Acer V58 Vintage Socket 7 Motherboard

[tony359]

Hi all,

I'm trying to troubleshoot a vintage Acer V58 motherboard, ALI chipset 1541/1543. Symptoms are: it's very dead.

The CPU in question, a plain Pentium 200, it works on a different board. I have checked the voltages, the clock and the reset lines. All checks out.
However I have ZERO activity on the CPU data/address lines. It's like the CPU is told NOT to start but I cannot figure out how. A post-card shows "--" and there is of course no activity on the BIOS address/data lines.

I checked the HLDA (Hold Acknowledge) line which could indicate the CPU is told to wait - but no.

Does anybody have any pointers for me to check?

Thank you!

[stj]

check all the voltage regulators, maybe a buffer or the ram has lost power

[tony359]

Thanks.

The CPU should do something without RAM but there is zero activity. No post codes, no beeps, no activity whatsoever on address/data lines. It's like the CPU is in reset mode.

There is really not much on that board. I haven't checked the 3.3V at the RAM to be fair but I am testing without RAM for the time being. I can definitely check that all the other ICs on the board are powered - but I would still expect to see some pulses coming from the CPU when the RESET line is disabled, would you agree?

[stj]

x86 is niot as simple as 8bit stuff, the cpu wont touch the bus unless it gets some signals from the chipset telling it the bus is available and not in use by something else.
i would still begin by checking all the 3pin regulators you can find - because it's easy.

got any pictures?
btw, if it has cache chips - are they getting hot?

btw - found this: https://theretroweb.com/motherboards/s/acer-v58

[stj]

this board is strange, if the jumper pdf is corrct you have to tell it how much ram is installed!

[tony359]

Yes that's the board and those are my pictures

Nothing is getting hot. I'll check regulators again but there is not much on the board. The only regulators are for RAM, VCORE and IO. IO and VCore are ok. I can check the Ram one but I'm not testing with RAM for now (yes, I also have tested with it).

Where do you see the RAM size thing? I don't see it on the jumper sheet/manual.

Yes, I appreciate Socket 7 is a bit more complex, but that's why I've posted here I think I've depleted the "basic" options (reset line, voltages, clock) and I'd like to know what could hold the CPU in that state. I've studied the P54C white paper and checked those pins which would obviously stop a CPU (HOLD etc) but I haven't found anything so far.

[tony359]

I had forgotten I had a thread here on BadCaps about the Infamous V58!

I've managed to fix this board - well fix... It's not really a fix!

Made my usual videos 😊

Part 1:

Part 2: