PC archeology: The Leading Edge MP-2400L doesn't exist

well hello everyone and welcome back to Adrian's digital basement on today's video we have a PC archeology episode where we're taking a look at a Leading Edge MP 2400 L what's unusual about this machine is that even though Leading Edge was a pretty popular brand there doesn't seem to be any information at all about this particular computer it's a 286 it's really big it's full of cards and hard drives and interesting stuff and actually what's better than one Leading Edge MP 2400 L but two Leading Edge mp2400l well actually what's better than two two and a half I have a bit of a carcass as well that we can take a look at so with these three machines here let's take a look inside see if any of them work look at what they're all about and just see what's going on because as I said I Googled and I found nothing about these machines and I mean nothing so without further Ado let's get right to it [Music] thank you we'll start with the machine that was on the bottom of the stack so you'll notice some blue painters tape on here and that's because the front panel and actually all the screws are pretty much removed from this thing I don't really know why someone removed the front panel you don't need to take this off to get the computer apart the top metal lid actually removes or has screws on the sides in the back and then that comes off leaving this behind and it's actually firmly attached to the front of the chassis here now looking at this front panel it's a little bit yellow the other machine the one that was in the middle of the stack actually is the least yellowed of all has a key lock right here we'll take a look at the key in a second because it's kind of interesting there's that Leading Edge badge we have a little hole there that's for the reset button and a hard drive and a power LED for the drive Bays actually has three five and a quarter inch openings which is one more than the IBM 5170 which this machine is definitely a clone of now the middle machine in the stack actually has a blank plate right here to cover up the bottom opening and is actually form fitting to this plate here has the angle and everything exactly right so that's kind of cool and two exposed dry Bays is exactly what the IBM 5170 does have flipping displayed over gives us an idea of what the original color should have been like the non-yellowed color would have been this beige that actually pretty much matches the top of the case perfectly behind that front bezel you'll see here that there's another internal five and a quarter inch Drive Bay actually has space for two half Heights or one full height which is what's in here right now we have two floppy drives that are mismatched and an empty Bay at the bottom I can see that all of these use Drive rails to actually install so this one has missing Drive rails obviously there's no way for us to install that third device on this case and there are little metal plates here that you can unscrew and that's what holds these drives in all of these are actually held on this computer although on some of the other machines that our drives are kind of loose and floating around down here we have a little PCB and this has the reset switch and the two LEDs for the front panel we will take a closer look at this key lock in a moment I have the keys but they are in one of the other machines so I don't have them handy other things on the front is a speaker Grille and you'll notice here the metal is very thick and actually that kind of brings me to the whole point that this entire computer is incredibly heavy and really well built everything is solid metal and everything is super super heavy now looking around at the back this machine does have a trim panel it's made out of plastic and it is quite yellow which is why it's that color but underneath is that thick metal chassis that this whole computer has starting over on the left side we have the power supply here power switch not the chonky red one that you have on the IBM systems but still very satisfying IEC input IEC output to hook up to your monitor cooling fan and here's the sticker that tells us all about this machine so as I mentioned at the intro model number mp2400l system unit 115 volts at 6 amps that's a significant amount of power there's a serial number there four zero zero three eight one so I don't know if they actually started at 4000 or this is a very low sequence number and the date December 1985. also notice right here above the date it says 20 kilograms I think it's about 44 pounds which absolutely seems correct this thing is a beast I'm not sure I've ever moved around a heavier desktop computer especially like this thing has two floppy drives and a full height hard drive in it and a bunch of expansion cards all of that that just adds tons of weight next up notice this hole right here actually goes inside the computer I have a feeling originally there was a battery pack that was on a little carrier that was attached with this one screw and you could actually service the battery without taking the whole computer apart next up there's the keyboard connector most likely just a normal at keyboard and then we have 10 count of 10 Isa slots that is by far the most I've ever seen in any normal consumer off-the-shelf type system definitely more than the eight that was included in the IBM 5170 and that 5160 and all those types of machines the fact that IBM only put eight slots on their machines pretty much cemented in place that number of slots for every machine after that all the Clone cases and whatnot keep in mind this machine came out in 1985 which is only one year after the 5170 came out so I think this is a pretty early at clone therefore they probably tried to do some things a little bit different here to I don't know differentiate themselves from IBM to make this machine appealing to potential buyers all right let's start with this machine by popping the top off and we'll take a look inside we obviously have three other machines or two other machines I'm sorry to look at and I think these machines are all essentially identical although it looks like the components that are inside aren't all the same so there's a little bit of a hodgepodge going on but let's pop this cover off okay so normally like I said the front cover stays on the plastic trim and the metal cover on the top actually slots into that so the way the cover comes off normally is you take the screws off the side both sides and then you take the screws off the back and then this cover simply slides backwards and then you just lift up on it now that the front cover has been removed take a look at this key switch when you lock the system this metal plate actually rotates up towards the top cover and interlocks with it to prevent easy removal of the case obviously within the force you could probably get it off and this switch right here is how the system knows it's in the locked or unlocked position most likely the only function of this is while it's in the down position like it is right now which is the unlocked position you can actually type on the keyboard and it's very typical for these systems that while it's in the up position or in the locked position you can't type on the keyboard this is very much the same as the key lock here on the IBM 5170 at when you lock this you can't type anymore and I think this interlocks with the case as well to prevent easy removal the problem is this entire assembly here holding the lock is just plastic so I'm sure it would break pretty easily if you needed to force your way into the system compared to the Leading Edge this entire assembly is thick strong metal so it's not going to break that easily now with the top cover removed right away we can see that there are a good number of expansion cards installed in this machine in fact there are seven which would almost max out a regular IBM PC although in this machine because there are so many slots we still have extra space available for additional expansion cards we have the chunky full height hard drive there's the tops of the disk drives and there is one of the biggest power supplies I have ever seen in a PC like I don't have small hands this thing it's really big and interesting as I'm noticing here there's a metal plate right here oh this is the little battery cover that goes on the back so someone was nice enough to just tape that in looks like it's painted metal and would probably match the color of the unyllowed rear plastic trim okay I think the first course of action is to take out these cards one by one and let's take a look at what they are exactly so this system uses normal Phillips screws so nothing torques or anything like that and right away I'm noticing that this card is a bit interesting because it actually is a double width card when it comes to the slot cover here this is giving us a clue as to who actually manufactured this machine Mitsubishi Electric Corporation and it's written on all sorts of components inside this machine so even those Leading Edge on the outside it is absolutely made by Mitsubishi on the inside now this actually jives is what we know about Leading Edge because early on their machine the Leading Edge model M was an 8088 system so like XT class and it was made by Mitsubishi in fact it had a very similar model number to this I think it was like 1760 or something like that this is off the top of my memory there are photographs of the original model M machine I don't think it's sold in really big numbers but definitely sold enough to have some information about it but it wasn't long after that M version that the D version was released the model D for Daewoo and that's a Korean company the model D was actually a machine I featured on a previous episode of PC archeology so I'll put a link down in the description below if you haven't seen that video but that machine was just a normal 8088 unlike this computer which is definitely a 286. now looking at this board closer it says subsystem board here but what gives away what this actually is is I'm pretty sure there's a cereal board because we have two serial uarts here these are 16 450s the rest of this board is populated with just a ton of TTL logic even though you might think this is Ram or something like that these are bus transceivers and whatnot so I have a feeling this is also a parallel board if we look here yes there we go we have two serial ports and a parallel port all right the next Port that's installed in this system is a Microsoft Universal pointing device adapter also known as a bus Mouse adapter and it has the standard bus Mouse connector right there and not a whole lot to say about these and the next card we have in the system is some type of network adapter and I wouldn't be surprised if this is like a token ring or something like that it does say three con corporation on the back we have coax and we have a 15 pin aui connector so for transceiver now the dates on these chips say 1987 but yet the date on the subsystem card and the motherboard do say 1985 which matches that sticker in the back so this was definitely added after the fact I like this Sony static Ram chip that's it's right here with the big Sony branding on it I noticed down here there's a little neon tube almost certainly this is going to be used for some type of surge suppression on the coax line to help prevent damage to the circuits here I don't really recognize this card I have to say I've never seen anything like this so I'll have to look that up and in editing insert a little extra to say what kind of card this is here's the next card in this system it's an AST Rampage at I love the name Rampage it's a little bit of a pun there this board is equipped with 256k chips so eight of these well there's nine for parity is 256k so right away we have one megabyte two megabytes of memory now as it's typical for these types of cards there are some switches on the top edge here that allow you to set the card up because you need to tell this card where to start its memory 286 Systems Support a maximum of 16 megabytes of RAM and you can have like one megabyte on the motherboard or even four megabytes so a card like this if the motherboard has four mags this needs to start its additional two Megs of memory at the four Meg worker to bring your total memory up to six megabytes I found these boards in the past to be pretty reliable and there's good documentation if I recall about how to set the switches up because without that it's pretty much impossible to use these cards so if you have a ram card like this but it's not one of the more famous or well-known Brands it can be very difficult to get it working because there's a lot of switches on here and to just do it by trial and error would be next to Impossible next up out of the system we have a VGA card this would obviously be an upgrade this was not installed in this thing when it was new 1988 day code right there in 1988 date codes on the ROMs Western Digital corporation on the ROMs there even though it is a paradise pvga chip there looks like the RAM on here is four bits wide so we have 64k 128k this is a total of 256k and this right here would bring it up to 512k so a decent card with some capabilities for some extra high-res modes like with 256 colors in 640k and stuff like that but on the back plate here you can see it just has a normal VGA connector and it has some dip switches and luckily I think these are relatively well documented so setting those switches up properly is actually possible all right so the next card that's in here is a floppy controller and it's actually kind of a cool one because it's got an edge connector here a pin header another pin header and on the back we actually have an external floppy Drive connector as well I think this is a total of 37 pin connector it's the same one that IBM used to facilitate external floppy drives on the original XT the original XT and the original 5150 if you didn't realize could support up to four floppy drives this is something that really wasn't carried on from the at on IBM kind of ditch support for this but it seems like this card and potentially this system could support up to four floppy drives now it says copyright 1987 micro Solutions Incorporated and the compata card I'm curious what the original floppy Drive controller was in this system because clearly this was not that maybe one of the other systems has it still and we are down to the last card in this system so this is a Western Digital MFM hard drive controller the WD 1003-w-a-h I've definitely had some of these in the basement before they're very good cards they're very reliable there's 1986 date code on that ship there's some other ones they're 85 so there seems to be an early 86 card 16-bit card of course means that this needs to work in an at because this does not have its own bios on it even though there's a little bit of a sticker right there that means that you have to use the onboard bios on the motherboard to set up the hard drive type which is how IBM did it on the 5170 so this is really just sort of a copy of that original card well that card on the IBM had a floppy controller on it as well this card copies the entire command set that IBM standardized on their card for at cards and then the floppy jar controller is obviously separate now one thing about MFM hard drives you just see the hard drive right there you have to be aware of is that often you need to be matched to the right controller for the data to be read off the hard drive not to mention the heads and cylinders have to be correct as well these don't have the sector translation of newer IDE drives so they're not for giving if you don't have the heads and cylinders right you got to get that pretty much exactly right now I found typically on ATS when you're using 16-bit cards all these cards are pretty much the same like they're all a copy of that IBM original card that came out in the 5170 so these generally work interchangeably it's with the XT that things are much more well let's just say not compatible with each other so if you have a working hard drive and an XT and you plug it into this controller you're not going to necessarily be able to read the data and you have the low level the hard drive first before you can use it and you'll lose any access to that data that might have been on there I think what I'm going to do next is just remove the hard drives and the floppy drives from the system it's going to make it a little easier to handle because it will be quite so heavy these are the little plates that this system uses to hold the drive rails in or keeps the drives from sliding out of the machine and the design is kind of cool because all you have to do is loosen the screw and they actually kind of tilt downwards you don't have to take