The lack of solder in the through holes for osc3 is a bit sus. Wonder if there needs to be an oscillator there?

maxtherabbit wrote on 2022-09-08, 13:58:

The lack of solder in the through holes for osc3 is a bit sus. Wonder if there needs to be an oscillator there?

I found photos at France ebay lot with looks the same mobo. There is no oscillator.

It's one of pain with battery corrosion.

If the board has been turned on without having been repaired first, then it's possible that the corrosion has caused a short circuit somewhere, which is totally invisible to the naked eye.
Any component may have burned out...
And that's another pain is that in the standard AT format, the general power supply tracks are right next to the worst corroded spots.
I have already had the cases a few times where the seller had naively turned on their PC for test, and sold for part "Does not start". But fact actually grilled component(s).

Keep this card anyway if one day you have a lot of time to spend on it.

Edit: ho I remember something on one of my previous restoration - check if you have a jumper selection for RAM bank, like to select 2 banks or 4 banks are taken. And check the NPU jumper too : because maybe it was here but now no.

does the bios generate post codes? no post code at all would mean CPU doesnt even try to run bios code
would start with clocks and supply voltage to all the chips

rasz_pl wrote on 2022-09-09, 00:28:

does the bios generate post codes? no post code at all would mean CPU doesnt even try to run bios code
would start with clocks and supply voltage to all the chips

There are no post codes at all((

The battery corrosion / damage is minimal here so I doubt it´s the reason. It has also been cleaned and taken care of sufficiently.
Maybe you should desolder the keyboard connector to make sure there´s no damage underneath.

Then I would check all pins of U21 and U23 very carefully for stability of the solderings.
A single loosened pin can prevent the board from starting.

majestyk wrote on 2022-09-28, 05:57:

The battery corrosion / damage is minimal here so I doubt it´s the reason. It has also been cleaned and taken care of sufficient […]
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The battery corrosion / damage is minimal here so I doubt it´s the reason. It has also been cleaned and taken care of sufficiently.
Maybe you should desolder the keyboard connector to make sure there´s no damage underneath.

Then I would check all pins of U21 and U23 very carefully for stability of the solderings.
A single loosened pin can prevent the board from starting.

I refresh soldering for chipset. Remove old cpu and put other. Of course it gave nothing.🙁
You can see my qualification in soldering 😆

Ah - that´s why the solderings look so shiny 😉
What about U24? Does it have to be populated only when onboard RAM-chips are present at BANK0?
Have you tried non-parity or "smaller" SIMMs?

At the moment you´re using 4 sticks 1MB+parity each in BANK1= 4MB, right?