everybody's retiring the old technicians are dying and many times people are left on their own so I want to show you in Practical terms how you may be able to repair your piece of equipment you may not be able to but I think this does a lot lot more to keep the Vintage audio equipment going by me giving you generalities about how to repair a piece of equipment than me taking you through a section like my phono section point after point after point after point and then showing you what happened why it happened and what components I changed to fix the problem because the odds of this being your problem Are One in a Million but me showing you in general how to approach any problem that you may have with your vintage piece of audio equipment I think can be valuable as I said before the first thing take a look at the piece of equipment that you're working on with your eyes and see if you can see anything then test it out test it out in every way that you can possibly can test it out with a CD player test it out with a turntable see what's working and see what's not the next step is for you to go to Hi-Fi engine Dot com and open an account if you don't already have one and download for free the service manuals the owner's manuals for whatever piece of equipment that you're going to be working on what you also need is a digital multimeter and this will allow you to troubleshoot a lot of different issues there may be a point where you need an oscilloscope to troubleshoot a problem and that's even nicer to have with an oscilloscope and with a multimeter you can fix pretty near 100 percent of the issues with vintage audio equipment with just a digital multimeter you can probably fix more than half the issues that you're ever going to run into so let's get started into how you approach a problem in a piece of vintage audio equipment and we're going to use the problem I'm having with my Marantz 2500 as an example but as I indicated this could be any problem in any piece of vintage audio equipment and I would go about approaching it the same way so I have a hom in my phone action and I know it was there originally because I tested out everything and I had it before I did all this work on it all the restoration work changing out the old components I knew I had a hum so now I have to go back and figure out what that hum is being caused by so I was thinking oh no I don't want to get back into that phono amp and selector switchboard if you guys saw earlier in the video that was a difficult one to work on because of the cabling situation so I was thinking how am I going to do this so many times you can think about the easiest thing to do and the easiest thing for me to do was to check the voltage coming from the regulated power supply to the phono amp and I saw on the schematic that was in the service manual that I tell you guys you should download that this circuit uses plus 31 volts and minus 31 volts I was able to get to the regulated power supply side easily I showed you guys earlier how easy that particular assembly was to work on it's mounted right at the top pull out a few cables pull out a few screws you can pull it right out you can see here in the photo that j805 supplies the plus and minus 31 volts to the phono amp and selector switchboard and that was easy to get at it's right at the top of the chassis so I didn't really expect this necessarily to tell me anything other than I knew I had the voltage going to the board and that's something you should always check first is to make sure you've got the voltage correct so I measured and I had minus 31 volts actually I had about minus 32 volts that's fine as I've indicated before schematics not going to be perfect so then I went over to the plus 31 lead and it was about 40 volts so that was too far off and that told me right there there's something going on with the power supply it's the regulated power supply I didn't know that was going to fix the hum but I knew that was a problem that was too far off especially seeing minus 31 was about minus 32 which is what you'd expect but plus 31 if it was plus 32 that'd be fine but it was around 40 volts and I knew that wasn't fine so finding out that I have an issue with a voltage really Narrows down where this problem can be as I said it's got to be on that p800 power supply and I can't tell you how many people get a hold of me and they say well how do you figure this stuff out I look at it I take the cover off and I can't I don't even know where to start this is how you do it you can narrow it down many times to a particular board or a particular section and then suddenly finally it's not so daunting right you look and you think I don't know even where to start I know where to start now and this is the same way that you can troubleshoot your problem and then suddenly it didn't fix your problem but at least you know what board it's on and this eliminated 90 of the rest of the unit and that makes you feel good that now maybe you've got a chance to fix it because you've diagnosed the problem you know where the problem is and then you can get in there and try to fix it pieces of audio equipment like this Marantz 2500 they were made to last for years and they were made to be repaired but this was long before the internet and the manufacturers had to provide documentation to the service centers so this equipment could be repaired and what they did is to mark up their schematics I wouldn't have known I needed plus and minus 31 volts to my phono section I I would had no idea I wouldn't know if I needed 10 volts or 50 but it told me 31 volts and this allowed me to measure that and say this is not correct the rest of the schematic is marked up also you notice that they have q symbols for transistors they show c's for capacitors R for resistors Etc and they show you different voltages at different points so you don't have