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itsvince725

Vince's Conquests

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On 2/10/2018 at 12:28 PM, itsvince725 said:

It has a 386DX-20 and 6MB of RAM installed, which is certainly better than if I had picked a 16MHz machine with 1MB.

Hey, that's a perfectly swell Model 70. They can't all be 70-A21s with the i486 Power Platform upgrade. (Upgrade alone was $3,995 in late 1989, and the A70 to stick it in was nine grand. I'd totally love to get my paws on one of those. Or maybe a model P-70 or P-75 with the red plasma display.)

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I dug through an entire stack of the things trying to find a DX-25 but they were all DX-16 or DX-20.

 

...well, except for one that seems to have a silver metal cap with a IBM part number glued over the CPU. I have no idea what was going on with that one, it was the only one that didn't have a normal 386.

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My only problem right now is that I get error codes after the memory count and have no idea what they mean. Haven't found a resource yet...but I can guess at least one is CMOS related.

 

eQtB9PS.jpg

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Was about to post the same link. So, yeah, it doesn't look like there's anything too serious but you'll have to boot the reference disk. The need for that is one of the bummers related to PS/2s. (Where it really turns ugly is if you end up in the state where you need to boot the reference disk but your floppy drive is kaput...)

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Making a reference disk is no big deal but replacing the CMOS chip might be...I'm hoping it's a DS1287 because then I can buy a replacement off eBay with a coin cell holder.

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39 minutes ago, itsvince725 said:

...well, except for one that seems to have a silver metal cap with a IBM part number glued over the CPU. I have no idea what was going on with that one, it was the only one that didn't have a normal 386.

What was the model number? There's no chance it might have been something like a Cx486 upgrade chip, is there? I think IBM may have produced those with their own house brand on them. (Not to be confused with IBM's own "Blue Lightning" chips, which were conceptually similar but never came in a PGA format; Blue Lightning-based 386 upgrades came in the form of little boards with a QFP soldered to them.)

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1 minute ago, itsvince725 said:

Making a reference disk is no big deal but replacing the CMOS chip might be...I'm hoping it's a DS1287 because then I can buy a replacement off eBay with a coin cell holder.

 

According to the pictures here the Model 70 has an external battery pack mounted near the speaker? I know some other PS/2 models use Dallas chips with the integrated battery but I'm not sure the Model 70 does.

http://www.classic-computers.org.nz/blog/2009-09-27-restoring-a-ps2-70.htm

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You're right, that probably is the battery. Guess it's time to go to Batteries and Bulbs or whatever and see if they have a replacement.

 

I really hope this floppy drive works, because otherwise I'm kinda screwed.

 

Also, I noticed mine has a different board design than in that link, despite them both being 20MHz models...

 

oB1o9UN.jpg

Edited by itsvince725

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Here's a page that notes that oddity of some of the 20mhz models using the larger planar. Doesn't have any explanation for it, though.

 

http://john.ccac.rwth-aachen.de:8000/alf/ps2_70121/

 

The page also talks about the metal-cased 386 chips. Apparently it's a regular 386 manufactured by IBM under their internal-use-only cross-license; IBM didn't do ceramic packages like Intel so they used the same cans as the MCA chipset components...

Which is actually sort of cool. You might want to snag that metal can chip, it could be a collector's item someday. ;)

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Wow, how interesting! I wonder if the smaller planar was a later revision, since my machine has what I assume is a BIOS chip with a 1989 copyright date on it.

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40 minutes ago, itsvince725 said:

Sure did! I dug through stacks of them until I found one I was satisfied with...

 

That one is clean.  I saw all those when I was there and I was wondering how many Model 70's were in that stack...

 

What version of OS/2 are you planning to run on it?

Edited by rickrob

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36 minutes ago, luckybob said:

I'm curious, whats this kemner?  

 

It's a surplus warehouse in Pottstown, PA.  They have a bunch of old/vintage machines there.

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13 minutes ago, rickrob said:

 

That one is clean.  I saw all those when I was there and I was wondering how many Model 70's were in that stack...

 

What version of OS/2 are you planning to run on it?

Probably 2.1 or 2.11. Anything newer might have issues on a 386.

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I doubt you'd *technically* have a problem with any version of OS/2 on a 386. (Or at least any IBM released version, your mileage may vary if you start talking about eComstation and all its pre-installed add-ons.) I suspect the biggest limiter is going to to be RAM. 6MB is going to be pretty tight even for 2.x. (I ran it briefly in 4MB, and that wasn't pretty. 8MB was... okay. Just okay.)

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Oh, I plan to upgrade the RAM to 16MB anyway. 6MB is only good enough for DOS and Windows 3.1.

 

Just will need to find some 8MB parity SIMMs, since there's no other way to get 16MB with 3 RAM slots.

Edited by itsvince725

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I'm pretty sure that 2mb is the biggest SIMM those boards accept, IE, if you want more than six megs of RAM you'll need to add a memory card. (Silly, I know.)

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Well, you CAN install a memory expansion board.  This memory isn't as quick as mainboard memory, but its a far sight better than hard drive cacheing or having programs NOT run at all.

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8 hours ago, Gorgonops said:

I'm pretty sure that 2mb is the biggest SIMM those boards accept, IE, if you want more than six megs of RAM you'll need to add a memory card. (Silly, I know.)

Seriously? That's lame as hell. God I hate old RAM limitations.

 

That's another card I gotta track down...

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