them off the machine entirely like I just did and that allows you to take the drives out easily without misplacing these little metal plates because frankly that was a common issue on a lot of these systems that use these little retaining clip lips if you took them off and just misplaced them then the stuff would just slide around in the case and it wasn't ideal so I'm going to put this one back on there so they're all on there now they're just turned sideways now there's a good chance that this hard drive is not parked so I'm going to be very careful with it in fact I don't even know how these machines were handled before I got it they probably were banged around quite a bit on the top here flag track logs this is the bad heads and cylinders and at some point someone added an extra one there so you low level the drive and it would tell you oh you have some bad sectors you just type those in that way dos wouldn't even have to see those they would be kind of marked out I guess in the partition table or whatnot before dos even tried to format it now here's something that's interesting this has a compact sticker on it so this obviously came out of a compact original and it's a magnetic peripherals Incorporated hard drive which was a controlled data Corporation out of Oklahoma City Oklahoma and I'm noticing here the type 12 sticker someone crossed that out and rode 14 on it so we'll have to try 14 first to see if we can even read this that's of course if this drive even spins up I'm going to slide out this floppy drive here I've unconnected the cables on the back there's the drive rail that this system uses pretty run-of-the-mill I think any Drive rail for any type of at type system which is a good thing because I actually have a STL file I can 3D print if I need to make more of these if I want to Max this thing out with more disk drives looks like here under the drive rail we have a Mitsubishi sticker so this would be the original floppy drive that was on the system so that's interesting a black drive would have been what came with this even though it has a whole beige color scheme going on I can't make out the model number this drive because it's covered up by the drive rail but I would say this is almost certainly going to be an 80 track drive so 1.2 megabyte and it moves freely so there's a good chance this drive works perfectly and let's slide out this second drive here and this drive says Toshiba Corporation 6882e1j I don't recognize that model number I don't really know these Toshiba drives that well and here's the floppy drive it's a it's a floppy drive it probably works these things are dead reliable of all 1.2 megabytes on this one let's take out this power supply because we're going to take a look inside and see the condition of it not to mention try to do a little testing on it first don't necessarily trust it to work right off the bat and not damage the motherboard although I suppose if it does we still have two other power supplies and two other motherboards that we can test with but I'd rather not sacrifice a motherboard if I don't need to now one thing I can definitely tell I know we haven't taken a close look at this yet is that this motherboard is not a standard at motherboard therefore this motherboard is not going to work in any other case and a regular at motherboard is not going to work in this case looks like this case can only accommodate this motherboard and this power supply this power supply is also very very non-standard and the reason why I say that is take a look at the power connectors on the motherboard here this looks almost like an apple II connector of some kind yeah this is very similar to an Apple II style power supply connector and then it has an additional connector here and this would be for the additional voltages that are carried to the motherboard especially the ISA slots this one here is almost certainly 5 volts in ground which is why it's red and black but Isa slots get 12 volts minus 12 and minus 5 volts as well which is almost certainly what's carried over this connector right here so we get a total of four Molex connectors on this thing which is not very generous considering there are actually five Bays there you figure there should be at least one for each one of the Bays but I guess they expect you to use a splitter and look at this after I remove the ribbon cables I'm noticing that this actually has onboard floppy controller on the motherboard perhaps the onboard controller on this thing has gone bad and they were able to disable it and switch to that expansion card so to get the power supply out it appears to slide forward now they took the screws out and then it comes out so there it is this is what I'm talking about it being a little bit non-standard with this big overhang going on right here now the original IBM 5170 also had a similar design the proportions are a little bit different but the overhang on the 5170 is a lot smaller and a lot of at cases after the 5170 they copied the way IBM did it exactly they didn't kind of do their own thing like Mitsubishi did with this thing on the side of the power supply here it says pc13wa and it has the output voltages which as we expected 5 volts minus 5 plus 12 minus 12. the usual stuff I like how Mitsubishi wrote three kilograms right on here like hey by the way yeah it is a really really heavy power supply here we are taking a look inside the power supply it's a multi-board design it's also upside down uh the top is this part on the bottom here the cover comes off really easily you just take the screws off and it just slides off this top board here seems to be the mains input and the high voltage DC generation so this takes the mains input and it rectifies it and then puts it through these large capacitors right here so that turns into like 300 volts DC here in North America or 260 or whatever it is and that sends it down to this board here where it's converted then into the regular DC voltages which works like a pretty run-of-the-mill power supply I see nichecon caps on here this thing would be early 80s so these are going to be top quality like really good quality caps I don't see any Reef as I can see there's some filter caps over there and they're the type that generally don't go bang like the reef is do but they can get leaky which can cause your gfis or your rcd Breakers to trip depends on how they're configured so if that happens I'll have to take this apart and get those out of there and replace them with some something a little bit more modern and a little more safety appropriate but right there that's the bridge rectifier so yeah pretty interesting power supply but everything looks pretty good in here and looks very high quality so I don't think this thing is going to have any problems in fact check this design now this is the high side that's the low side we have a really nice separation distance here with a little Mark there and then we have all this extra stuff here for extra current capacity that's pretty cool for loading these things up I'm going to use a couple light bulbs here and this thing can do 23 amps at 5 volts so that should be no problem at all I'm going to use four Nails total to try to avoid the problem I had last time when we were testing the Apple II power supply where the nails were getting hot and I was getting that voltage drop all right everything's connected I have the multimeter over here I'm going to turn this on no breaker tripped or anything like that the power supply is off the switch is off right there so let's turn this on and see what happens all right we're getting 5.15 volts on the 5 volt rail let's check the 12 volt rail using this multimeter here we're getting 11.9 is that readable yes it is 7.9 okay so that's okay I'd like to try to bring the 5 volt down a little bit 5.14 a little too high for my liking I could see a potentiometer right here and I have this uh ceramic adjustment tool so it's completely non-metallic we're going to see if we can get in there and tweak this oh yeah that worked so that is totally changing the voltage there so we're at 5.06 now 5.15 let's just turn it down a little bit how about 5.07 seems like a happy medium right there we have plenty of load on this power supply right now I let the power supply run for about 10 minutes with a hard drive hooked up to it and those light bulbs and nothing bad happened so I gave it a dusting cleaned out the