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Reviving a Model 80

Captain Chaos

Member
Joined
Feb 11, 2022
Messages
17
Hello everyone,

Because I needed a way to write 720K diskettes for the IBM PC XT I'm trying to repair, I decided to try and revive my old PS/2. So now I guess I'm repairing two old "PC"s...

It's a 2 MB 16 MHz 80386 Model 80 that my father originally purchased through his work for IBM. Unfortunately it no longer boots and I'm having a hard time trying to get it to.

The symptom is that after the memory test, it gives a 161 and then a 163 error code and then beeps twice. It also sometimes gives ** 301 errors, which I understand is because of stuck keyboard keys, which the keyboard now seems to be prone to, especially the space bar, but I can usually avoid those.

According to these instructions I found, these errors mean that the BIOS data is corrupt because the CMOS battery died. This makes sense. However after replacing the battery with a new one the errors don't go away (even the 161 error, which those instructions say should go away), and I also can't get it to boot from the reference diskette.

I can no longer find the original reference diskette, so I downloaded one from here and wrote it to a diskette. But the PS/2 just seems to ignore it. All it currently does is (with the reference diskette in the drive):
  1. Counts the memory
  2. The diskette drive makes the seeking sounds I remember from my youth, so it seems to work in principle
  3. Gives a 161 and 163 error and beeps twice
  4. Diskette drive light lights up momentarily, but it does not proceed
  5. I press F1, it beeps once and the diskette drive lights up momentarily again but nothing else happens
  6. I do that twice more. Now it displays the ASCII art "insert reference diskette and press F1" screen
  7. I press F1 once more. It lights up the diskette drive light one last time, and then drops to BASIC (I did not even know PS/2's still had ROM BASIC!)
Note that I took out all expansion cards and removed the power from all the hard drives and the CD-ROM. The only connected peripheral is the diskette drive.

Who can help me get this PS/2 to boot again? I no longer need it for writing diskettes, I found an old laptop for that, but this machine is nostalgic to me and I'd still like to get it to work again. Do you have any suggestions for what might be wrong? What should I check or what actions should I take to get further? Many thanks in advance for any help you can give!
 

Captain Chaos

Member
Joined
Feb 11, 2022
Messages
17
I purchased a 3½" diskette drive to use in the PC XT. Would that also work in the PS/2? What are the chances that its diskette drive is defective and is causing this problem? I can hear it both seek and spin, so it seems to work at first glance.
 

Captain Chaos

Member
Joined
Feb 11, 2022
Messages
17
I tried booting the laptop from the reference diskette I made, and that works (as far as it goes on a PC of course), so it seems to be correct.
 

mR_Slug

Veteran Member
Joined
Nov 28, 2006
Messages
874
Location
UK
Sounds like the FDD is dead. The capacitors go bad in them. I've also had alignment issues with some of the ones on the model 55sx. IIRC it's a half-height Alps drive in the model 80 with a 40pin card edge connector. Later model 80s had the PS/2 34-pin header connector. Neither connector is compatible with the standard 34-pin interface found in the PC. It's not trivial to convert a standard drive to fit. If you look around on the ardent site, there are pages about repairing the FDDs.
 

Captain Chaos

Member
Joined
Feb 11, 2022
Messages
17
Sounds like the FDD is dead.
It does still seek and spin though. Can it do that and still be dead?

I'm trying to take a look at it. If the problem is blown or shorted capacitors maybe I can fix it. Do you have tips for removing it from the chassis? It's not clear to me how it comes out and I don't want to force anything.
 

mR_Slug

Veteran Member
Joined
Nov 28, 2006
Messages
874
Location
UK
At the front bottom, of the drive, there is a gray piece of plastic, push it up, it is a clip. The drive should slide forward. If it slides forward a little bit and the gray plastic stays up, you have cleared the slot for the clip. Now the card edge connector at the rear will likely bind it up. You may have to wiggle the drive about a bit. It can be a bit stiff.
 

Captain Chaos

Member
Joined
Feb 11, 2022
Messages
17
@mR_Slug Thanks! I managed it. There's a clip at the back as well. It turns out to be an ALPS drive indeed, with an edge connector. I'm reading that those are less reliable, and also harder to repair. I understand that there are also Mitsubishi drives that are interchangeable with this and are more reliable? I guess I'll try to find one. Any tips other than eBay? I'm in the Netherlands, do you know of any European sources for these components?
 

mR_Slug

Veteran Member
Joined
Nov 28, 2006
Messages
874
Location
UK
Ah forgot about the clip. I don't know of any euro sources sorry. You may try the comp.sys.ps/2 mailing list. I think that's right. I've had terrible problems with Mitsu drives too. Got three somthing-55C drives from model 55sx's that were all bad. One fixed, only had alignment issues. Though the 40pin Mitsu may be better than the 40pin Alps, I've never owned one. You have some options:

1. You can find a tested working drive on ebay, but that may just be we send it out and hope, or it worked when removed 20 years ago. $$

2. Find someone who has fixed and or tested a drive, but wants $$. comp.sys.ps/2 should have someone who knows what they are doing.

3. Try to make an adapter. There are a few posts about 'ready-made' adapters. This usually means there are no pcb's left and you get a file you send to a pcb maker. Make sure you have the 40pin edge version. Or home brew your own, and get into the nitty gritty.

4. Fix the drive yourself. If you're good with a soldering iron, this is probably your first step. From what i recall it is the caps that go bad on those drives. There is a page or link to a page explaining what to replace.

This is the wonderful world of PS/2s. I love them but they can be a nightmare. ardernt-blue may chime-in. He knows more than I do.
 

Unknown_K

Veteran Member
Joined
Sep 11, 2003
Messages
8,507
Location
Ohio/USA
What model is the floppy drive?

I have a bunch of PS/2 systems and dead batteries plus dead floppy drives are kind of common. I repaired a few of mine and probably have a spare drive on the shelf.

You need to get a configuration disk image for your model so when you get the floppy drive fixed you can configure it. You will need a configuration file for each card installed into the machine as well.

PS/2 machines don't have a CMOS bios like pretty much every old PC has.
 

NeXT

Veteran Member
Joined
Oct 22, 2008
Messages
6,733
Location
Kamloops, BC, Canada
I've had two different Model 80's where after a recap the drives still acted like there was nothing in the drive.
The density select and media sense switches are mechanical. I found that both had switches that would always read open and couldn't see there was actually a disk in the drive until they were cleaned.
 

Captain Chaos

Member
Joined
Feb 11, 2022
Messages
17
4. Fix the drive yourself. If you're good with a soldering iron, this is probably your first step.
This is probably my first step. I can't do it myself, but I found someone who can do it (for €€€).
What model is the floppy drive?
It's an ALPS DFL713A01A. It has the 40 pin edge connector.
For the 40-pin edge-connect diskette drives, there is this pre-made converter from 'texElec
Thanks, I'll check that out!
The density select and media sense switches are mechanical. I found that both had switches that would always read open and couldn't see there was actually a disk in the drive until they were cleaned.
Thanks for the tip, that's something I can check!
 
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