173°C Hot! IBM Model 50 Restoration
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- Опубликовано: 6 окт 2024
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UNI-T UT61E Auto Ranging Multimeter
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PinePowerPSU
TS-100 Soldering Iron
AMTECH NC-559-ASM Flux
Kester 951 Flux pen
MaAnt Grinding Pen
Multicore 60/40. 0.38mm and 0.5mm solder
TL866 II Plus Programmer
RIGOL DHO800 70MHz four-channel digital scope
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Music by Karl Casey @ White Bat Audio
15:51 - Hehe, I like the Super Mario sound effects you added in there!
It felt like I scored for every damaged screw I got out of that drive! :)
The resistors in the hot power supply appear to be wire wound resistors which are designed to withstand very high temperatures - often rated for up to 300 degrees Celsius It is very likely the temperatures you are seeing are normal for that power supply design.
The resistors are probably part of the regulation circuit are likely intended to dissipate a significant amount of power which is why they were soldered in such a way to sit quite a bit above the PCB to protect the PCB from the high temperatures.
Interesting, thanks for sharing
I agree
Seems kinda poorly thought out since it still melted plastic parts.
indeed, back in the days it was normal to have that kind of solution to regulate a voltage. Nowadays there are much better solutions of course. I did rebuild the PSU of my signal generator as it was regulated by zeners which were burning hot! So as @gemedetvideo says, probably nothing to "worry" about :) (Well, the melted plastic maybe...)
@@tony359 Ah, yeah, the plastics. I wonder what happened to the guy who used to work in those melting plastic fumes back in 1987 :)
Wireround resistors like that do get very hot so probably normal. The melted plastic bit is probably because the resistor is in slightly the wrong position.
I noticed it was slightly at an angle and bent it in the other direction. However, I'm not convinced it should get quite that hot
On the dirt - my elementary school computer class had us open up and disassemble machines a little newer than this - probably 486 units. They were donated from a coal power plant. Disgusting was an understatement. I’m almost surprised the machine didn’t spontaneously combust from the coal dust.
Dusty or not, I'd happily take all of them :)
That PSU connector is hilarious. Even Apple would've been jealous at how proprietary it is.
I have my "PS/2 Authorised Maintainer Certificate" somewhere. It was a one or two day course on how to use the diagnostics to replace the various FRU's when the systems has issues 😀
A model 50 was also my first PC of my own, so I always like to see someone fixing one up. It was quite late to still be using a 286, especially without a sound card, since we already had a 386 as the family computer for a number of years.
Fast forward to sometime around 2008 and I came across someone selling a bundle of 3 model 50s on eBay. Unfortunately I missed out on the auction, but I messaged him hoping the buyer had pulled out. I thought it was a long shot, but I got a reply. Surprisingly, the guy had another 3 machines that he was going to sell off anyway, so we made a deal and I bought them from him directly. When I was picking them up, he told me that the hobby of collecting vintage computers is a deep rabbit hole, and these might be the first of many vintage machines I collect. I didn't believe him at the time, but turns out he was right!
Out of the 3 machines, one power supply was working and two were dead; one planar (that's what IBM called their motherboards) was working, one had a shorted power rail, and the third just didn't work. The CPU on the last one just got really hot, and when I tried to pop it out, a bunch of the pins were left in the socket. Between them they also came with the usual 3 HDDs and 3 floppy drives, but also 2 token ring cards, and a SCSI card. One machine even had an Intel branded 386-SX upgrade board. Sadly, all 3 cases are in pretty poor condition, they all have scratches and rust, and one is a bit dented (which is surprising considering how sturdy they are) and has cracked plastic.
I figured out the trick of lifting the front of the machine and dropping it to get the heads unstuck from the hard drive back when I had my original machine. When my machine wouldn't boot, being a quick-tempered teenager when it came to unreliable computers, I tried banging the side, and when that didn't work, I lifted it and dropped it, and magically it started working! Turns out it's a well-known issue with those drives, and that's the exact fix. Until the drive dies completely.
Anyway, looking forward to seeing your Adlib card build, that will make the machine much more useful! I'm also curious if there's any modern replacements for the hard drive?