to know exactly how this works and they understood that that not everybody's going to be able to look at this schematic and know how this works and frankly most people aren't so I was able to trace back in the power supply where my issue was with my voltage problem and it was a bad transistor and that made sense to me because I changed all the electrolytic capacitors so I was pretty confident those were good resistors don't go bad very often so it may made me think about the transistors and what I used to test them with was an atlas DCA Pro that I have now by no means do you need one of these to find a bad transistor you don't that multimeter that I told you that you need a digital multimeter that would find this problem just as easily a reason I use this Atlas DCA Pro mostly is for gain matching transistors and I did do some gain matching of transistors in this particular unit you really should still gain match any replacement transistors that you replace in the audio path so I had my 31 volts now instead of around 40 I went ahead and hooked the turntable up gave it a shot and what do you know sounded great no hum whatsoever so I'm glad to put that behind me so I think I've got everything pretty well tweaked with the 2500 I think everything's working properly and then I go and I use the mode switch which do you know the mode switch it's the one I never use and I just told you guys before you get into a project make sure you know what's working and what's not working well the mode switch is that switch that has five different positions on it stereo which is way I always use it reverse I guess that's used if you hook your speakers up backwards and you're too lazy to reverse them back then you've got left and right which mixes the left and the right channels together then you've got the Left Channel only and the right channel only what are you going to use that for I've never used anything but stereo and this kind of proves it because I want to use that switch it doesn't work it doesn't work and I'm going no no no no no no no how can this not work frankly I wouldn't known if it would ever worked anyway because as I said I've never used a mode switch on any piece piece of equipment I have back when this receiver was produced a lot of the receivers had this and I don't even know why I really don't know why they had it but they had it and I've always left mine in Stereo and was able to figure out what the Left Channel was and what the right channel was and got my speakers hooked up right so I never touched it so now I'm I am thinking oh no because I've got to go back where I've got to go back to that phono amp and selector switchboard which is a pain in the butt to get to well I can whine all I want but now I've got to take it apart again and that's how it goes and just as I told you guys make sure you all know now what's working and what's not and what do I do this is a problem I'm sure that was there from the beginning but I didn't check it out close enough so now I pay the price and I'm gonna have to go back in there and fix it because I can't leave it like that it would bother me to know something's up with it and I just ignored it so I've got it apart again and in my hand is the mode selector switch that I removed from the phono amp and the switch selector board and my issue is there's a metal shaft that should go through this switch and I'm showing you this hole from the back side of the switch and I don't have that little metal piece what that little metal piece does is moves this switch assembly to different contact points so here in this picture kind of shows a little white wheel looking thing there in the Middle with kind of a rectangular opening and this shaft should be press fitted into there and there's no there's no shaft there's no piece of metal so when I turn the knob in the front nothing happens and what should happen is these different contact points are met and then you either have stereo reverse stereo left and right or left and right by itself I've got to find a solution for that because that's not like something I've got that I can just pull out of my toolbox as it turned out it was something I could pull out of my toolbox I thought about what can I use here and a one and a half a millimeter hex wrench just about fit in there right I had to press it pretty good but that was good I wanted it to be tight because I didn't have this particular part and I wasn't going to probably be able to find one so I went out to the garage and I cut an old hex wrench cut a piece off of it and I brought it back in and I fit it into the switch it's not exactly right I'd much rather have what I'm supposed to have in there I could turn the knob and the switch would operate so that's what I'm gonna go with here because I don't have any other choice I don't have a whole switch assembly and as I said I don't have the parts for the switch assembly either so but that's a good enough solution for me at least I know what happened now what happened I don't know why is it missing so maybe if the unit was handled rough or maybe over the years it just fell out somehow which I kind of doubt but I I don't know I I've never saw it when I originally looked over the unit I don't see it now I looked again and this little metal piece you think would rattle around a little bit and if I shook the chassis around if it was in there somewhere I'd find it so and I can't tell you if it was ever there and initially lost it or if it was never there but all I know is I don't have one now and this was a solution I used I made my own little shaft and I think that'll work out okay so now go ahead and re-solder the mode switch back into the phono amp and the switch selector board and make sure that working well getting closer to bench testing this 2500 but first I'm going to go ahead and test out all the various features and make