Chadti99 wrote on 2022-03-26, 22:21:

I could of sworn the first couple boot attempts the keyboard lights were solid and now they only flash briefly. I connected a post diagnosis card with speaker and I’m not getting any beeps or codes. The board looks immaculate so hoping I can still salvage it.

what exact make/model is the board AND can you take a picture looking straight down on the board ?
Actually having the KB lights briefly flash is what is supposed to happen. If on solid that is a bad sign.
Have you tried the post card in a ISA sot ? Most PCI need the Diag card in a PCI slot but knwoing what happen in ISA might help...
There is no ram and are no cache chips (not that it should prevent most boards from booting with an error code)

This is the same failure mode I experienced this past week before my motherboard went up in smoke.

One of my computers caught fire today

It's possible that there is a short on the motherboard and the power supply is shutting itself off due to short circuit protection. Can you hear a *click* sound from the PSU, like a relay is being tripped? I'm not sure if it's actually a relay as part off this mechanism, but this is what it sounded like from my power supply.

Test for continuity between all voltage rails on the AT power pins and ground to see if there is a dead short.

turn on, wait 10 secs, put finger on the big black chips on the mobo
if its boiling hot.... sorry

why are you using a kingston upgrade cpu, the mobo looks like it has a voltage regularor

Get an SX33 or something equally undesirable, put it loose in the socket so it's standing a couple of mm out, bring the lever over near to lock and scrunch the CPU into the socket, repeat a few times.

what revision is it?
some of those boards only accept FPM ram, not EDO

Horun wrote on 2022-03-27, 00:46:

what exact make/model is the board AND can you take a picture looking straight down on the board ? Actually having the KB lights […]
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Chadti99 wrote on 2022-03-26, 22:21:

I could of sworn the first couple boot attempts the keyboard lights were solid and now they only flash briefly. I connected a post diagnosis card with speaker and I’m not getting any beeps or codes. The board looks immaculate so hoping I can still salvage it.

what exact make/model is the board AND can you take a picture looking straight down on the board ?
Actually having the KB lights briefly flash is what is supposed to happen. If on solid that is a bad sign.
Have you tried the post card in a ISA sot ? Most PCI need the Diag card in a PCI slot but knwoing what happen in ISA might help...
There is no ram and are no cache chips (not that it should prevent most boards from booting with an error code)

Revision 2.1, pic attached.

When I say flash, it’s like a millisecond, not the full on bright for one second usual deal and then off.

When I try the post card in the ISA slot it has one less LED lit I think, I’ll get a pic of this as well.

BLockOUT wrote on 2022-03-27, 03:15:

turn on, wait 10 secs, put finger on the big black chips on the mobo
if its boiling hot.... sorry

They are warmish but not hot really.

BLockOUT wrote on 2022-03-27, 03:16:

why are you using a kingston upgrade cpu, the mobo looks like it has a voltage regularor

Was just a quick way to test if the CPU socket was getting any kind of power.

BitWrangler wrote on 2022-03-27, 03:18:

Get an SX33 or something equally undesirable, put it loose in the socket so it's standing a couple of mm out, bring the lever over near to lock and scrunch the CPU into the socket, repeat a few times.

Interesting, what does this do exactly?

Kahenraz wrote on 2022-03-27, 02:50:

This is the same failure mode I experienced this past week before my motherboard went up in smoke. […]
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This is the same failure mode I experienced this past week before my motherboard went up in smoke.

One of my computers caught fire today

It's possible that there is a short on the motherboard and the power supply is shutting itself off due to short circuit protection. Can you hear a *click* sound from the PSU, like a relay is being tripped? I'm not sure if it's actually a relay as part off this mechanism, but this is what it sounded like from my power supply.

Test for continuity between all voltage rails on the AT power pins and ground to see if there is a dead short.

Not hearing any noises from PS. I’ll check for shorts as mentioned! The PS does work with other boards for sure.

Thanks ! very clean looking board. Makes me think the BIOS chip is bad or has failed.

Horun wrote on 2022-03-28, 02:33:

Thanks ! very clean looking board. Makes me think the BIOS chip is bad or has failed.

Yep, would have thought the same. I’ve tried several different bios versions and two different brands of EEPROM. Still no go.

Question for you. What is the value on the network resistor by the cpu socket? I'm trying to find one for this motherboard which I just picked up.

Thanks!

If these are used to adapt for different CPUs they are usually not resistor netwotks but a combination of 4 jumpers.
They are very hard to find today but you can build them yourself or use 4 single jumpers made of thin wire.

It's hard to tell, but is it in a socket? I wonder if a male-to-male pin header will fit. Then you can just use jumpers on the exposed side.

majestyk wrote on 2022-06-29, 05:21:

If these are used to adapt for different CPUs they are usually not resistor netwotks but a combination of 4 jumpers.
They are very hard to find today but you can build them yourself or use 4 single jumpers made of thin wire.

I believe this is the correct answer.

It's in a socket, but it is smaller than the pins on say a ide ribbon pin. It is more the size in diameter of a normal resistor. The issue with the network resistor is they come in different circuit types the B type are just straight jumpers of 1-2, 3-4, 5-6, etc... But the non b types are different. Which is why i asked.

It's really weird that they used that resistor component instead of a regular pin header and jumpers. Surely this would have been cheaper.