My knowledge about how hard drives work is limited but it's an ST-506 MFM drive. Maybe an adapter for a regular MFM drive would be possible? My paint booth is in storage because my garage has been converted into a YT studio. I'll probably build a new garage or studio someday. The first thing I'll respray is going to be my other Model 50 case
@@Epictronics1 Yeah, we probably need someone like TubeTime to reverse engineer the pinout and design an adapter. Or just design a whole replacement card that takes SD/CF cards directly, since he already has experience designing MCA cards.
@@UpLateGeek That would be great!
There's XT-IDE cards for MCA now, you should put one of those in with an IDE DiskOnModule and go to town with it as well.
Yeah, maybe, that's the way to go. Thanks for sharing
You did a much better job disassembling this PS/2 than John C. Dvorak! 😂
Haha, that was a hilarious moment in Computer Chronicles
Haha, here's the historic video with the clumsy PS/2 disassembly... 😀"Normally it pops right out!" ruclips.net/video/yoAH1aHmwR0/видео.html
I was an OS/2 developer working on an early IBM PS/2 Model 70 with a very similar case, but a 386 DX cpu.
They are very similar indeed. I have a Model 70 to restore on the channel too
That is a masterpiece of modular design
What weird power supply designs! Good to know about incompatibility between the floppy risers.
I just tested the hacked board in the other Model 50 and it works! Something is slightly different with the FDD wiring between the two boards
IBM really were ahead of their time with this design. Not just by making office PCs that are considerably smaller than the standard size (compare to the competition, who just turned the 51X0 form factor sideways), but by making it so easy to swap out parts with just plastic tabs. It's very similar to the modern mini-desktops that Dell started making about a decade ago.
Fun stuff. While the placement of those resistors suggests a high temperature is expected, it's hard to believe that 170 is normal. Unfortunately, that's all I can offer. On reflection, essentially nothing, I suppose. 😉
MCA Sound Card??
Please, take my money!
I have one of those IBMs and I dream about getting one sound card for it. It is like an unicorn.
Sound card and a proper HDD (SCSI under 2GB)!
Thanks for the great content!!
Thanks! Stay tuned, parts are on the bench already
Fortunately they're sound blaster clones back in the days was nearly imposible to find out :)
I'm surprised how often with you and other tech repair channels, how bad the job of the 'previous guy' was. Loose / missing screws, bodges, upside down chips..
Oh, I miss those old Magnesium alloy HDD brackets.
Remember them I used them at work in the computer room, I worked on IBM AS400 mainframes and NCR mainframe. But we had a number of the PC around along with some dumb terminals. Think we had a golf game on one of them when the boss was not around
Very early switching power supplies were notorious for needing a significant load in order for them to actually function correctly or even start up at all! When computers started being fitted with these new power supplies it was quite common, for example, to have high power resistors to load the power supply in machines that were not fitted with a hard drive. Machines fitted with a hard drive had a power draw that was sufficient to run the power supply without needing resistors to artificially load the power supply.
If the artificial or dummy load was inside the power supply, each machine configuration would have a different power supply to it would operate correctly. I think some machines had the load resistor external to the power supply and if the user wanted to fit the hard drive then the hard drive replaced the load resistor inside the case enabling the machine to be easily upgraded.
Ok, I should check if the temperature changes when under load, thanks
@@Epictronics1 I suppose it is possible for the power supply to be able to dynamically control a load resistor. They were usually permanently in circuit dissipating heat all the time.
I am wondering if the change in power supply was due to the industry becoming aware of the running costs of such systems, especially if all the offices in a company of education facility were to be fitted out with them. Those load resistors would rapidly bump up the total cost of ownership over time and would make such machines more expensive in the longer term.
The oil crises in the US in the 1970's created an awareness of energy consumption and started efforts to reduce it. Energy Star started in 1992. I haven't found a date for the end of production for the Model 50. I am wondering if you have an example of one of the earliest type of power supply used and an example of one of the last most advanced types of power supply used in that machine.