sure that everything's working as you just saw sometimes things can come up at the end that you don't expect so I'm going to go through everything make sure it's operating properly and then I'll get to the bench testing the 2500 is unique because it has an oscilloscope built into it many of you guys who have either FM tuners or receiver that has a FM AM built into it you have a signal strength meter and some of you have two meters another meter for accurately tuning the center of the station but in this unit's case you've got an oscilloscope is that a little bit over the top maybe but it does have some advantages first of all you have a button on the display which is called tuning mean and what that does is basically show you the same thing that your signal strength and your Center tuning meter would show you in a conventional tuner so when you get off a little bit left or right of the station it shows you on the display with a trace that it's a little bit off so the idea is to get the maximum signal strength and to get the station centered the exact same way that you do it with your meters no difference whatsoever then you have a maldi path button on the front of this 2500 and that may be the most useful feature because that would accurately allow you to get your antenna alignment correct back in the day I could remember trying to draw on stations from 100 miles away 150 miles away this is helpful if you're out there trying to adjust your outdoor antenna are many of you guys doing that today probably not but back in the day it would have been quite useful and then you have another button on the front called scope audio and that button there what you'll see if you push it when you have a stereo program you're able to see the stereo separation and the modulation of the signal now does that have a purpose I don't know that it does it looks kind of cool in certain music it looks very cool you can get some very interesting displays on your scope but for the most part that is just eye candy and it doesn't do anything really for you I went over the oscilloscope a little bit more in detail in this 2500 because that was a pretty unusual feature in a piece of vintage audio gear or in a piece of gear today probably even more so the rest of the 2500 was pretty conventional by 1970s standards especially in a high-end receiver like this you had AM FM two phono inputs on auxiliary it would support two tape decks it had a good range of tone controls it had a high and low filter loudness button FM muting supported two speaker systems 2500 does have one unique or maybe not unique it's not the only receiver amplifier who has this but it has Peak indicators and in moranza's case they build a circuit that was designed to follow the variations in the power supply and by load impedance and supposedly That was supposed to give you a more accurate indication of when this receiver is actually clipping I've never seen these indicators light up and I don't think most people will not when you've got 250 Watts a channel into 8 ohms and 330 into 4 Ohms here I'm showing you the the rear panel of the 2500 and up the top left you can see where it supports two speaker systems just to the right is the am antenna down below the speaker systems is that new fan I'd put in to the power transistor tunnel next to that is the AC Outlets there's two of those right under the am antenna toward the top there's a muting level adjustment and that's for your fm then next to the muting level there are two controls one labeled Focus one labeled bright now that's not what you'd normally see on the back of any piece of vintage audio equipment and what those have to do with are that oscilloscope and so this is where you adjust the focus and the brightness of the oscilloscope and it's pretty straightforward there's actually a procedure in the service manual for it but if you turn those adjustments even without following the service manual and you look at the oscilloscope in the front when you turn the focus you certainly can see it come in focus and go out of focus and same with the brightness control you can see it getting dimmer or brighter so you can adjust those however you'd like below that is the external am and FM antenna connections that's this conventional like any receiver would have below that you have your RCA input for your phono and your auxiliary and your tape monitors it also has a main in and pre-out RCA jacks now this is a little bit different than the earlier marancas you guys have earlier marancas have a jumper that goes between your main end and your pre-out if you don't have that Jumper in you don't have any sound but in this unit it only breaks the connection if you plug in RCA cable in so you don't need those Jumpers in this 2500 at the top right you see a Dolby FM decoder receptacle there's just kind of a hole and you could purchase a board from Marantz and then you would be able to listen to Dolby FM broadcasts Adobe FM just didn't take off like it did in tape decks tape decks it became a standard but with FM it just never caught on even though it sounds like a good idea to help reduce the noise in an FM broadcast but it just didn't happen one more thing to add about Dolby FM if you look at the selector knob on the 2500 there's two possible FM selections there's FM and then FM 25 microseconds 25 microseconds that's the one you would use with Dolby FM broadcasts and in today's world there is no Dolby FM so you would always just select the FM position and in addition you would need the decoder in this 2500 for it to operate I've gone over most of the features of the 2500 and highlighting the unique features of this particular receiver like the oscilloscope but these items are things that you can see it on the outside now I'd like to highlight a couple features of this receiver that are on the inside that you don't even know that exists there are two thermostats in the 2500 attached to the power transistor tunnel that I showed earlier that I rebuilt and I put a new fan in and this fan draws air through the heat sink tunnel it is controlled by a thermostat normally it will just run on low and it's very quiet you get away from the unit just a few feet you can't even hear it if you're playing music you're not going to hear it at all and matter of fact I've never heard it kick onto High playing music so it's a two-speed fan it's either going to run low or it's going to run at a higher speed and the only time I've ever heard it go to the higher speed is on the test bench and I'm going to show you that in a little bit so the heatsink tunnel has to go beyond getting warm it has to get very hot before the fan kicks into the high mode the second thermostat is activated at even a higher temperature and what that does is disconnect your speakers from the output transistors and what the higher temperature is I really don't know but it's something higher than what the fan on high speed can handle and I've got to tell you this part from the service manual before I get to the bench testing is it's got to be extreme because in the service manual and I when I read this I thought this was Insanity they talk about running a continuous sine wave which is what you do on the test bench at 330 Watts a channel into four ohms and you think all right well that's what it's rated at that's what it should do the testing periods 45 minutes 45 minutes I mean when I read that I thought that was Insanity I mean I don't care if this is 1977 but this just shows you the quality the engineering that went into this there is no program material you can play that even comes close to a sine wave running at maximum power through this receiver this isn't even going to shut the amplifier off I I don't know what is going to but this is part of the testing that you can do with this particular receiver I just when I read that I I just my job out dropped because there's no way I'm doing 45 minutes at 330 Watts a channel into four ohms I also own a Pioneer SX 1980 which is a monster receiver in its own right and it was produced in the same time frame that this Brand's 2500 was and I just want to bring up some of the advantages and disadvantages of each of these receivers earlier in the video when I was rebuilding building the regulated power supply in the Marantz 2500 I talked about my Pioneer SX 1980 and how the regulated power supply was mounted at the bottom of the chassis and here I show you where this is mounted and you can see how in this 1980 that power supply could get very warm and as the years have gone on many SX 1980s have had power supply issues and most people think it's from just cooking itself to death literally being at the bottom of the chassis there's just no way for that heat to be able to get out of the SX 1980 so marantz's positioning of the regulated power supply of the 2500 allowed it to be able to get the heat out of the chassis much easier being mounted at the top and speaking of the power supply as I mentioned earlier in the 2500s restoration there's been a number of reports of having power transformer failures in both the 2500 and 2600 as far as the Pioneer SX 1980 goes there's been none of that I'm not saying one has never failed but there were many more SX 1980s manufactured than there were 2500s and there's really no reports of the power Transformers going bad in them so there seems to be a little bit more of an issue in the 2500 as far as the power transformer compared to the SX 1980 both of these receivers are first class top-notch both in the engineering and the manufacturing but I wanted to bring up just a couple issues with both these units that have popped up over 50 years gee what a surprise and probably going to be more issues when somebody's talking about their SX 1980 or the Marantz 2500 and another 50 years when they're 100 years old and I wouldn't be super surprised if both of these units aren't still operating at that time I want to compare some of the features of each receiver and I'm going to start with the toners and you saw earlier with the 2500s oscilloscope how that can be a benefit to getting the best signal and the best quality signal when you're listening to radio now the Pioneer takes on a different approach a very sophisticated approach it takes on an approach where in my SX 1980s K some of them didn't have this this is a later one this was built in 1980 it has a quartz lock feature and when you touch the tuning knob which by the way weighs about three pounds right this machined aluminum knob you'll see three leads and these indicator leads which are fine-tuned quartz lock and stereo and when you touch the tuning knob these turn on and off when you get near a station and so you get near to where you're tuning it in and when you get close the fine tune will come on and if it's a stereo signal the stereo lead will come on and then you can release it and then you'll get the quartz lock and that makes sure it's dead on different than the 2500 right the 2500 is kind of like for a tanker like me I'd be out there trying to turn my antenna trying to get the best signal to see what the scope said I think I would have liked a 2500 back in the day I couldn't afford one then but I would have liked one just to mess around with where the SX 1980 is pretty foolproof look get it close we'll light some leads up for you let it go and go sit down and just know that you are getting the best reception that you can possibly get look I get that nobody listens to FM it doesn't matter to me I enjoy the stuff I enjoy reading about it I enjoy making sure it works correctly do I listen to FM hardly at all I'll turn on like a piece of equipment like this and just let it warm up with some FM or something but there are no good FM stations