inside and put it back together let's turn our attention back to the chassis here you might be noticing that there's a blink on here now well I was looking around the case and it was actually just stuck down here behind the slot brackets here and I pulled it out it looks like it fit on the front so with that attached to the front see if this actually works I think it does all right so that's kind of cool I wonder why the other computer has a plastic blanking plate that goes into these little notches here on the front bezel as opposed to something that's metal that you screw in but hey that's better than nothing isn't it I'm incidentally taking the faceplate down it has these hinges that go along the front that go into the metal chassis and one of them is broken off but just one of them and it definitely does get screwed into the front chassis so that should hold it on with no problem in addition to the front blanking plate that I found I also found this which was another set of the keys that go with this machine now I said I already had one set and I did notice that they actually are interchangeable so the one set that I did already have worked in all three of the machines but now that I have another set of these Keys take a look at the key it actually is half decent when you put it in there it has a nice firm positive action and there's that mechanism that latches the top cover as I talked about earlier in the video and you can pull this out so you can leave this locked and take your key with you and then someone shouldn't be able to use your computer nor take the top off until you come back close that down and then you're good to go this is really what I wanted to show off take a look at this motherboard we have one Meg of ram it looks like it came with 512k and then we have an additional one megabyte and then there are those 10 Isa slots now we actually only have nine installed in the board but you can see that there's a footprint for an additional slots you could have all 10 and all 10 of them can also be 16-bit Isa slots right here we have the 286 processor this is the type of package where it's a little flat ceramic package with gold contacts and it's held down by this metal little cover here we do have a math code processor and this is the dash 8 variant so I think that means eight megahertz you should be able to get a look at the unusual power connector and the other power connector here that goes to that proprietary power supply and then take a look at the battery on this thing I think that little metal cover that I talked about wasn't actually for a battery holder or anything like that looks like it was to access some dip switches right down there those are the dip switches so that's the cover right there and now you can actually access these switches but I think we really lucked out with these batteries because if I pull this thing off the motherboard here sealed nicad battery 3.6 volts 150 milliamps Japan storage battery company this could have been really ugly and luckily it wasn't nothing leaked on this battery and I just quickly looked at the other machines and they hadn't leaked either so how good is that this could have been very very destructive for this machine what I did do is I chopped off the cable from that battery because it's a little bit of a non-standard connector so I'll just leave this plugged in the motherboard until we're ready to connect up another battery this motherboard has some jumpers like here's a few right here but unfortunately there's going to be no way to figure out what they do because there's just no documentation at least for the Leading Edge version of this thing and moving back to this part of the motherboard there's a few more jumpers we have a bunch of gals or Pals or something like that so these are custom chips and if they're dead the motherboard is definitely not going to work luckily I think we have enough Parts here to at least make two fully functional machines and I think the extra machine will just be Parts because that carcass machine never had a lid or front panel or anything like that with it over here as I mentioned the onboard floppy controller lives we do have some barge wires by the way that that make their way around the board but for Hardware configuration options like the floppy Drive controller it's almost certain you have to set these switches to enable or disable this you're not really going to see very well but down there is the floppy Drive controller to 765 which is a very standard part for the PC this computer just appears to be a really well built but yet somewhat customized IBM PCAT clone well I mean to be honest for all we know this isn't even fully PC compatible I guess we'll find out when we try to actually get it booted but the fact is that it has regular Isa slots and has normal PC style cards in those slots that we just took out like a VGA card makes me believe that this thing is going to be a hundred percent compatible there the BIOS is really going to be the main part with the IBM PC one little tidbit I want to mention about this machine I noticed when I went to put this face plate on here is that the screws on this thing are entirely metric that is completely different than IBM who use Imperial threads and to this day every single PC case you buy when you go to like screw a card in or whatever is entirely using those same threads as the very first IBM PC the 5150 from 1981. so that means if you get one of these don't just use an imperial thread and jam it in there just get the right metric screws and you'll be good to go I have talked long enough it is now time for some testing the power supply is back in the machine I took the computer outside before I put the power supply in gave it a little air dusting so it's a bit cleaner although if well this thing is still very dusty inside it would need a proper wash we're going to use my post analyzer card here just to see if this thing works I'm not fully expecting this bios here that's on here to actually support postcode so if this doesn't show anything it doesn't necessarily mean it's not working but we should be able to see some activity here with the LEDs and I have the power connected to the power supply and here we go okay we're not getting any beep codes of course we're not seeing any postcodes but that might be okay I would expect to keep uh yes there's Signs of Life everyone we have beat codes definitely the postcode analyzer is not helpful when it comes to the display there but at least the LEDs show we have good power rails and let's hit the reset button there we go that's normal for reset you get one LED off another one on and we let go and I think it's going to give that that same error again there it is came came much quicker that time all right this is a great sign I'm gonna get the VGA card we're gonna grab a monitor and hopefully see this thing come to life and let's see if we get an image hit initialized it appeared to initialize oh it says Ram R test okay FDD test CMOS power failure continue press F1 you probably can't read any of that all right this thing appears to be working unfreaking believable all right so let's put in the XT IDE that's exactly why I have cards like this because you don't need to go to the CMOS settings or do anything to get the system to boot off of it card is in let's see if it works now hopefully hopefully that is readable on the camera it says F1 to continue oh yes all right this is a good sign everyone let's see how fast this computer is the BIOS manufacturer says Mitsubishi did they actually reverse engineer their own bios or was this somehow licensed from IBM or something like that so there it is 8286 at machine a20 is active we have an 8287 math code processor 512k of ram it somehow thinks we have 13 000 K of extended memory so that's a corrupted bios that's doing that and this is what we all want to know how fast is this computer I'm predicting eight megahertz 8.01 megahertz 1493 dry stones and then the math speed is 263 000 wet stones or 40 times that of the IBM PC XT let's run the landmark speed test here see how many weight States we're running at 8.9 megahertz so I'm going to say this has the exact same waste configuration which I think is one weight State as the original IBM PC at if this thing were running at zero weight State somehow a very fast Ram or whatever then we would be getting more like 11 megahertz or so it