Receiver Complete Alignment With Extra Tips!

hi everyone and welcome to another episode of mr. Carlson's lab today we're gonna perform an alignment on this Westinghouse 275 radio receiver that's the radio receiver right there this is the complete alignment so grab your favorite snack and a beverage let's get started since the last video when we did some troubleshooting in the chassis here I've done a lot of work on this and the reason that I have done a lot of work on this is just because the other work was really messy with that j-hook method I didn't know if the capacitors were installed the correct way so the outside foil end has to go to the lower impedance portion of the circuit so all the new capacitors have been marked and installed correctly I really don't know the quality of those other capacitors so I just got rid of all of those and I installed all of these really high-quality Illinois capacitors so this is part of a verified parts list that I have on patron so I've spent a lot of time grading and testing lots of different components and I have multiple lists up there with verified components for rebuilding stuff like this so these are part of that list I replaced the electrolytic capacitors here with some high-quality Rubicon capacitors got rid of the dangling capacitors and here in the ones that were taped down here and then just put these in properly the original big wad of black tape that was taping you're holding all of this together basically and there's a big solder blob on the underside of it I got rid of that and on the old filter capacitor what I did is I threaded the stem that sticks out of it so it's an aluminum stem I threaded it to 6:32 and then put a standoff on the top of this stem so it's insulated from the old capacitor the capacitor is just holding this here so this is a tie point so that really cleans it up I've replaced the line cord with a reproduction line cord and it's a polarized line cord now so the hot side of the line cord is to the fuse the very first thing and then to the rest of the radio receiver which is a very important safety thing to do replace quite a few resistors in here just in odd places because they were a little out of Tolerance and some of them were noisy replaced even some of the mica capacitors some of the mica capacitors were leaky as well that's really odd for those mica capacitors usually they're really good so just lots and lots of work going around in here took the controls apart clean the controls out multi-step process that I have and I'll share that process that really is an entire video these say right on the back of them do not take apart why they say that I have no idea because you take the back off it and it's a normal potentiometer inside there's nothing inside it that's out of the normal so anyways I took them apart and cleaned them right out so the tone control and the volume control up here got cleaned out there was a wrong value on the volume control so when the volume control was right down to the bottom it got very base E and muddy and then as you turn this up it got clear and then of course that base E and muddiness went away and that was because there is a wrong value of a resistor in a sleeve so it was 39k ohms it was supposed to be and they put a 39 ohm resistor in there so that really added to the base and the mud kind of really low frequency sound so since there's a tap mid way up on the actual volume potentiometer it it changes as you turn it up so it starts out bass ear at lower volumes and then of course as you increase the volume that bass drops down a little bit and then of course you know that way it doesn't make this speaker get all muddy at higher volumes or you know I guess distorted I should be saying at this point so that was done just lots and lots of things done to this thing to to bring it up to normal again basically it was actually really surprising how well it worked before so now I expect this to work really really well so now what we have to do is do the alignment and the first thing we have to do is on line the if' transformer and our two of them the I have transformers and then we'll go through this section here which is the oscillator and RF an antenna section and we'll get in here and tune this entire section up so there's a lot of adjustments here what I'm going to do is adjust this out of the case I'm not gonna put the bottom on it to adjust it first because then you won't see it being adjusted if I have the case on it right and then once I finished the adjustment once I've done the alignment with the case off I'll put the bottom panel back on as mentioned before and then I'll retouch up the alignment as mentioned there are alignment holes in the bottom metal panel there's a bottom metal shield for this and you're supposed to go through that with your screwdriver reason being is because this will capacitively couple to the bottom panel and when it does capacitively coupled to the bottom panel it'll drag the alignment off when you put the pan back on so that's the reason I'll have to go through this and touch up the alignment again a lot of this was explained in the previous video I'll put the previous videos link just below the show more tab under the video's description so if you haven't seen the original troubleshooting video definitely check that out as well I'm ready to perform the if' alignment on this radio receiver and in order to do that I need to adjust this capacitor here this one here this one here and this one right here those are the four capacitors that need to be adjusted for the if' and that's pretty much it there are no adjustments on the top side of the chassis whatsoever everything in this radio receiver is adjusted from the bottom side so these are the if' transformers and the capacitors are right inside the if' transformer itself now the if' or intermediate frequency for this radio receiver is 460 kilohertz it's not 455 like most AM regular receivers the reason that it is 460 is way back in the day a certain company if you do the research you can find out held the rights to 455 kilohertz and if any other radio company used that if' frequency they would have to pay rights so what they would do is they would use for 56 or 460 or 465 kilohertz for their intermediate frequency and that was absolutely fine now if I was to Justice radio receiver to 455 when it's supposed to be for 60 it'll cause the dial alignment to be off just a little bit not by a whole lot but off enough so whenever you have a radio receiver like this you want to use the specified intermediate frequency in or to do the alignment that is really important now in order for me to inject a signal into this what I want to do schematic here and show you on the schematic I want to feed the signal right in to the grid of the six eight eight right here this is an untuned area at four hundred and sixty kilohertz so I want to tap right into here with an isolation capacitor and feed a signal into here and that'll use this tube somewhat like a buffer which is to my benefit and I can feed just a little bit of signal through here and align these two if' transformers I'm picking the signal off at the grid of the 6f6 so that's the jumper clip right here and that runs down to my vacuum tube voltmeter which we'll take a look at here in just a moment and all I'm doing is I'm picking the signal right off of the control grid that allows me to align this without having to tie my vacuum tube voltmeter into the voice coil where there's a lot lower voltage especially right across a voice coil so basically it causes meter deflection a lot easier if we tie in at the control grid of the 6v spear 6f6 right over here okay so I'll just show you what I'll do this line right here is the line that I need to tap into to feed the signal in so what I'm going to do is attach an isolation capacitor to this that green wire runs off to the cap of that tube okay so I'll just click this on here like so alright and then what I'm going to do is attach the common of my signal generator output to the chassis and the signal lead to this isolation capacitor now the reason that I have an isolation capacitor on this right here is just because I don't want to drag the circuit at all with them the load of the signal generator itself or the RF controls it's always a good idea to have that in line so basically you can call that a blocking capacitor tool if you like all right depending on its purpose and where it's being put now if I move this over here you'll see the signal generator in behind right there and then what you'll do is you'll see my vacuum tube voltmeter right here and that's the frequency the signal generators at so the amplitude as you can see is way down back here so this one's right down at zero that's at about 4 and I'm on the low output so basically what I'm doing is I just want to turn the signal generator up just enough till I get a little bit of a tone coming out of the speaker and a bit of needle deflection here and then what I can do is twist those screws that we just look looked at on the bottom of the if' transformer until I get a peak so I'll move the signal generator around so you can see this move this is just the counter for my generator this this counter here and the signal generator is another video on youtube so it's the e 200 C video if you want to see the build of the the actual or the rebuild of the signal generator and this is another video as well building this frequency counter into an old clock housing so what I'll do is I'll just move the signal generator around and you can see that numbers move right there so that's at 460 killer it's right now so what I'm going to do is I'll go over here for a second I'll just show you this again so what I'm gonna do is turn up the volume until I get just a bit of a tone here that it's a lot of volume it's at full volume right there I want to put just enough signal into this radio receiver just enough signal so that it can hear a tone and then what I do is I start peaking knees up right here okay so I'll start at the bottom one and just move my way up so the bottom one is number one we'll call that number to that number three and that number four so remember that and I'll tell you what when I'm adjusting when I'm moving the screwdriver around and we'll keep an eye on the meter over here okay okay so what I'm gonna do is start adjusting number one rate now so I'm looking for a peak remember right there is the peak for number one so now I'm going to move up to number two [Music] okay so now I'm going to turn the volume control down [Music] and I'll keep adjusting this so if you pass it you just go the other way with a screwdriver [Music] right about there is the peak so now I'm going to go to number three [Music] Wow this is way out of adjustment Wow Oh that almost took three turns so now what I'm going to do is turn a signal generator down now I'm gonna go and adjust number four don't want too much signal there Wow you can really hear the receiver coming to life so with number four it's very very touchy and just using this screwdriver here this is fine for most adjustments