in my area anymore and I think that probably holds true for most of the country but I just love going back making sure everything works properly and I guess kind of reminiscing and thinking about what it would have been like to own this piece of equipment back when I was a teenager or a young adult I'm not going to go through every input difference between the two receivers but the tuner sections were quite a bit different so I wanted to do that and one other area is the phono section they both support two turntables you've got a phono one and a phono 2 on both the 2500 and the 1980. the difference is the Pioneer you have two front panel selectors to be able to select the load for whatever cartridge you're using the Marantz 2500 has a fixed load in the 2500 the phono input impedance is a fixed 47 000 ohms along with 100 picofarads of capacitance when you hook a turntable up to your 2500 that is going to be the load that that cartridge is going to see and in most cartridges cases that's fine but the sx1980 gives you three different resistance levels 10 000 ohm 50 000 ohm and a hundred thousand ohm along with four different capacitances a hundred picofarad 200 picofarad 300 picofarad and 400 picofarad is that going to make a difference it could in some cartridges but most cartridges are going to be perfectly happy with something around 50 000 ohms and a hundred picofarads I have a couple sure v15 cartridges that sound great with a Marantz 2500 so in my case not having that flexibility to be able to change the impedance or the capacitance really doesn't bother me any now I do have a couple moving coil cartridges also neither one of these receivers support moving coil both of these receivers are Monster receivers the 2500s rated at 250 watts per Channel and the SX 1980s rated at 270 watts per Channel and they go about producing their power in a similar manner in in some aspects using the technology of the day in the late 1970s they use the same general designs but they both had the same issue and that was dissipating heat and as you saw earlier Marantz took the approach of having a small heat sink area and then having to combine that with a fan to be able to keep the output transistors cool Pioneer used the tried and true method a big old heatsink one for each Channel mounted on opposite sides of the chassis and that's one of the reasons why the SX 1980 weighs around 90 pounds which is about 30 pounds more than the Marantz it's a beast I rebuilt my Pioneer SX 1980 a few years ago and I want to go through a little bit of what this receiver was like to rebuild comparing it to the Moran's 2500 as I mentioned earlier in the video the 2500 was a challenge for me to restore there's not much difference between the 1980 and the 2500 as far as starting out to open up the chassis getting the knobs off getting the face plates off you go about that in pretty much the exact same manner for both of them my main gripe with the 2500 right was at the bottom of the chassis where it was difficult to work on the assemblies down there because they didn't give you very much slack in the cables and many of the cables were wire wrapped onto the board so you would have had to remove 20 or 25 wires to get these assemblies out of the chassis now I was able to work on them and it wasn't impossible to do it was just more difficult than what I felt it had to be now the SX 1980 has even more point-to-point wiring so you would kind of think well this is going to be even worse but it wasn't it was quite a bit easier to get these assemblies out and the number one reason was because they gave you plenty of slack in the cabling so once you got the tie wraps undone you were able to move these assemblies where you needed them you could get them outside the chassis now they were still hanging by a bunch of wires that were wire wrapped but that was okay because you could maneuver it where you needed to you just had to be careful not to bend the wires back and forth too many times or you're going to break them like any wire but the Marantz there was not enough slack in those cables and so everything was difficult because some of them had connectors years but then you remove the connectors and the point-to-point wiring they had was just too short wasn't too short to assemble it they got it together obviously at the factory fine but it was going to make it much more difficult to work on it like I had to work on it when I was going to restore it 50 years after it was built not everything was difficult in the 2500 as you saw before many of the modules came right out and I was able to work on them easily the 1980 the same way there's several modules that just come right on out of the unit but just like the 2500 it's kind of a combination some of the boards have several wire wraps some of the boards just pull out with connectors and as I was mentioning both of these receivers were designed at the same point in time so the engineering of both of these receivers how they were manufactured and the parts used are very similar between both the 2500 and the 1980. I just wanted to talk a little little bit about both receivers and the differences between them but as I said there's a lot more similarities between them than there are differences either one of these receivers you get it restored and they'll operate well for decades to come I used a service manual to find the idle current adjustment procedure as well as the DC offset procedure and I did that before installing the 2500 back into its wood case now I'm getting ready to bench test the 2500 what I'll do first is hook it up on the test bench just with a pair of small speakers that I have here on the test bench make sure that everything seems to be working fine let it warm up a bit and I'll just let it sit there for a few hours and just sort of cook along and make sure everything's okay before