Thermalwrong wrote:

I just got hold of a pile of old motherboards, with this being the most interesting one. It's a 486 non-AT/ATX format board

This is the LPX standard, used a lot for OEM systems in the early to mid 1990s.

with a 486 socket and what looks like a CPU with that heatsink glued onto it.

Ooh, something like that in an IBM sounds like a Blue Lightning 😀

[...]

It looks just like the motherboard in this thread: IBM PS/1000 486DLC2-66

It has the same integrated CPU, but the CPU casing is regular plastic instead of silver. This board has a WD90C33 card instead and of course there is no cache.

I'd say it's the same, probably made by Alaris for IBM.

I've been looking around for specs of a machine of this type, which Might be the IBM PS/1000, but I can't find anything that's a desktop type board:

The board is exactly the same, it's just the riser that's different. I'd say this looks like a late PS/1 or an early PC330, but I'm not too hot on this period in IBM's history.

Try googling the IBM FRU numbers on the board, that usually shows up quite a few hits.

I haven't plugged it into anything yet, I think it needs a clean first - what's the best way to do that? just check that components are secure and then give it a wash in the sink, or do it more carefully with IPA?

Blow off the dust and check for bad components (exploded caps, leaking battery). If you see that sort of stuff, that needs fixing first. If not, just fire it up. Making everything spic and span is nice for display but pretty irrelevant for functionality.

Something tells me that this is not an IBM board. Though it looks high quality, it just dont look IBM'ish.
Never seen that video connector for a daughterboard on any IBM from that era.

dionb wrote:

Ooh, something like that in an IBM sounds like a Blue Lightning :) […]
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with a 486 socket and what looks like a CPU with that heatsink glued onto it.

Ooh, something like that in an IBM sounds like a Blue Lightning 😀

I'd say it's the same, probably made by Alaris for IBM.

I've been looking around for specs of a machine of this type, which Might be the IBM PS/1000, but I can't find anything that's a desktop type board:

The board is exactly the same, it's just the riser that's different. I'd say this looks like a late PS/1 or an early PC330, but I'm not too hot on this period in IBM's history.

Try googling the IBM FRU numbers on the board, that usually shows up quite a few hits.

I haven't plugged it into anything yet, I think it needs a clean first - what's the best way to do that? just check that components are secure and then give it a wash in the sink, or do it more carefully with IPA?

Blow off the dust and check for bad components (exploded caps, leaking battery). If you see that sort of stuff, that needs fixing first. If not, just fire it up. Making everything spic and span is nice for display but pretty irrelevant for functionality.

Thank you for the pointers, I'll give the board a go, so far I've only found one capacitor that's knocked off but it's covered in dust and pet hairs.

I didn't have any luck looking up the part codes on the board, but in picture 3 you can see that the video board has "486 IBM BL" on there, which was the best clue so far. The only IBM style part code I've found so far is on the riser board.

I have a PS/Value that looks quite similar to this, only it uses a proprietary COAST module for cache ...

yep looks very similar to my PS/Valuepoint also, but never seen one with a video daugherboard like that... they had a ton of different motherboards that went into those so it's certainly possible

compaq also had similar form-factor motherboards to that, but they would usually have some wacky logo or image silk-screened somewhere on the board