The grey text on the first boot was because your VGA cable wasn't connected properly. Some VGA BIOSes 'look' for a monitor, and if there isn't one it switches to a black and white output. Correcting the cable after power on won't fix it, the BIOS has decided to stay in black and white mode.
When you booted it a second time (with the new ref disk), it now displays colour because you had corrected the cable alignment.
Also, you've got me itching to repair my IBM PS/2 Model 40SX. It has some weird PSU fault whereby its over-volt detection has failed and suddenly the PSU is 'too weak' to power on anything more than the motherboard. Doesn't appear to be a fault with the floppy or hard drives, nor the ISA cards (yep, it's one of those weird ISA PS/2's!), ruled that all out easily enough. I've recapped the motherboard, although I didn't expect that to be the issue really. Just seems to be a PSU problem! Ahhh these old machines, they keep you interested in the hobby eh?
Awesome video, as always!
I didn't know that, thanks for sharing. The VGA cable is missing both thumb screws, that's why it's sketchy. The Model 40SX is awesome. Good luck with the project
When i don't have any tape i'we had sucess with aluminium foil ( the stuff you buy at the store for cooking ) to make small lil head shields :)
Yeah, I should have thought of that, thanks for sharing
I've also seen someone use strips cut from soda cans as shields.
25:35 Use an old junk HDD PCB to protect plastic parts. The junk PCB ground plane inside will suck up the heat and your plastic parts will survive. Kapton tape is ok but direct heat on it will melt whatever was under it.
That's pretty clever. I'll try that. Thanks
very nice modular system! In my computer classroom the 286 was the "teacher" computer! :) Nice camera!
Thanks Tony. I guess I'll be the teacher now : )
Oh, what a hot and fancy machine for them Micro Channel people. And a hard drive that works as a torture device.
Hot in so many ways!
I surmise someone at Framework must have had one of these machines. The various chassis pieces clipping into place for easy work is quite convenient.
My first computer was also an IBM PS2 Model 50. I have the boot up sounds tatooed in my brain. I remember playing Star Control 2 and being amazed when all the digital sound and music came out through the PC speaker, without a sound card. It brought the computer to a crawl though, but totally worth it.
I also used a DOS program that would patch the CPU to speed it up. Unfortunately, don't remember the name.
Some video controllers switch into monochrome mode if they don't detect 75 ohm termination on all 3 color pins. And you had the cable not fully inserted on that boot.
Oh, good to know. The stupid fixed cable on the 8515 doesn't have the typical thumb screws. That's why it's a bit flaky
I might have posted this in another one of your videos. But, back when I first started into computers. We would order a third party kit that included a micro channel ide card, sled, power adapter and ide cable to change it over to a IDE drive. :) Good luck finding one of those kits today. I have only seen one once in the wild at a thrift store.Stupid me didn't pick it up.
I tried to find an IDE controller years ago but gave up. I'm hoping someone will create a replica
DOH! -Missed the premiere doing my own "retro repair" on a 2010 Macbook. Great video BTW, one of these IBM machines is my dream to have in my collection
Thank! I hope you find one. It's a great machine if you're up to the MCA challenge
@@Epictronics1 Don't really know if I'm up to the challenge if I haven't tried it yet 🤣 I had one IBM from the local dumpster, i think it was a 486-100MHz. However I didn't check the motherboard closely enough and didn't realise someone removed the 3.3V CPU regulator. But the motherboard destroyed itself before the CPU was destroyed, and it was way out of my repair league, so I sold it on for cheap
Great IBM system. Steven have the same system. He have restored it. Greetings from Steven from the Netherlands
Nostalgia at its best : )
My first PC was a PS2 back in thexearly 90s. I managed to destroy the floppy drive with a badly labelled Disk. The part was IBM only and very expensive. Luckily I found a second hand one for the right price.
Lots of fun with Dos 6.x and Windows 3.x and learning Config.sys and Autoxec to get games running.
Same here, great memories from a fun time in computing
@@Epictronics1 good times.
Thank you for your great videos, I look forward to them each week, always a good watch.
@@DouglasTitchmarsh Thank you : )
This is fantastic! I’m also restoring a 50Z and 70 (simultaneously) but failing in a big way on the floppy side. I have an ALPS drive as you do, but the ribbon cable is brittle and snapped the head off when I tried to remove the connector.