I start bench testing I have my signal generator my multimeter my audio analyzer along with the uh Marantz 2500 and my load resistors and I'm going to just go ahead here and start doing a little bit of testing and at the moment I've got a 1000 Hertz sine wave running into the auxiliary port of the 2500 and I've got running here now about two and a half volts per Channel and it's just sitting here uh idling along more or less so at this point what we can do just to see what our Distortion is on each Channel I can go ahead and look at that and it's about 0.02 percent on the Left Channel and on the right Channel it's about the same so that's uh very good this unit is rated at 250 Watts a Channel at 0.05 percent Distortion into 8 ohms so that's well within its range so we'll go back here and take a look at both channels again and as I said we're running about two and a half watts per Channel and I'm gonna go ahead well you know what I'm gonna do first just real quick while I got the probes it's sitting down there hanging in front of my analyzer I'm going to just turn this down for a second and I can get in here um these leads here are going to the load resistors that are sitting up here on the 2500 and there's a little Gap in here you probably can't see that I can get my scope I mean get my multimeter probes down in there and I'm just going to see what the DC offset is yeah I haven't looked at that so let's see what we got and this is the Left Channel and we've got about six millivolts a little under 5.89 that's that's fine let's see get in here try not to short anything out right and we've got just the hair over six yeah 6.0 5 6.1 millivolts and we'll go back here and just look at you again for the fun of it yeah just about the same so we got five or six millivolts of DC offset which is excellent that's just where we should be and about as good as you can get so and you know for you guys that don't know DC at the speaker outputs ideally you want that to be zero volts no DC voltage at the outputs so when you've got just five six millivolts that is we'll call it zero so I'm going to turn this back up again a little bit I'm turning the volume control here on the 2500 and we're back a little higher than we were before like 3.7 volts 3.5 I'm just going to turn it up here a little bit because we're sitting at two and a half before okay that's a good spot uh we're sitting about 12 and a half 13. and let's just take a look again at the the distortion and I'm looking at the Left Channel again and just about exactly the same is when we looked at it when it was uh when we were sitting at two volts instead of uh I mean two Watts instead of 12 watts and it's about 2.08 so I'm going to go over here to the B side real quick which I say B because the sound analyzer is a channel a and a channel B which correlates on a piece of stereo equipment to the left and the right channel so when I went to channel B I actually changed over to look at the distortion on the right Channel and once again it's just about identical to what it was when it was down at uh two Watts so we'll go ahead and go back flat here again and we're right there at 12 and a half 13. so we're going to turn it up here a little bit as I said I'm not going to push this hard there's no reason to I mean am I ever gonna even run like right now I'm in the middle 30s uh middle about 34 watts per Channel and am I ever going to run this continually 34 watts per Channel there's not a chance there's not a chance because I'd be peaking at its Beyond most likely in most music I'd be peeking Beyond its uh capabilities but that's uh very good by the way this has a built-in fan and right now it's running on low you probably can't even hear it you really can even this as close as I am I can barely hear it now if it goes into high speed oh man you'll hear it it Roars and the reason this unit needs a fan is the heat sink assembly is pretty small it's kind of like a tunnel and really for the power of this particular unit they had to use a fan you just wouldn't be able to keep it cool so right now there's a fan run it's just moving a little bit of air through there so as I'm talking here though we're just sitting at 34 volts uh 34 Watts or so and I say volts sometimes because sometimes I look at the volts instead of the Watts and as you guys know ohm law uh well you can either look at this at Watts which most people think of their stereo equipment is capable of so many watts per Channel but it's also capable of so many volts per Channel but stick with Watts here so I'll go ahead and look at the distortion here we are just about the same again just about identical and I'll go over here that's the Left Channel now I'll go over to the right Channel and again just about identical of what it was when we were down at just a couple Watts a channel so that's outstanding we'll go back flat again and just touching the unit it really doesn't feel warm at all I'm back here touching it the load resistors have a little heat to them and I'm putting my hand back here yeah it's blowing a little warm air you know the Fan's blowing some warm air out of those uh out of the heat sinks that little that little tunnel where the power transistors live so gonna go ahead and keep running it up here a little bit Not Gonna Go Far you know I'm just not going to do it it's not worth blowing it up as I said again I'm really just worried about the Transformer more than anything else but here here we're at about 50 Watts a channel and I'll go ahead and look at the Distortion there and once again it's it's not practically not changing right we're 50 Watts continuous and again this is continuous this is the music Peaks this is pegged right there at 50 Watts a channel and that's the Left Channel now we'll go to the right Channel and again 0.02 it hasn't changed and I would be willing to bet you that if we