in here but what I'm gonna have to do now is get an insulated screwdriver and go through and readjust these again I also wanted to use this screwdriver at first because I don't know how stuck a lot of those capacitors are so this allows me to break them free and then what I'll do is I'll go through the adjustment again with an insulated screwdriver so I'm just gonna go grab that screwdriver right now and I'll be right back okay I have a complete plastic screwdriver here and I'm just gonna touch up this last one again and we'll see how close we are and I was right there in any rate so what I'll do is I'll just redo that again so I'm going to start off at number one so I'll just move the camera here and show you what I'm doing so I'm going to start off at number one again I'll go to number two number three this is the one that took about three turns this one right here and then I'll go to number four with an insulated screwdriver now that I know that all of these are free and again I'll end up doing that with all of these here as well because over the years these things get sticky and if you use a plastic tool like this you'll just break it in there so you want to make sure that they are free before you start moving anything so we'll go through it one more time and we'll see so here we go number one it's pretty much right there number two here's number two and as loud as it gets now keep in mind that we're just looking for a peak and this signal is very very low right now it's very very low amplitude signal here go back to number three here and that's about as high as it gets and of course if I just breathe on the volume control now Wow lots of sensitivity there so what I'll do is I will disconnect this like so and you can even hear the static and the speaker now no one tena so that increased the sensitivity a lot so the next thing that we need to do now is perform the alignment in this section right here and this is a little bit more in-depth because it uh it requires us to take note of what's on the dial face so we have to put the pointer on the dial face to the specific frequency and then come back under here and align this so that the oscillator tracks with the dial and that's where a lot of people seem to get confused in alignment and I'll try and explain this just as clear as I can pardon the dust and dirt on the dial here I'm gonna get my fingerprints all over it on top of all this so I'll clean that all up later on so the first thing that we want to do is adjust the broadcast band and has to be done in order in this radio receiver so the very first band we need to adjust is this blue band right here the first thing we need to do is make sure that when this comes to the stop everything points to the line because if this is off if the needle is off which I can you know just by doing this I can bring it off right so it won't stop at the line anymore so we need to make sure that the needle stops right at the line so we need to adjust that first with the capacitor fully opened okay so it's not fully meshed there we go and you just touch that up right about there and that's close enough now it calls for 1500 kilohertz is the first alignment point so what I need to do is turn this to 1500 kilohertz okay so that's 1500 right about there I'll go past it just a little bit and that allows me to fine tune over top of it you can see that there that's 1500 kilohertz right there that's the first alignment point and then the second alignment point is down around 600 kilohertz so I have to turn the dial down to 600 so instead of me moving the radio again and showing me twisting the dial here down to 600 just remember that and I'll tell you when I'm doing that so this is the first point so what I'm going to do now is reposition the radio so I got to turn the radio around again and I'll get us all ready to the first alignment at 1500 so now we're ready to adjust the oscillator what they call the detector and the antenna section is multiple different names for the detector area but we'll use their terminology so this is the area right here that we need to adjust now you'll notice that we have these three adjustments here and then that one up in there so if we hold it like this it's not the right way so that is the right way because this is on this side here right so this is looking at the other side of the chassis so everything that we see is somewhat reversed on this so what we're going to do is we're going to adjust the 1500 first so if it's on this side obviously it's the far side because it's reversed so that's what we want to adjust first we have 1500 1500 and 1500 so this is the oscillator over here right again reversed it says oscillator so that is over here so oscillator detector antenna so what I'm going to do is turn out my signal generator I already have it set to 1500 here so I'll show you I have it set to 1500 right there and I'm going to turn up the volume here and what I'm going to do is rock the signal generator to see where this actually is so I'll turn this up so here lots of static but there's nothing at 1500 right so let's see where the dial actually is so I'll move the signal generator [Applause] [Music] so it's sitting at about 15 6263 something like that [Music] so what I want to do now to adjust the dial tracking is I need to adjust the oscillator and that's that adjustment rate down in there so now these are definitely going to need an insulated screwdriver to do this because he's going to be very touchy adjustments I have a couple of them here so hopefully these aren't too