IBM PS/2 Model 50 (8550) - Stuck on Error 167
Posted by Corrupted_00@reddit | vintagecomputing | View on Reddit | 43 comments
I'm working on restoring an IBM PS/2 Model 50. This is the first time I've worked on such a machine, So I am figuring things out as I go. On startup, the system beeps twice and usually shows error codes 161 and 163, though sometimes I see 162 and 163 or just 164. After pressing F1 as prompted, I always get error 167, at which point I can’t proceed any further. I though the problem might be a result of the old CMOS battery being dead, but changing it made no difference. I tested both the battery and the contacts that connect it to the motherboard, and everything seems to be working perfectly.
As seen in the first photo, I do have an McIDE-CF adapter and a generic 3.5 inch floppy drive that's being adapted to work with the system. I've tired booting the system with different parts disconnected to see it any of them were the problem, but to no avail. The floppy drive itself appears to spin and the light on the front does work, but I can't get the Reference Diskette to load. I don't really have any other clue as to what could be causing the problem, so for now I am stuck.
Any advice would be greatly appreciated.
Zdrobot@reddit
I just love the way PS/2 machines look, always had.
The monitor, the box itself, and the Model M keyboard, of course.
IBM PS/2 is firmly in my top ten list of retro machines. One day I'll get one, though not today.
But today I'm going to go get a 486 ValuePoint :)
Corrupted_00@reddit (OP)
It is quite a cool system all around. I found mine sitting outside a surplus store, and the owner said I could have it for $5. From what i could see there and then, the case was covered in rust from being left outside for so long. Upon testing it, I very quickly discovered that out of everything the computer had inside of it, only the motherboard, speaker, and fan worked.
The power supply apparently had a varistor catch on fire, but that's by far not the only problem with it. I still plan to diagnose and fix it up sometime, but I don't have enough time at the moment.
The hard drive decided to kill itself the moment it spun up, like I mentioned to another comment under this post. So, no cool PS/2 HDD noises for me, I suppose.
I ordered a proper floppy drive that would have worked with my system without an adapter and was sent the wrong thing. Thus, I opted to just use a generic floppy drive I had lying around and an adapter, but even that doesn't work as mentioned by another comment.
The keyboard was what annoyed me the most, I started out with an IBM 3151 Terminal Model M, which wouldn't really work. Later on, I found a proper PS/2 model M, but that one didn't work. The contact pads had deteriorated almost beyond recognition when I opened it up. The Model M I have now is a Frankenstein's monster made up of the bottom cover and bulking spring mechanism of the Terminal Model M and the board, speaker, lights, and top cover from the PS/2 Model M.
Lastly is the monitor, which I'd love to have, but I'm not too keen on getting one online. Prices are rather high, and I've heard horror stories of shipping CRTs gone wrong, so for now, the generic VGA monitor I'm using will have to suffice.
Safe to say, it's been one hell of a journey working with it.
Zdrobot@reddit
Whoa, that's quite a horror story!
I'd buy a PS/2 if even to marvel at it's case though. Hope one pops up eventually in my country (I live in a small country, so..)
Corrupted_00@reddit (OP)
I hope I didn't come off as discouraging.The one I came across just happened to have a lot of issues. Although somewhat frustrating at times, I've had an amazing time working on it.
Hopefully, you, too, come across one someday. It really is quite an interesting machine to mess around with.
IncreaseLegitimate16@reddit
Did you look up those error codes?
Corrupted_00@reddit (OP)
Absolutely. From what I've read, 161 and 163 relate to setting the date and time, 162 and 164 relate to running the setup procedure. Meanwhile, 167 indicates that the system clock is not updating, which is why I replaced the CMOS battery. Since I can't get past 167, I can't run the setup procedure, hence all the other error codes.
IncreaseLegitimate16@reddit
That is a rather frustrating problem. Chances are your RTC chip or your crystal have gone south. Which, given the age of the machine, I have seen happen before. Can be a real pain to figure out though.
Corrupted_00@reddit (OP)
Yeah, I was hoping it wouldn't come to this, but I guess I dont really have any other option. I'll find new EPROM chips and flash them with the BIOS image. If that doesn't solve the problem, then I'll also replace the crystal, and hopefully, that puts an end to this whole ordeal.
pmodizzle@reddit
Are you sure the floppy drive is working? Tested in other machines?
Corrupted_00@reddit (OP)
Unfortunately, I do not have another machine that uses these types of diskette drives on hand. I did test another diskette drive, but that didn't change anything. Like I also mentioned in the post, the light on the front of the drive does turn on, and the motor does spin up when the computer is turned on. As for the floppies themselves, they all work with my laptop, and I've tested multiple with the PS/2, so I doubt they are the issue.
pmodizzle@reddit
Is the floppy drive light persistently on or does it just come on and turn off?
Does the drive continuously spin or just initially and then stop?
You say a regular fd was adapted to work, can you provide more specifics/pictures?
It shouldn’t be a matter of changing the battery at this point, once you are able to boot the reference desk, then that should help to take care of the error codes that are coming up. Even if you did not have a battery installed at all, you should still be able to boot off a floppy disc either to the reference desk, or even just straight to DOS. This is why my questions are focusing more on the floppy drive itself, because that seems to be the root of the problems.
Corrupted_00@reddit (OP)
The diskette drive itself is a Sony MPF 920 that I just had laying around. The light on the diskette drive turns on the moment I flip the switch and turn the computer on, and it stays on the entire time. The motor spins for a bit as the computer starts up and then stops. Putting in a diskette does nothing.
The other diskette drive I tried was a proper IBM PS/2 drive (unfortunately I dont remember the model number), but it used the same interface that the drive I have now does, meaning I still had to use the adapter. When starting up the system, both the light and the motor would work the entire time regardless if I had a diskette in or not.
pmodizzle@reddit
This sounds like a drive connection problem - when the motor continuously spins and the light is continuously on that means voltage or signals are probably going somewhere it shouldn’t. Can you share pics of what your floppy drive connection cables are looking like?
It really sounds like something is misconnected or miswired.
Corrupted_00@reddit (OP)
Here is the entire setup.
pmodizzle@reddit
Is your floppy drive cable plugged into the floppy drive the correct orientation? The red stripe should align with Pin 1 on the connector (should be marked on the underside of the motherboard)
Corrupted_00@reddit (OP)
Small update! I replaced the floppy drive with a completely different one, a Panasonic JU-256A216P. I plugged everything in, but it made no difference. This floppy drive doesn't have a plastic enclosure around the 34-pin connector and thus has enough space to allow me to plug in the connector upside down. I decided to do just that, and it actually ended up working! It appears that whoever made the adapter soldered the cable backwards.
Unfortunately, while the floppy drive does work as it should now, I am still stuck behind error 167. Having the diskette in from the start or inserting it later makes no difference.
pmodizzle@reddit
Ok so progress!
So when you say it works do you mean you’re able to use a dos boot disk to boot?
If that is the case, then it should be able to boot the reference diskette. What program are you using to write the image file to the floppy disk? Do you have another floppy you can try in case the original one is bad?
Corrupted_00@reddit (OP)
No, by works, I am referring to the fact that it goes through the checking procedure like the PC Convertible floppy did. However, I still can't boot the reference diskette. I'm using WinImage to write the images, and I've used multiple floppy diskettes, some of which I used when I installed Windows 95 on my HP Internet Advisor, so I know for sure they work. I've also tried the 720 kb DOS 5.0 floppie I use on my PC convertible, but to no avail.
At this point, I'm starting to think that the system clock is just completely dead.
pmodizzle@reddit
Any corrosion on the battery terminals or any way it wouldn’t make good contact?
Corrupted_00@reddit (OP)
Nothing of the sort. As I mentioned in my post, I already tested the battery itself and all the contacts down to where it connects on the motherboard.
Right now, my plan is to just go the nuclear option, get 4 27256 EPROM chips, flash them with the proper BIOS, and completely replace the ones on the motherboard. I managed to get my hands on a BP-1200 Universal Device Programmer for this express purpose. Granted, I've never done this before, but it wouldn't hurt to try.
pmodizzle@reddit
For your sake hopefully that does it. Seems that rtc chip in a 28pin package isn’t too easy to come across.
Corrupted_00@reddit (OP)
Yup, it is indeed in the correct orientation. Since it is keyed, there is no wrong way to plug it in.
I'll see if I can get my hands on another floppy drive tomorrow. Unfortunately, it'll probably just be another generic one, but hopefully, that makes a difference.
invokes@reddit
Check Ardent tool website. You're running the ref disk?
Corrupted_00@reddit (OP)
Yup, that is the website I've been using for the technical manual as well as the reference diskette images. I have the reference diskette in the floppy drive, but all that appears on screen is error 167.
invokes@reddit
The original floppy drive didn't work?
If the floppy drive is seeking but isn't reading the ref disk it might be that the ref disk is missing the magic byte.
Also worth noting, the IBM PS/2 Facebook group is also worth checking out.
Corrupted_00@reddit (OP)
No, unfortunately, it didn't have the original at all. The only thing that was present when I got it was the motherboard, power supply (which was dead, the power supply it has now is one from a Model 55, hence the red switch instead of a white one), speaker, fan and hard drive.
Just to put the state of the computer when I got it. In the first photo, you might notice that the hard drive is not plugged into its respective card. This is because upon receiving the card and plugging everything in, the hard drive decided to undergo a partial unscheduled disassembly process, snapping two of the arm heads inside and rendering it completely dead.
invokes@reddit
Ooofff. That's definitely a starter for 10! Yikes! In theory you should be able to use another floppy, but might need to check wiring. Post to the FB group and someone there will know. Will post links tomorrow as just turning off.
Mike1978uk@reddit
Looking at ardent it’s 1.44mb disk image. Perhaps try writing the disk again I’ve had a batch of disks be a bit tricky with images at times and maybe try a few drives. Some usb drives don’t like those images. If winimage can write the disk and verify it then it might be good. Also you can try running the refstamp utility on the disk also on ardent. https://www.ardent-tool.com/utils/refstamp.html & https://www.ardent-tool.com/disks/ The errors you are saying are that the date time isn’t set and you need a ref disk to set the time. So if the ref disk boots then you have to manually set the time on the set configuration option.