makes sense that's not the case though because this thing was from 1985 which is only one year after the IBM PCAT came out and in fact remember that the original PCAT was only six megahertz I'm not sure when the 8 megahertz version of it came out but this thing from 1985 was already faster than the original PCAT and one megabyte was possible on the motherboard while the original PCAT 512k was the maximum that it ever had on the motherboard now it is unusual though because it is showing that we have only 512k of RAM and definitely one megabyte is installed on the motherboard but I'm assuming the configuration of this thing right now and this is kind of unfortunate because of the way that the dip switches and stuff are we don't know how they work it's currently probably set for 512k and conventional memory and then the rest on the motherboard here the other 512k is probably extended memory which is in the higher bank usually well on clone motherboards there are ways to configure it where your conventional memory is 640k and then the little 384 is extended memory I'm going to move over to one of the other machines but before we do that we are just going to take a picture of the dip switches on this machine and the jumpers that are in here and back here as well so I have a record of the way this one looks compared to this machine which as you can see has been stripped for all of its cards it just has the original Mitsubishi dual serial parallel card and on this machine there is no floppy cable over here which means it must be using the onboard floppy controller so that's a good thing these are just hard drive cables and this this is what I was talking about that face plate on this front panel notice it's actually in the plastic and there's no metal one behind there so it looks a little bit better because it matches the lines of this case this one's also a lot less yellow than the other one we were just looking at although it definitely has some yellowing it is much less interesting that this one has a beige disk drive on the top I'm going to get this front panel off so we can slide this out and the hard drive to take a closer look all right faceplate is off there are three screws along the top holding it on and they are plastic type screws not some kind of metal insert metric ones we can definitely see that this one is yellowed a lot less because there's a little bit of yellowing but compared to the inside it looks basically the same I'm intrigued that this has a metal cover over the hard drive front must be a shielding thing I'm presuming whoa okay underneath there is a full-on faceplate and I guess this cover is actually what holds this in place the cables have been freed and let's slide this thing out of here oh heavy Beast it says type 3 cylinders were written on there this is model number CM 6640s from computer memories Inc okay here's the floppy Drive this one is a Fujitsu limited Drive model number m2553k so I don't know if that's 1.2 or 360 but I am assuming it is oh look 96 track per inch okay 12 1989. so someone was doing testing on this at some point that's pretty cool looking inside the computer here we have a mega amount of dust that's kind of gross although overall it's less Dusty when it comes to that fine dust that was on the other one and other tidbits about this no math co-processor everything else looks the same in here though I am going to take a picture of the switches and the jumpers just like I did on the last one here's something interesting the manufacturer date on this is July 1986 and the serial number is zero zero one zero two zero the other one started with a four if I recall the serial number that is and manufacturing date was in 1985. looking at the dip switches on these two machines they are configured differently all the jumpers on the motherboard are the same but the dip switches are different that's a good sign I'll make sure to document this and here is our final machine this is the carcass machine that I had on the top of the stack at the intro this one has two hard drives in it and this black floppy Drive which I'm assuming is the original Mitsubishi one it also has a somewhat full complement of cards although not exactly the same so let's take a look at what's different here on the back things are similar to that first machine four zero zero two two seven and a manufactured date of December 1985. I think the main difference is this looks like an EGA cart that's installed in here as opposed to a VGA card and we have a different Ram multi-i O type expansion card installed here I also have the keys they were stuck inside this computer and if we take these out we have s727 on the left and then we have the X key on the right the one I found taped inside that other machine all right so let's try this key this is the X key here oh no it does not work in this let's try the other one on the key ring here which I'm assuming is the same nope and then these are the ones that were in the little bag that I had in this computer but nope that does not go with this machine either well here are the other two machines and let's see which of these work in which machine so that doesn't work in there that works fine in that one and this one I presume is going to work in this one and yep it does okay so two of the machines have working Keys which is good because this is the carcass machine that's missing the top cover and the front cover and was never going to make a working machine anyways so it's good to have the right keys for the two machines that can be put back together all right so first card out of the carcass machine we have a Genoa I haven't seen Genoa in a while EGA card this has 256k of ram Genoa bias 3.0-5 and there are the dip switches up down up up up however that is configured I don't know I'll have to go look that up oh and next up we have an Intel Ram Board so we have memory here which I'm assuming these are 256k chips so that gives us a total of 1.5 Megs of RAM and then there is a Serial you are a 16 450 again which looking on the back of the card there's a Serial port and a parallel port and then we have some dip switches which are going to be for the memory configuration of the system once again next up we have an MFM controller and this has day codes mostly from 85 although this chip here is fifth week of 86 so my assumption is this was installed in the machine very early on when this thing added hard drives or had hard drives added to it and you'll notice here by these cables this has two hard drives in it which you can actually see there's one right there another one right there we have another cable that was floating inside the machine this is a floppy drive cable and judging by the short length of this and the folds this is definitely the one that was originally attached to the motherboard it is no longer attached we have a nice ceramic math co-processor the 286 chip there the BIOS looks the same and we have one Meg of RAM installed on the motherboard along with this uh you know serial board that's in all three of these machines and incidentally the Masco processor in here is a dash three variant which I'm pretty sure is the one that runs at like four megahertz or something like that or half the clock speed of the system clock let's get these hard drives out of here so this first one oh I've seen this before it's a half height Control Data or magnetic Corporation the same as that full height one we had on the other machine I'm pretty sure I have a drive exactly like this and I can't remember if it works or not but I think it does it reminds me about it is it's got this plastic cover on the bottom just a sheet of plastic and this does this have original Drive rails I don't know these look like they're some kind of resin kind of interesting and the floppy Drive which already had the cable removed this looks like definitely one of those Mitsubishi drives let's get this grounding cable off of there and indeed it is it has the Mitsubishi sticker right there and that looks like the original Drive rail for this machine because it matches what was on the other machine and this hard drive here is being very stubborn with the power connector we have a message here it says good 40 megabytes originally from Andy's PC and format it for 30 megabytes I wonder what that's all about Fujitsu Limited m227d that's the actual true part number on this thing all right looks like my camera