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IBM PS/1 problem

I

im_an_alien

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Joined
May 10, 2007
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121
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Waleska, GA
My PS/1 won't boot. I can't figure out what's wrong with it. I turn it on, the HDD and PSU fan start spinning, but that's it. No video, no beeps. It won't even try to boot from a floppy, even when I disconnect the HDD. Another weird thing is that my printer goes offline when I turn on the computer, and won't go online again until I turn the computer off or unplug the printer. Any idea what's wrong with it?
 
Shot in the dark, but it kinda sounds like a power fault of some kind. Assuming the printer is powered by its own outlet and not the computer, is something inside the case grounding out the motherboard or power supply? Did you try to reseat chips in case something got loose or corrosion/dust? If these are on a power strip, did you try another power strip?
 
Vlad said:
Shot in the dark, but it kinda sounds like a power fault of some kind. Assuming the printer is powered by its own outlet and not the computer, is something inside the case grounding out the motherboard or power supply? Did you try to reseat chips in case something got loose or corrosion/dust? If these are on a power strip, did you try another power strip?
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Printer is powered by its own outlet. Haven't tried any of those fixes (it is on a power strip), but I will later. As far as corrosion/dust, there's a TON of dust in the case, so I'll try that.
 
Meh, still can't get it to work. I pretty much took the entire computer apart, blowing off dust wherever I found it (and also where I didn't, as was the case for the CPU and BIOS chips). I also plugged it directly into the wall.
 
Tried that, didn't work. However, by taking out 2 sticks I got it to give me a gray screen with "000000 0001 201" (IIRC) on it, so I'll keep messing with the RAM.
 
Ok, well, if you're using 30 pin SIMMs, it's telling you some are missing.

In that case, take the two in there out, put the other 2 back in, put the two that were in there originally in the two empty sockets and try booting.

The idea here is that, if the fault is in low RAM, you want to move those higher up in the stack so that it MAY boot and give you an error during the memory count. That way, you will know that the bad strip is in SIMM 3 or SIMM 4 and can replace them one at a time until it works.
 
Sorry about the MASSIVE bump, but I'm coming back to this computer after a year and a half of it sitting around half-assembled.

Some time between the last time I touched this computer and now, I got a PS/2. The PS/2 won't boot for an entirely different reason (apparently the battery's dead), but it does get through RAM check fine. So I took the RAM from the PS/2 and put it i the PS/1, and it still doesn't boot. So is it a problem with the motherboard, and if so, is there anything left for me to do other than scavenge what I can and trash the computer?
 
I had a similar problem with my PS/2 30-286. In the end, I had to abandon the motherboard. It was dead somewhere, and I just couldn't get to the bottom of it (one of the boards in this story). Once things go on these surface mount VLSI motherboards it can be a hard task tracking the issue down.

Tez
 
im_an_alien said:
So I took the RAM from the PS/2 and put it i the PS/1, and it still doesn't boot. So is it a problem with the motherboard, and if so, is there anything left for me to do other than scavenge what I can and trash the computer?
Click to expand...
Moving RAM from a particular PS/2 model to a PS/1 may not be a valid thing to do. Were the sticks from the PS/2 the same part number as the ones in the PS/1 ?
 
Model/submodel coding is helpful for both PS/1 and PS/2s, because RAM can vary (on at least PS/2 models) from proprietary 30-pin SIMMs, 72-pin SIMMs, or proprietary modules that no other systems have. A few of the PS/2 models also want memory added in particular banks before others. With the model identification, it is better possible to be able to help by at least knowing what you have.
 
im_an_alien said:
The PS/1 is a 2155 and the PS/2 is an 8550/50Z
Click to expand...

So putting a single 1 or 2Mb 72-pin SIMM that is 85nS, designed for a zero wait state 286 10MHz system, into a 486-class PS/1, CPU running at least at 25MHz?...
 
PS/2 72-pin SIMMs in particular had "Presense Detect" ("PD") wiring link encodings in one corner of the SIMM. Four solderpad connections were bridged or unbridged depending on the capability of the module. In some very rare instances, the encoding could be changed to adapt it to another system (the one I am most familiar with changes a 16Mb ECC module typically from an IBM Server 320/520 to behave as an 8Mb parity module for an L40SX PS/2 laptop).

For that difference in system requirements that can't be changed in your instance of having an 8550 and trying to put the module into a 486-class PS/1...

Your PS/1 probably needs the very common 8Mb 70nS modules with parity that should be easy enough to find...
 
So putting a single 1 or 2Mb 72-pin SIMM that is 85nS, designed for a zero wait state 286 10MHz system, into a 486-class PS/1, CPU running at least at 25MHz?...
Click to expand...
Yeah, I guess so, except that they're both 30-pin. I guess I should mention that the RAM I pulled from the PS/2 was on some sort of a RAM extension card. Though I would expect that it would at least give me a different error for "wrong kind of ram" than "dead ram" or "missing ram"

Also, the ram from the PS/1 is 1MB and 80ns.
 
im_an_alien said:
Yeah, I guess so, except that they're both 30-pin. I guess I should mention that the RAM I pulled from the PS/2 was on some sort of a RAM extension card. Though I would expect that it would at least give me a different error for "wrong kind of ram" than "dead ram" or "missing ram"

Also, the ram from the PS/1 is 1MB and 80ns.
Click to expand...

30-pin SIMMs for 16-bit microchannel cards are typically low-capacity (256Kb), and may have a proprietary pinout that is changed from standard 30-pin SIMMs...

It´s going to be as slow (85nS) or slower than the planar RAM too...

I think there would still be too much difference between the models...
 
Your 2155 is pretty much a standard PC, nothing special about it. If there's no memory installed, you should get POST beeps. Try this trick, it works with all PS/1 models.

With the computer off, press and hold down both mouse buttons, then turn the computer on. Keep the buttons held down until the computer beeps, then let em go. This forces a reconfig.

Yes, PS/2 memory wont work in any PS/1 model except maybe for the 2123.
 
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