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I found an Asus SP97V Pentium-I motherboard. It works with both AT and ATX power supplies. At least it's supposed to, because it actually doesn't.

I put a Pentium 120 CPU, four RAM modules and a Cirrus Logic PCI VGA into it to test. All of these work in a different mainboard. The power supply also works.

This board seems to be faulty. It doesn't boot, nothing appears on the VGA. The power LED doesn't turn on, and the connected PC speaker doesn't make any noise either.

Yet the CPU is getting warm, the CPU fan spins, and I can measure correct voltage anywhere I try.

What do you think might be wrong with this board? I'm fairly sure I set the jumpers correctly. Even if I didn't, the power LED is still supposed to light up, doesn't it?

I know, normally one should just throw away a faulty motherboard, but I'd hate to trash such a high quality vintage board if there's some hope to fix it.

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  • my bet is faulty chipset ... They started to use BGA for those around Pentiums and the BGA technology is not reliable even today ... so the chipsets where corroding from inside ... sometimes reball-ing helps but for those old chips usually too much heat damage makes permanent inside chip damage ... Sometimes heating the chip with hot air helps to kick start it for a while (cheap trick in HW service) but with decreasing its life span considerably ... towards digital death. To rule out peripherial fault/incompatibility remove all of it RAM,gfx ,... leave just the speaker+CPU if it beeps or not.
    – Spektre
    Jun 13, 2021 at 8:34
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    Double check your jumpers with regards to the CMOS. Many motherboards have a jumper that must be closed/open to blank the CMOS. Some of them warn you about attempting to power on in a certain state, other boards require you to power on momentarily, then unplug and toggle the jumper. I have many boards that will 'act bricked' if powered in a CMOS reset configuration inadvertently, and then act normal when the jumper is reset. Make sure that jumper is in the safe, correct position for booting. Clearing the CMOS is a good idea in this case before slowly testing with new cards/rams one at a time.
    – knol
    Jun 13, 2021 at 17:37
  • No, there's no beeping with or without CPU/RAM. I cleared the CMOS, and checked the clear jumper, it's not the source of the problem. Meanwhile I connected an ATX PSU and found that the ATX power switch still works. For the time being I'll retire this board, then test it when I my PCI diagnostics card arrives. Apparently it can be dead for a gazillion reasons. Thanks guys!
    – Tamás Polgár
    Jun 13, 2021 at 22:51
  • On old boards you need CPU for beeping ... so If you did try with just CPU , no RAM modules or CARDS (just CACHE ICs) then its 99% chipset ... and 1% something else like bad CACHE,CPU or other circuit fault,... faulty PSU usually starts but makes computer unstable so I doubt its that ... also old motherboards needs to have CPU jumpers configured correctly for used CPU ... like FSB and Multiplier. Check this stason.org/TULARC/pc/motherboards/A/… so check FSB,multiplier and Voltage for Intel in case there where different CPU before
    – Spektre
    Jun 14, 2021 at 7:15
  • I highly recommend one of those $7 no-effort ATX PSU testers where you plug the PSU into it, turn it on, and it displays a bunch of metrics (eg. voltage on each rail, etc.) with any out-of-spec ones beeping and flashing. First thing I bring out whenever a PC isn't behaving perfectly. (If it boots, memtest86 is the second one.)
    – ssokolow
    Jun 17, 2021 at 18:43

1 Answer 1

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There are various things that can cause a motherboard to behave that way.

Two examples include:

A Failed RAM Socket

I've observed those symptoms with two different ~3GHz ATX-era boards (One ASUS M2N-E and whatever that hand-me-down Dell had) when one of the DIMM sockets had gone bad and had a DIMM in it.

In both cases, reseating all the RAM didn't change anything but the system booted perfectly well if I emptied the bad socket, and the DIMM that was in the bad socket memtest-ed perfectly when installed in a known-good socket.

An Incompatible Video Card

I have a P120 that I use for nostalgia gaming which produces those symptoms if I install a known-good Voodoo 3 3000 PCI in the one PCI slot.

I know the slot is good because I've been running it with the onboard video and a 100Mbit network card in the PCI slot.

I know the card is good because it works in the P233 that it was purchased for... so my only guess is that the board with the P120 implements an earlier version of the PCI spec with some bugs in it.

(I seem to remember the P233's board being listed as implementing PCI v1.1.)

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  • Thank you. It doesn't seem to be the RAM. I tried another video card, an ET6000, but nothing happened. Even without any CPU, RAM or VGA the power LED won't light up. Someone said it might be the chipset. Well, maybe... This needs proper testing.
    – Tamás Polgár
    Jun 13, 2021 at 22:53

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