is about to overheat so I'm going to let it rest a little bit while I clean up a little so what you see on the bench here are all of the parts I took out of all three of the machines the motherboards were left in the two machines that are complete but I did fully disassemble the carcass machine here's the motherboard from it and I have the heavy heavy case here that held it all and even though it's empty yeah that weighs quite a bit I even went ahead and removed the back panel from the carcass machine this was the only part of the trim that I had left from it unfortunately a bunch of the clips broke in that process but at least I could use that on another one of the machines maybe with a little bit of glue or something if it's better condition than the ones that are on the other computers because this video is getting pretty long I've decided to go ahead and test all these components off camera or on a second Channel video I think I'll put testing these hard drives on second Channel video so if you're interested in seeing that definitely watch for it or if it's already out by the time this video comes out I'll have a link down description below for that what I want to do is take the best components from what we have here on the bench and make one really nice Leading Edge mp2400l machine and show it fully operational and working so it is time for a jump cut while I go and test all these parts and yes another wardrobe change this particular project with these Leading Edge machines is taking me a really long time to complete I think I'm pretty much over the hump and we're ready to finish up the machine now I tested all the hard drives on a second Channel video so I won't really talk about that uh go watch that video if you want to see what it was like testing out those hard drives and what the result was but I can tell you that I have one working drive that I'm going to be using in the computer today that I put together when it comes to all the other Hardware there were four disk drives and motherboards and power supplies and all that other stuff everything worked every single thing that I tested worked perfectly there wasn't even a single bad Ram chip on those Ram cards we just took out of the computer I'm actually frankly kind of shocked what I have on the bench in front of me here is one of the motherboards I took out of the carcass machine so we could take a really nice close-up look at this motherboard because it's kind of a reared one-off configuration like I said it's only going to work in these computers so you may never see something like this again and this is it the motherboard from the Leading Edge mp2400l in all of its large Glory so as I mentioned earlier we have 10 slots here and even though that one's not installed because it has that double width serial parallel card you could easily clear out those holes here and install these extra bits and have 10 16-bit Isa slots I actually did a bunch of testing with this motherboard to figure out that how the dip switches work and I have that little chart right here and I'll get to that in a second the machine obviously has one megabyte of memory here that could be configured in a couple different ways and we'll talk about that the BIOS chips that are in here are just these two and I have dumped those bios so I'll make those available for anyone who wants to check out this Mitsubishi bios there are jumpers on the board right here just like between 27 256s and 27 128s so I guess that allows you to have a larger bios if so desired these chips here though are 27 128s and we obviously have two additional sockets available for an enlarged bios maybe one that could support proper menus and things like like that in case you're not familiar it is very typical for 286 motherboards that have two bios chips like this and it's really because this is a 16-bit processor it's right under there and these are 8-bit chips so you really need two of these to work properly on a 286. now in case you haven't seen these types of sockets before these text tools 3M sockets you can actually release the CPU by sliding this backwards oh it's really stiff there and there we go it pops up and there is the actual 286 chip in there it's a ceramic flip package I think it's called there it is it's quite a beautiful package actually the gold and everything and uh ceramic on this side this is an actual Intel part as well and to get the chip back in you have to position it on the socket and I think we have to get this like that and then slide this back and it's there we go like that that holds it in place and it acts as a little bit of a heat sink as well these chips do run pretty warm now back on the rest of the motherboard I think this is a very typical chipset for the 286 we have like two dma controllers two irq controllers that are cascaded together I think that's these and these over here we have the floppy Drive controller and incidentally remember we had that one computer that had an external floppy Drive controller or sorry it was an expansion card I don't know what was going on with that because all four or all three of these motherboards have a working floppy Drive section they all just work and I'm actually not even sure how to bypass the floppy Drive controller I think what was happening was this additional card that was in one of the machines is acting like a secondary floppy Drive controller it's designed for xt's only when I look this up so it can only do 250 kilobit per second floppy drives that's like a 360 or 720s so my assumption is the internal floppy Drive controller well supports amb drive and maybe they were using the C and D drives with this or perhaps it was connected to a tape drive solution don't quite know at the top of the motherboard we have the battery connection it connects right here there's the little wires that are left behind this is very typical that it does try to charge the battery so if you're going to try to hook a battery up to this you need to use a diode there are some jumpers up here and I don't quite know what those do I couldn't really figure it out basically this is always seemingly getting the 5 volts while the system is powered up and I did try changing this jumper that doesn't seem to do anything different this is the clock controller chip though so you could remove this and replace it with one of those integrated clock chips it has its own battery kind of like a Dallas chip I had a video on my second Channel about my at5170 where I did that mod which helps make the battery last a lot longer because typically these types of solutions with the battery connected here will drain the battery relatively quickly so I do recommend if you have one of these swap that out for one of the necrowear clock chips these are the dip switches are right here I'll talk about that in a second and like the rest of this stuff on here is just pretty much standard TTL logic that's just a motherboard that is a clone of the 5170s architecture which is just basically the XT architecture extended for the double the number of irqs 16-bit slots and double the number of dma channels facilitated by cascading these chips together here and Mitsubishi just went the extra mile to add up to a Meg of RAM on the motherboard and a flop Drive controller plus some extra other small capabilities of this that are over and above better than the IBM if they had just used the standard form factor that IBM originated though like with a built-in keyboard connection then would have been possible to put this motherboard into an at or put 386 motherboards into that large MP 2400 L case for instance but unfortunately as I mentioned this thing is totally custom and this is the only motherboard that's really going to work in that case now let's talk about the dip switches I did go ahead and basically compare pair the dip switch settings which are right here on all three of the motherboards that I worked on and I tried to figure out what all the dip switches did and I did that by using actually this motherboard on the bench over there plugged into a power supply of course so I could start fiddling with the settings on here more easily than having it in the case and I actually was able to uncover some neat and interesting features about this motherboard but also some limitations now right off the bat one interesting observation I was able to figure out is that the ram is actually configurable in two different ways one way is with 512k of conventional memory and 512k of extended memory if you take a look at dip switch 3 it was on on all three of these motherboards and I represent x with on I know it's a little weird and the O is off so on on Well turns out when this dip switch is in the on position it sets up the motherboard with the 512k of conventional memory right here and 512k of extended memory well the other configuration of dip switch 3 is in off and what that does is it configures the RAM for 640k of conventional memory and no extended memory my thought is that with this motherboard right here 256 K by one chips are installed in all four of these Banks well it's actually two Banks because it's a 16-bit processor so this is Bank zero and that's bank one well in the 640k configuration I think what's happening is that this bank is configured with two to six K chips and then this bank here the Second Bank is configured with 64k chips which gives you a total of 128k in this memory now initially I thought when I set it for 640k that the other unused part of this memory here would be available as extended memory so you'd have 384k of extended memory that doesn't seem to be the case when you have dip switch 3 set for 640k you just always have 640k and that's it you have no extended memory 64k chips are actually the same footprint and it's just one extra unused pin so I have a feeling flipping that switch just ignores the extra your address line on these chips and just uses them as 64k which results in no extended memory on your 286 it's not actually a big deal that we don't have that extended memory yeah it's a little bit of a waste and I think back in the day you would have been throwing money away by putting 256k chips in here but nowadays it's not that big a deal and we can just use one of those Isa Ram cards to extend the memory the rest of the way but I actually figured out some other interesting tidbits about this motherboard that actually make it quite a bit faster than the regular 5170. one thing about the 5170 is that it runs at either six or eight megahertz depending on which version of the motherboard you have and it always runs at one weight state that means that the performance is you know pretty good but we know that when you run a 286 at zero weight states that means the processor is not waiting around from the memory to become ready or other components on the board you get a significant performance increase well it turns out that this motherboard via those dip switches has two different clock speeds well actually three different clock speeds available and either zero or one weight State and it has to do with switch one and two where there are four possible combinations and I've outlined them right here so the first configuration is when one and two are both on you get an eight megahertz system with one weight State it's very similar to the 5170 at eight megahertz the later versions of the motherboards and there's another configuration where one and two are both off that gives you six megahertz at one weight State as well which is exactly like the earlier 5170 motherboards if you change switch one to on and then two is still off you get a six Mega System at zero weight States you get pretty sizable performance increase on a system like that you're running a six megahertz clock speed but you're getting the performance of maybe a nine megahertz computer so you're actually exceeding the performance of even the 8 megahertz 5170 and then there's one final configuration off and then on where you get 7.17 megahertz it's very odd clock speed but that's what the system runs at and that runs at zero weight States and that has the equivalent of around an 11 megahertz 5170. so you get a sizable performance increase by that configuration and it appears that this motherboard fully supports that speed like it doesn't have any issues with the ram speed or anything like that running at that zero weight State the only problem that I found is that one of these machines had the dash three version of the math code processor that's what I'm pointing to right here and it really does not run properly at these higher speeds it only runs properly at the six megahertz speed because essentially the system will have the clock speed that goes to the math co-processor and that runs at three megahertz or something like that and if you try to run it at 7.17 megahertz it's actually overclocking or eight megahertz for that matter overclocks the Matco processor and it will not work all right we're not quite done with the dip switches uh dip switch 4 I could not figure out what that one does doesn't seem to really have any noticeable difference when I switch it on or off and the same goes for switch eight and I thought that maybe was like disabling or enabling the floppy Drive controller but that does not seem to be the case either way these just don't work five and six seem to be something to do with the Ram size so if it's off and off it's the one megabyte configuration I think if they're on and on it's 512k and that's it like the system will never work with more than 512k and there maybe are some other configurations in there but I did try the 640k setting on uh the jumper over here what was it jumper number three and I tried fiddling with these and never could I get any extended memory so it really feels like this particular motherboard if you have the 640k configuration is expecting those 64k chips and the other bank here and there's no way to get that extended memory at least that 384k of extended memory and if I and then the final switch is seven and I wrote must be on if it's on everything is working fine if you turn it off when I type on the keyboard you get gibberish so my assumption is that maybe this motherboard was designed maybe for like the Japanese Market to support some kind of Japanese style keyboard that had different scan codes it it's not XT because I tried an XT keyboard and that doesn't work either it just doesn't seem to work properly but when you set that to on everything does then work properly and that's all there really is to say about this motherboard as I mentioned all three of them work absolutely perfectly and they're pretty fast and when you set it for 7.17 megahertz at zero weight States it's really quite speedy and for 1985 that's a big deal compared to what IBM was selling with the 5170 for probably substantially more money and that would be running at six megahertz with one weight State and yeah this thing is basically blowing that computer out of the water maybe almost twice the performance in that zero weight stay config pretty cool okay the final machine is coming together what I've installed in here is of the original serial parallel card I have a video card temporarily in here I'm going to put the EGA card into here so I can use a CGA slash EGA monitor I have both of the ram expansion cards in here so there's the AST Rampage and the Intel above board this is is a total of 2.5 megabytes of extended memory plus that 640k that's on the motherboard with that dip switch set and then I do have an MFM controller card in here I have that the big one installed in here and the full height hard drive in here which is working I've also gone ahead and installed both of the black Mitsubishi five and a quarter inch disk drives because these are definitely the original drives that would have come in this computer it's super duper unlikely that they ever offered a three and a half inch for this machine at least wow this machine was being sold in 1985. unfortunately I've run into a little bit of a problem when using this MFM hard drive on this machine I'm going to power up the computer here and I will show you what the problem is so it takes a little bit of time to boot up the machine because it's counting up all of the memory so that's the 640k plus the 2.5 megabytes of extended memory and right now it's booting off the floppy drive I have a 360k boot disk in there now it goes without saying that machines like this need some kind of CMOS setup and there is nothing in the Bios to do that built in this machine you have to run some kind of a Dos utility to do it so I have G set up on this disc which is my go-to program for doing these types of things on machines like this that do not have their own CMOS setup I actually went ahead and installed new clock battery in here and I used Ron's computer