Ressurected a PS/2 Mod 70

[Big Blues]

About a month ago I picked up a PS/2 Model 70 386 for $10. I was disappointed to see that the original 386DX/16 processor had been replaced with a Cyrix 486 upgrade.

I was also disappointed (but not surprised) to see that the battery was dead, and therefore she wouldn't boot.

A couple of weeks ago I got many diagnostics disks, including the PS/2 Mod 70/80 disk. I finally got around to trying it out. Fired it up, booted the diagnostics (with some nasty sounding floppy sounds), and it looked well. Then it started griping about the floppy disk. Then it quit booting from the floppy. Things weren't looking good. I had heard about these Alps drives.

Not being one to give up, I inspected the outside of the drive - looking for any reason why it would give up with time. I noticed that there's a belt with a piece of metal going around the bottom spindle, with a sensor that obviously watches this metal. Noting that the metal looked kind of oxidized, I scraped it with my fingernail a bit. Threw the drive back in the computer, and there we go, one working Alps drive (booted clean, no nasty sounds and quick loading), and one booting 70.

Nothing exciting on the hard drive after all that though.

Joel

 

[chuckcmagee]

I had to put a refurb hard drive in my P70. The existing HD387 just would not spin anymore. I read on the internet that someone had good luck putting a 16MB ram chip in the P70 and running it with 24MB. I have some 16MB on the way to see if it really works. It has 2 x 2MB in it now. The 16MB were cheap enough so if it doesn't work, I won't be crying.

 

[IBMMuseum]

P70 SIMM upgrading

P70 SIMM upgrading

I read on the internet that someone had good luck putting a 16MB ram chip in the P70 and running it with 24MB. I have some 16MB on the way to see if it really works. It has 2 x 2MB in it now. The 16MB were cheap enough so if it doesn't work, I won't be crying.

If it does work be sure to reveal it to those that have studied upgrading the P70 specifically: http://incolor.inetnebr.com/jshorney/p70.htm#p70up

Did your source talk about changes to the "Presence Select" traces on the SIMMs? The only thing I think if unmodified is that they match an actual PD bit setting, but the system sees it as 16Mb (and needing a parity bit to run in a P70). Were the 16Mb SIMM truly recognized it means that all of the four slots could be filled with a 16Mb SIMM (the P70´s big brother, the P75, likes only 4Mb modules in the four planar SIMM slots).

 

[chuckcmagee]

"Gee Chuck, it would help if you read the entire description in the article" Snicker, guess it's off to ebay to see if I can find a MCA McMaster board. I skimmed over that part. Likely going to put OS/2 on it anyway so faster processor will be good.