Any idea where I can source a replacement? I also have two Mitsubishi drives in various state of (dis) repair.
Floppy is the last thing I need for a full restoration. Everything from the 60MB HDD to Ethernet to the memory expansion adapter are working beautifully.
Any suggestions on the floppy? I’d be happy to pay to restore it if you’re willing to try!😊
Thanks, Well, I have one failed attempt at repairing a ribbon cable. The next step is to replace the ribbon cable entirely with regular wires. I have not decided yet. I may give that a try
@@Epictronics1 these ribbon cables will be the death of me. I have a 60Mb ESDI drive that’s basically unusable because of it. The cable started to crack and at least two traces are shot. I was able to do some horrendous things to a pair of DuPont wires to get the drive to spin up but it’s not a repair. It was a one-time emergency “let’s see what data is on this drive” thing. Got it to spin up and read the platters - data is exactly as I left it in 1995 or so, but nothing of value.
Thankfully my other 60mb (and 30MB) drives work fine.
I just need a functional floppy to finish the restoration …..
@@dmurphynj I think your best bet is to find very thin wires and replace the ribbon cable completely.
1:53 Is that a 6V Panasonic CR-P2? If so it's lithium and generally lithium batteries don't leak. Inside it's really just 2x 1/2AA 3V lithium batteries connected together with spot-weld tags.
They may have used different types of batteries in these machines. I have seen some horrible battery-damaged PS/2s. They must have had some other type
My first wintel was also a ps/2 286, but a tower one. I wish I had kept that one
That must have been the Model 60. They are very nice machines. I wish I had one too :)
Happy caps as always.. I laugh everytime :)
:)
To avoid the heat damage to adjacent components, I've seen many motherboard Amiga/PC/Mac repairs on RUclips using the grab and slow twist method to remove SMD caps. I've never seen a pad pulled even when the caps were leaking.
I'm quite amazed that they never lift a pad. I'm very happy with the quick chip method, It's great
That WIMA cap needs to be replaced if you don't want fireworks going off in your PS/2! MP means metalized paper, so they are the same as the infamous RIFA firecrackers. WIMA-made ones are a bit more reliable, but they still face the same fate - just a little later.
Thanks, I'll get the WIMA out of there before I power it up again
I had a monitor where everything was yellow. I thought it was going bad.....the stupid cable was loose. It was fine. lol Well.....not that CRTs are fine, but working anyway. I've always hated CRTs.
Oh, I love these damn things :) Maybe it's mostly nostalgia, but I find vintage games look so much better on a CRT than modern displays
@@Epictronics1 CRTs are blurry and flickery. They hurt my eyes and my ears. I love the sharpness of LCDs.
Yeah, I wouldn't use that power supply with such temperatures inside. Maybe you can put a modern power supply in the metal box instead.
That is a great option. However, I'm not sure I'm going to actually use this early PS/2. Maybe, I should just preserve it as a historical piece and use a slightly newer Model 50
I looked up the WIMA MP3 capacitor and it appears to be a paper dielectric. All paper capacitors are known to eventually fail. They might not be as bad as RIFAs (which are also paper) but the time is ticking.
Ok! Thanks for sharing
A variant of the "spring retention clip" family!
That is what we will call it then
My own experience with WIMAs used to be that they never fail. Until one in a VCR I haven't used in years blew up and filled my room with the same exact noxious smell as RIFAs do. I have another identical VCR (that I also haven't used for as long) and checked its capacitors and they do appear to have developed cracks. So it might have been a bad batch. But a friend of mine says "WIMA knallt prima" (meaning they like to go bang), but in my experience, for every WIMA that blew up on me, ten RIFAs blow up (or want to because they were massively cracked)- and I think I have more electronics with WIMAs than RIFAs.
In short - look for cracks. If you don't find any, don't bother changing it.
Lol at the machine being pissed off by the Varta battery and Apple hard drive.