things little boards he sent me on a mail call episode to install two cr2032s in series so we get about six volts and there is a diode on that board already so those are not getting charged by the motherboard which means this thing retains all of its CMOS settings when you power it off and power it back on and you can see there I have some time and date stuff entered in along with the base memory 640k and the 3.5 megabytes of extended memory and I do have the math code processor installed in this computer I have the dash 8 version so this thing is running at that 7.17 megahertz with zero weight States and the math Co processor but we have a problem I need to go to number four here for the hard drive C so I can configure this MFM hard drive and when you do it comes up here and it says press right or left Arrow to select a hard drive type and in fact there is some even help to tell you that that is what you need to do but unfortunately when I push left or right it just beeps there's absolutely nothing I can do to set anything in there my assumption is the BIOS that's on this computer must be somehow incompatible with G setup and there's no way for me to configure the MFM hard drive in here so at this point I'm totally stuck there's no way for me to configure this MFM hard drive not unless I probably swap out the BIOS with a a different type but to retain the originality of this machine and run the Mitsubishi bios I can't do this unless I have the original setup disks that came with this computer and let's be honest I can't even find a mention of the mp2400l on the internet let alone documentation or setup disks so I think at that point well there's really nothing I could do for this and I'm just going to unplug it leave it in here and for further demonstration I'm just going to put the XT IDE in here and yeah that's kind of lame but that's what we're gonna have to do we'll take a look at that the machine is finally finally back together the way it would have looked come out of the coming out of the factory other than the fact the front panel's a little bit yellowed this is the less yellowed of the two that I had there are some scratches on the cover the top cover and the plastic here obviously these machines were banged around and sort of mistreated before they got to me but overall I cleaned up cleaned up really well looks really good and um yeah with that big hard drive still in there it's a very very heavy machine let me get a monitor hooked up to this thing let's see it in operation and there we have it it's like the chunk Master 2000 has entered the room yeah look at the size of that large keyboard compared to the computer it's kind of like dwarfing it a little bit and that and the 14 inch 1084 monitor looks kind of puny sitting on top there let's power this thing on of course this computer comes from an era where you just needed one fan and it was loud and blew a lot of air and that kept the whole thing nice and cool it takes a moment to boot up Ram R is the conventional memory being tested the first x40k and then Ram p is the extended memory which this machine has 3.5 megabytes so it takes a little bit of time let's run speed 600 on here and let's look at how fast this thing is actually going so it's currently set for 7.1 well 7 megahertz or 7167 megahertz at zero eight states gives us the equivalent speed of around almost 11 megahertz we have the math code processor which is still running at half speed oh thereabouts I don't know 7.43 megahertz and the video speed dots slow because this is an EGA card in EGA it's always slow as a comparison I booted up my 5170 it is overclocked to 8.9 megahertz and the CPU speed here in Landmark speed test on the 5170 is 9.8 megahertz meanwhile this is getting 10.8 megahertz so this overclocked machine isn't even as fast as this one running at 7.167 megahertz let's try Planet X3 and EGA mode you can hear how loud the speaker is right [Music] yeah it's a pretty loud speaker it actually vibrates the entire front of the machine which is kind of cool and yeah I mean this thing performs well exactly like you'd expect a 286 to perform which is pretty good and I mean considering this only came out a few years after the original PC and then the pcxt processor was a giant step forward over those machines and there you can see how much memory this thing has so that 640k of conventional well 639 for some reason and then the extended memory 3584k for a total of 4223 kilobytes awesome then we're looking at the chalk Master versus its original it's grandfather right there the IBM PC 5170 it's pretty good I think the styling on the IBM is a little nicer especially because of the painted front no yellowing or anything like that and it's so large compared to that thing but I guess bigger is better and your money paid for a giant heavy machine that's definitely much heavier than the IBM so there you go and frankly I cannot deny the good quality build on this thing all three power supplies worked all three motherboards work all the components worked all the ram worked everything just worked even those original floppy drives there just pretty damn awesome boy I really need to do something about this reflective material on the walls here really bothers me how bright that is from the studio lights there anyhow it's time for a conclusion I'm pretty impressed by this machine the Leading Edge mp2400l it's somehow unknown to the internet and yet quite a nice machine really nice machine I would love to hear from any of my viewers who remember this machine either you had one yourself before you saw them in stores or something because I'm just so surprised again that there's just no information about this machine anywhere on the internet kind of goes back to that video I did where I looked at all those weird cards and stuff and how so much of that stuff is just there's just nothing no information and and we have an entire computer here from a company that sold lots of computers and yet nothing anyhow if someone in the future is watching this because they found one of these and they were looking for information on those dip switches for instance well hopefully the information I showed in this video can help you out and I do have to add one thing as well anytime I work on 286 error machines especially ones that are early examples of that like this or my 5170 right behind me it's a pain in the butt these things are just difficult to work with and I think it's mainly because they don't have that built-in bios and it's just buggy and freezes and weird things happen and that g setup program is just so difficult to use there's so many issues you run into it just makes everything you do on this thing take that much longer so I've alluded to this in the video several times but I've been working on this video for a long time I started before I went to VCF Midwest and it's just been a Non-Stop Endeavor to try to get the hard drives working and the cards tested and all the other parts and while it was long at least it's gratifying to have one really nice clean machine out of this and and in fact I'm pointing over there you can't see it in the big mess over there but there's the other machine that second one that can be assembled into a fully complete machine although it's going to have beige disk drives because I I stole its black disk drive for this machine but it will be assembled and I already have someone I'm giving that machine to who said he's been looking for it through 286 machine for a while now so there you go hope you enjoyed this video about this unknown machine definitely comment down below if you have thoughts about this machine and all that good stuff huge thanks to my patrons their names are scrolling off the side of the screen over here if you want to see your name there or at the beginning of this video you can do so at the link in the description below my patrons get early access to videos plus behind the scenes content I do little weekly updates and I've even done a live stream already that's exclusive to my four dollar up tier on patreon I guess that's going to be that so if you like this video a thumbs up if you didn't know what to do and stay healthy stay safe and I'll see you next time bye-bye [Music]

Channel: Adrian's Digital Basement

Views: 104,007

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Id: J9Gia_CcLms

Length: 61min 52sec (3712 seconds)

Published: Sat Sep 23 2023