I can’t recall also if the model 50 uses the Dallas chip or the larger battery. I read you changed this. The one time also i had issues was changing the Dallas battery and it wouldn’t boot and had to reset the CMOS it using some debug commands. So you could also try this that was a model 55sx.
Debug:
o 70 13 o 71 00 q
https://www.ardent-tool.com/8555/Planar.html see clear cmos on this link. (As above)
Corrupted_00@reddit (OP)
Well, I fixed the issue I was having with the floppy drive, but that doesn't appear to make any difference.
The battery is a CR-P2 6V camera battery. You can actually see it in the bottom left corner of the first photo. I already tested it to see if it's good or not, and it does indeed output 6V.
Regarding BASIC, the computer doesn't let me type out anything. In fact, it starts beeping if press anything on the keyboard enough times. I can do key combos, Ctrl+Alt+Delete works, for all that's worth. I'm not aware of any other way to access BASIC.
Mike1978uk@reddit
Feels there something else going on at the very least if things aren’t working you would expect to drop to get to basic even if the ref disk won’t boot.
Corrupted_00@reddit (OP)
All I get is the screen that prompts me to press F1 and then the error 167 screen shown in the third photo. I've let the system run for a while just to see if it would do anything, but even after 20 minutes or so, nothing changes.
Mike1978uk@reddit
The jp1 on the fdd interface have you tried breaking the connection. You can break this by scratching between the two pads. I can’t recall if I did this or not on a model 30. If you aren’t able to boot an fdd then it’s worth a try. You can reconnect with a graphite pencil if you do so or a blob or solder.
Mike1978uk@reddit
167 is a bios issue. You could also try removing g the bios chip and cleaning the contacts using a pencil rubber. In fact any socketed chip that can be removed and replaced is worth a try in this situation.
Corrupted_00@reddit (OP)
That doesn't appear to make any difference. My best guess at this point is that something is just completely dead. Is it possible to find replacement chips?
Mike1978uk@reddit
If the chips have been backed up then you could try rewriting the bios chips from those I linked
Corrupted_00@reddit (OP)
Yeah, I saw that, but I can't get to the DEBUG menu, so I'm not able to do anything at all.
Mike1978uk@reddit
Failing this go ask on the fb group for microchannel servers there’s a few people there ie IBM Museum (aka David) who might be better suited to advise further
Mike1978uk@reddit
The other side of things to check would be the bios chips: https://www.ardent-tool.com/firmware/system.html
Buzz729@reddit
PS/2 was a great idea, but overpricing them was stupid.
Corrupted_00@reddit (OP)
Personally, I love IBM machines, no matter how weird some of them may be. The biggest downside to the PS/2 lineup, in my opinion, is the proprietary MCA architecture. Even dealing with it now is annoying, so I'm guessing it would have been way worse when these things were new. Then again, I'd be lying if I said I didn't enjoy tinkering and learning more about it.
Buzz729@reddit
MCA was a good idea, but IBM charged through the nose for it. They also stuck with Intel processors despite the PS/2 coming out at a time when Intel could not keep up with AMD. The slowest AMD 386 was considerably faster than those from Intel.
Never stop learning and tinkering! My weakness is vintage gear. I love getting pieces in that don't work and debugging. The only two that are peripherally related to computing are the Lavoie LA-239 and Heathkit IO-10.
The '239 was used for testing on Nike missiles, and there were data lines going from missile sites to AN/FSQ-7 computers. These were building size behemoths. When they were shut down, Hollywood bought pieces to use as props. You can see some pieces in the 1960s shows like Batman, Voyage to the Bottom of the Sea, and The Time Tunnel. A friend gave me two '239 carcasses in rough shape with a challenge to put together a working scope. That was fun, and it works.
The IO-10 was a kit sold in the early 1960s with one use being as a "computer monitor." This must have been for logic tracing or as an analog output. A guy at a hamfest saw me looking at it and offered to trade it for my coffee mug. The mug was too special, so I passed. He said, "take it anyway. It only needs a diode." Ha! It needed far more than a diode, of course.
Corrupted_00@reddit (OP)
So far, I've only really played around with vintage computers and not testing equipment. I do plan to tinker around with some vacuum tubes as well, and I managed to find a Precision Tubemaster 10-12 in what i can only describe as a horrific state. I have since repaired it, replaced a big chunk of the deteriorated wiring and resoldered a bunch of loose cables, but the biggest challenge thus far has been cleaning it. It's getting there though. In the future, I have my eye on a few scopes, and most notably, an HP 16702A Logic Analasys System.
pmodizzle@reddit
You need a reference disk - it is the equivalent of having a bios to change settings with. This requires you having a working floppy drive which is far from certain on these PS/2s.
https://www.ardent-tool.com/disks/ - image files here. That site is also a huge reference for PS/2s.