kept going it wouldn't change all the way up but this is being pushed harder than this receiver will ever be pushed once again as I said earlier if you're doing 50 Watts is your low point with your music you better have an amplifier that's as big as this one now did you hear that I don't know if you could hear that but the fan kicked on and it's much louder I mean it's it's you probably can hear it I hope you can hear it because normally you don't hardly hear it at all when it's on low but now we've got it running hard enough and sure enough if you go back here I can't get down here on the heat sinks but I can feel the air blowing out of that tunnel yeah it's warm it's warm so normally I've never ever had that fan come on when I'm listening to it and I and I'll listen to it loud because normally what's happening right you're listening to music and you got those Peaks but it's not pegged there 50 50 watts per channel of course if you ever had music playing to the point where this fan kicked on high you're not going to hear the fan anyway right you're not going to hear much of anything except your ears ringing as well as this Moran's 2500 did on the test bench it's not perfect cosmetically as you've seen in this video and if you guys have seen my videos I could care less if they're in perfect condition I know I'm a little bit odd that way because I'll see everybody talking about how their receivers in pristine condition or they're looking for one that's meant I could care less what it looks like because this unit tells a story it operates like a new unit does or as close to possible or as close as it can to a new unit it just doesn't bother me that it's not perfect in this particular unit sits on a shelf doesn't sit in a glass case sits out out gets dusty you know most of the time I don't let it get too terribly dusty but it does it gets a little bit Dusty and the case even though it's an original case it's all banged up it's all scraped up and that's all okay with me because it operates well and it just tells a story for me it tells a story of what it went through probably I don't know the whole story I do know the guy found it at an estate sale out in Texas the guy bought it for him he didn't know nothing about it as you saw earlier in the video this 2500 had several different issues and almost for sure they didn't all happen at once they just kept piling on something failed 25 years ago then something failed 20 years ago then 15 years ago then finally it got to the point where somebody just stuck it in the closet and said I'm done with it and it sat there until I got it I estimate I had probably 40 hours into this project between repairing the 2500 and restoring it and testing it and going through everything so it took some time but as you guys know I'm a hobbyist I don't do this as a profession so no big deal to me the time and the money involved was minimal most of these parts are pretty inexpensive I didn't have to replace anything that was expensive at all and I've probably got not much more than a hundred dollars in Parts but one thing I want to bring up is for you guys who expect somebody to work on this equipment for you anybody who's going to be competent it's going to be a big job for them even though I'm not a professional and maybe a professional could do it quicker it's still going to take a lot of time and any of you guys who call electricians or plumbers or anybody to your house to do anything know how expensive things are so if you purchase one of these units and you expect someone else to work on it expect it to be a very expensive repair slash restoration whatever you need if somebody's going to have to spend a lot of time on this unit and it's going to cost you at least several hundred dollars for the labor if not over a thousand dollars for the labor then you got to throw in the parts and the whole nine yards so this is why I put together my videos in the format that I do my videos try to show you how you may be able to repair your own equipment whether you obtain one at a flea market whether it's one that you've had for years that has now got issues whatever the reason because the major cost of repairing or restoring vintage audio is the labor the parts generally are not that expensive there's some exceptions to that but generally it's all about the labor so if you've got the time and you've got the patience to learn something new and you've got some minimal equipment you may be able to do this yourself and in today's world where it's getting more and more difficult to find a competent technician you may may have no choice but to work on your own equipment have a Moran's 2500 sitting in a room people are going to gravitate toward it whether you're older like me and you've got a general idea hey that's an old piece of stereo equipment or you're a younger person wondering what is that thing now what's it sound like it goes without saying it's effortless as far as power is concerned let me just say it's enjoyable and that's the main goal in this hobby is to enjoy it and this 2500 is a joy to power up and to listen music through and to look at what more can you ask for in a piece of vintage audio equipment I hope you enjoyed the video I know it was a long one there was a lot in here and any of you guys that are still hanging after your sixth beer or sixth cup of coffee I really do appreciate you watching it and if you enjoyed it please give me a thumbs up down below and for you non-subscribers if you enjoyed this video and you'd like to see more of them please subscribe and as always thank you so much to my present subscribers y'all have a good day

Channel: Vintage Audio Addict

Views: 250,546

Keywords: marantz receiver, vintage marantz, vintage audio addict, marantz 2500, most powerful, marantz

Id: mfRzHomUb2Q

Length: 134min 29sec (8069 seconds)

Published: Wed Feb 08 2023