Thanks. That was the feedback I was hoping for. I have pretty much decided to never use that early PSU and just store it as an early PS/2 museum piece. Several viewers have left comments that it's supposed to run that crazy hot :o
The dust on HDD come from the white plastic piece at the corner
I hate those tiny flex cables. Also that power supply desperately should have had a fan back then.
The similar but slightly newer Model 70 got a fan in the power suply
The way IBM assembled thier machines was often both clever and elegant, owned several (Used) thinkpads, a PC-XT, a PC-AT (My first two PCs as a kid, hand me downs from my uncle) and an Aptiva at one time or another. However that cant be said for some of thier (especially later) desktop power supplies, though the laptop power bricks were very well built.
And dont even get me started on thier infamous "deathstar" glass plattered hard drives in the late 1990s/early 2000s.
A bit off topic but.. the thinkpads especially were rock solid, extremely well built and engineered machines.
Even used a few of them in the rain, (My customised 300e with a Pentium III 500 and Windows XP upgrade) unless you basically dropped them in a pool of water they would continue working with no issue.
Obviously DO NOT try that with a desktop PC.... lol
Totally agree with all that. I'm still using a T60 as my second laptop. Made in 2006, still works great with w10!
i think, this computers used the ESDI interface for the hard drives. Later PS/2's like the 8595 uses the SCSI interface for the hard drive and even for the CD-ROM Drive.
That is correct. My slightly newer PS/2s have factory original SCSI controllers
Another awesome video!! Great job and thanks for sharing
Thanks Rudy!
Curiosly adlib for MCA??
Stay tuned. Coming up next week
pssst... you only need a power Y (splitter) to jump from that card to the drive ;)
and of course.. a minute later =p haha
@@jakethetech4958 Yeah, I found one :)
I would replace anything resembling a rifa so yeah go ahead and replace it.
That power supply looks way too crispy to be reliable for another 20 years, I definitely second your opinion !
At the moment I'm thinking, maybe I shouldn't use this power supply ever. Just preserve it as a very early PS/2 museum piece
@@Epictronics1 If you don't need it, please do preserve it for shows only, the design wasn't replaced within a few months for no reason 😇
@@skillaxxx Absolutely. I'll keep it or put it in the hands of a collector
@@skillaxxx It would probably still run hot. Just less chance of magic smoke.
why dont you build a pico gus for the mca slot?
Is there such a project?
Which phone thermal cam are you using?
It's an infiRay P2 Pro
When I was in highschool the typing class used PS/2s and I took typing just so I could use them. The programming class was on Apple ][s and was logo. Yuck.
Replace the wima bomb
The quality of this video is kinda odd? I'm set for 1440p but it looks like 720p
Yes, sort of made my eyes go funny! 😂
I realized too late. I messed something up with the render settings
@@Epictronics1 ah well it happens. I remember back in the day the dread of realizing too late I had made the project in the wrong aspect ratio and it couldn't be changed, at least as far as I know, so I just had to crop it later and suffer with the lower overall resolution.
Ps1 is a literal love letter to pc service technicians nothing else in the time period comes close (perhapse early Macintosh?)
It is like Olivetti with all that proprietary plastic BS.
oly crap, thoes IR cameras are not cheep.
Yeah, very happy they donated it to the channel. Should be a great addition to my videos
Wima MP§: Replace it. These burn out just like RIFA (usually take longer though) and smell just as bad.
Ok, thanks!
looks like the bitrate of this video when rendering was very low. the quality of this one is pretty bad. a lot of compression artefacts.
Yes, I messed up the rendering and realized too late :/
zamzam water
*never powered on
*untested
*UHH,* how was it running at the beginning of the video?
I'm blessed with two of these weird and wonderful MCA machines
heisss
Great video
Thank you
I stop all videos, and thumbs down at the talk of complaining about [radios, computer] and other electronics that are decades old; being dirty, smelly or being in rough condition. Please think about what you are saying when writing your scripts for videos. It is quite nonsensical to mention [__] as if you expected A+. Unsubb is in order also.
Cry harder.
Sorry to see you leave, but I would have to disagree. The condition of the computers I work on varies a lot. Sometimes I find pretty much unused mint stuff and some machines are gross. I can't see anything wrong with sharing my experience with the project at hand