incredibly stiff I move them already I've just pre moved these with the metal screwdriver to make sure that they're free so I'll give this a shot here and hopefully I won't break the tip of my plastic screwdriver so we'll see if we can hear this first just brace this here and see that I don't know if you can see me turning this you know see that's very very tight so what I'm gonna do is I'm gonna use it's my little screwdriver to tune this just get it close and then I'll fine tune it with the other one okay here we go see how incredibly tight these are doesn't wants to jump out of that one [Applause] well that's way off [Applause] and give this just a little bit more signal and I found that again might have to turn the volume down [Applause] [Music] [Applause] yes [Music] [Applause] [Music] that's not too bad it's actually staying pretty close to being fine-tuned it with this [Music] [Applause] there we go so now you can hear that tone in there right get more signal so now what I've done is I've aligned the dial on the face of the radio with the oscillator inside you gotta remember this is analog and in order to create tracking between the two so as the dial is moving it needs to accurately track where the oscillator is you can see how much time the engineers would have put into this so chances are they started out with a blank piece of glass and they would just write in or you know even replace the glass with a piece of paper and just rode in where all the frequencies were and then spent a lot of time in this section designing a section that will track with what they've written on them on the dial face and then of course you're dealing with drift after that as well you know temperature causes drift in these older radio receivers and that's the reason that they use these mica capacitors because they're very very stable if you were to find the same value of capacitor as this so say we were to put up a Paulie style capacitor in place of this mica they are both the same value except this was now Paulie this thing would drift all over the place we just move everywhere with temperature so whenever you're designing an oscillator you need to use np0 style capacitors or mica capacitors just because you know just the slightest amount of temperature variation will cause movement right heat causes expansion right and then as it gets cold it contracts again and that expansion and contraction is basically moving the plates of a capacitor closer you know and further apart again so that's at the 1500 side of things so here at 1500 so now what I need to do is move the dial down to 600 I believe it is I'll take a look here at the alignment yep the next step is 600 Kasey's so I need to move the dial to 600 I'll do that right now and the dial is now pointing at 600 now I need to adjust my signal generator to 600 it's all movie camera here and you can see that just reaching behind here what's very close there's 600 right there okay give it some volume put the paper back down go over here now I need to adjust that up inside there so hopefully this outer portion is grounded and I can just use this and find that out yes it is [Music] [Applause] [Music] [Applause] there it is 600 [Music] so you can hear that [Music] now what we want to do that we've adjusted the bottom end we need to go back up to the top end again and make sure that the dial is still tracking correctly because you can actually stretch the band out by adjusting that and that so by adjusting this and this you can stretch the band or shrink the band depending on where those two adjustments are so now we need to go back up to the top and see if fifteen hundred or 1.5 megahertz is correct so I'll go back up here and if it's correct we would be doing good fifteen hundred let's move you back over here you can see this again put this back to 1,500 and as you can see it's moved the top end this is very common it's a little lower so what we want to do is adjust this again so I'll adjust this again again here trying to keep my hand out of the shot here but makes me angle the screwdriver which is uh makes it a little bit slippery in there just gotta brace the radio here as you can tell I'm just doing this by ear right now and that's absolutely fine I could be looking at the meter too and I'm just looking for the deepest tone I'll show you the meter as I'm doing this to give give it a bit more volume so you can see that [Music] all justice again [Music] and right there is about the deepest tone so now I want to move the dial back to 600 as you can see this is a time-consuming process mind you when a camera isn't involved it does go quite a bit faster [Music] and as you can see it's moved up just a little bit so I'll adjust that trimmer again and that of course is the one in the chassis here it's the one up top that I just adjusted okay and let's see what happens when I go back up to 1500 again hopefully it's getting a little bit closer move the dial to 1500 and we'll go back up to 1500 as you can hear it's a harmonic of that on the dial as well I would say that's dead-on turn that down so now the oscillator portion is adjusted and we're gonna have to touch that up again after we do all the rest of this because sometimes the detector section and the antenna section will drag the oscillator off so now we'll adjust these two here and then we'll check the oscillator again and it's like that with every band that's how these work so now grab the paper here so [Music] now we're adjusting for maximum sensitivity so I have to adjust the detector and the antenna section so let's go back over here to the meter and watch the meter these adjustments are made at 1500 so we're right at the right spot right now and so what we'll do is I'll quickly show you here so what I'm going to be doing next is I'll be adjusting this one right here and then I'll be adjusting this one right here okay the other ones are 417 megahertz right up at the top end of things [Music] okay so I'll adjust the detector now [Music] give us some volume can I turn this way down and still here it is that sensitive right now so it's obviously right up at the top [Music] [Applause] [Music] give it a bit more volume I'm gonna turn the tone down I'll show you how sensitive this is here in a moment [Music] the static is actually overriding the signal so I don't really want to give it too much because it's detecting this with the signal generator pretty much right down to zero okay so if I tighten the capacitor up you can see it drop right down okay alright so little does I'll show you that right now so it was pretty much peaked that one was already peaked it was doing very well and if I if I loosen the capacitor right you'll hear get louder you're that rape there's at maximum sensitivity for the detector stage now I'll show you how sensitive this is and when I'm talking about a bottom panel let's look give it a sec so I'm about an inch from the bottom [Music] so you can see why that bottom panel needs to be on [Music] if you want to see the meter as I'm doing that it's just me moving my hand close to it so there's the importance of the bottom panel acting a shilling for this one stage right here so the next thing I need to do is adjust the antenna trimmer in there an antenna capacitor so hopefully I can do this when it's getting louder now way louder focusing on the meter here so Nye started put it down here his boat down here that's about the peak there and as you can see I'm coupling as I touch the chassis with my hand and as I let go of the chassis with my hand right and that's with the bottom cover not on so as you can see the importance of having that bottom cover on to do the alignment it's very sensitive right now I'm pretty much at its maximum sensitivity for the broadcast band so if I just there's no antenna on this it's just the signal generator itself what I'll do is I'll disconnect the signal generator okay so basically there's the Box on the back here I'll show you there's the box on the back that allows me to couple my signal generator into the antenna jack right here this just runs through a BNC cable to the signal generator this is nothing on it it's a shielded piece of coax running out it's and how much static there is there that's really loud so this thing has got fantastic sensitivity when I hook an antenna to this thing I should be able to hear the bugs in my wall with this that's pretty crazy sensitivity there so the next is the shortwave bands the next band the adjustment is at 51 60 so 5.1 6-0 megahertz is where at so what I've done is I've tuned the dial this is on the green portion right here right to where they've pointed on this alignment here so almost in the center of the are just a little bit above the center is 51 60 now they haven't written frequencies on the face of this they just have AR a.m. and all that kind of stuff here which is I know kind of weird for an AM radio it is a really nice looking dial but it would have been nice if they at least had some sort of a reference to frequencies so now I have my signal generator set to 50 160 and I'm going to turn this tube and ban B which is the green dial on the face now I'll turn the volume up that's full volume and as you can see I'm at 50 160 but I don't hear anything so let's see where we are quite a ways off okay so there's 5160 now again you just do this by ear if you like this is the adjustment for 5160 right here so I'll adjust this first with the screwdriver and then we'll move to a plastic tool there it is just wanted to make sure that I'm not getting any type of a harmonic or anything like that and it's pretty stable just using that [Music] you can tell just pushing on it will cause it to move [Music] so there now what I need to do is tune for maximum sensitivity with these two right here very simple Wow [Music] so turn the volume down so show you that on the meter right about there we keep in mind this is me touching the chassis again now let go touching the chassis so you can see the effect of that bottom panel again so that's this one here now I'll adjust the antenna [Music] just gonna have lots of sensitivity you see how far out of alignment this thing is [Music] now some of you might be saying oh well it might be out of alignment that far because the bottom panel isn't on well that's a long ways to be out of alignment so I don't think so so this is definitely out of tune that's for sure so that's that one peaked up that's easy and then the last band is these ones right here and that's at 17 megahertz so I'll get that all set up and I'll be right back all right let's align band see so what I've done is I've moved a pointer on the radio dial right here so I've moved it up just a touch right to this little arrow right here and that's at 17 megahertz right there so before it was sitting right there the little arrow is pointing to so just a little bit past the center of the are now it's moved up just a little bit more sitting right there and I've also clicked the switch on the front of the radio receiver to put this onto band C so now since that has to be aligned at 17 megahertz we need to feed at 17 megahertz so what I'll do is all the signal generator there very touchy here it's me just breathing on the control almost need to fine-tune up here okay there we go very touchy signal generator appeared to get three zeros at any rate so there it is seventeen megahertz so now I want to go over here and I want to find seventeen megahertz so what I'm going to do is move the oscillator right here so I'm going to do that with this screwdriver here again because this might be a little bit stiff there it is steady the radio this is gonna be this is going to be very touchy high band always is [Music] [Applause] okay I've got it closed so now I want to get in here hopefully you can see this [Applause] there it is now I don't want to touch it so now I need to adjust this for maximum sensitivity and this for maximum sensitivity so come in here and adjust this one [Music] [Applause] [Music] right there so one will do is [Applause] [Music] [Applause] [Music] okay that's good and now I have to adjust the antenna section again this will need to be done with this screwdriver because these are so incredibly tight [Music] [Applause] so this one has got a bit of an odd tone so we'll take a look at the meter here just to make sure that we get this right [Music] the last one peaked up very easy could definitely hear the difference this one is not so much the same so we're going down so I need to go the other way and we're going down again [Music] and there it is that's at maximum sensitivity [Applause] with the bottom panel removed so now the dial is aligned everywhere and that completes the alignment of this radio receiver with the bottom pan off now the fun begins for me I get to put the bottom pan back on and do this all over again just to make sure everything is perfect once it's perfect I'll put this back into the case and we'll take a listen to it and see how sensitive it really is that should be a lot of fun so I'll get that all done and I'll be right back let's take a listen to the broadcast band on this receiver [Music] Gary Sinise [Music] million dollars god the interchangeable [Music] the stars and recompense that number as well an apology and correspondent Jennifer it calls upon us to come to a new stage also an eternity warning so as you can see lots of stations on the broadcast been working really good let's treasure what we've been let's take a listen to band B that's the green band right here this really isn't the right time of day to be listening there's not gonna be a whole lot there but probably for the time signal things [Applause] there it is [Music] [Applause] there's the time signal again [Applause] [Music] noise in here [Music] it's species rating there near history welcome to the club and that is the top end of the broadcast band so not too bad for really the wrong time of day to be listening to this so let's take a listen to the upper band let's take a listen to band see that's the red band right here now at this time of night there's not a whole lot of action on band see because it's really high frequency so different portions of the band come to life at different times of the day so up in here is gonna be pretty quiet so I'll just zip down through here might find the odd signal on these higher frequencies at this time so we'll just give it a try at any rate time signal there [Applause] [Applause] [Applause] [Applause] uncle one-five [Applause] [Applause] [Music] [Applause] so all in all not bad I honestly have to say that this is one of the stronger receivers that I've worked on for such a simple design and a really odd chassis layout this radio really performs well so around 8 p.m. something like that in that area at any rate this band here the red band is very very active on this receiver and there's lots and lots of shortwave signals in there again different bands come to life at different portions of the day or night so as you heard the AM broadcast band at this time of the evening is just buzzing so all in all projects successful this receiver works very very well and again it really is one of the stronger receivers that I've worked on it really does work quite well surprisingly well actually if you're enjoying these videos you can let me know by giving me a big thumbs up then hang around there'll be many more videos like this coming in the near future we'll be taking a look at vacuum tube and solid-state electronic devices alike so there'll be a lot of restorations coming as well so if you haven't subscribed now would be a good time to do that as well and if you want to be notified as soon as I post a new video don't forget to tap the bell symbol if you're interested in taking your electronics knowledge to the next level and learning electronics in a very different ineffective way and gaining access to many of my personal inventions and designs and there's also another 90 videos there as well you're definitely going to want to check out my ongoing electronics course on patreon I'll put the link just below the video's description under the show more tab and it'll also pin the link at the top of the comment section so click on the link it'll take you right there alright until next time take care bye for now you

Channel: Mr Carlson's Lab

Views: 119,565

Keywords: Radio repair, receiver repair, fix electronics, repair electronics, test equipment, vacuum tubes, electron valves, learn electronics fast, tube amplifier, tube radio, tube receiver, oscilloscope, DMM, VTVM, signal generator, frequency counter, fix equipment

Id: M-b8YEGqek8

Length: 53min 47sec (3227 seconds)

Published: Thu May 14 2020