The crystal is a 14.318Mhz, cap ce26 is same as ce28. The resistor appears purple-green-gold-gold or 7.5ohm 5% and looks like a 1/2watt. Not sure about the diode or FET, my board is in storage....

D1= 1N5817
Q14= PBYL1025B
the big resistor is 1watt.

Karbist wrote on 2025-04-13, 01:34:

D1= 1N5817
Q14= PBYL1025B
the big resistor is 1watt.

Thanks ! saves me from a drive and digging into boxes 😀

Thanks for your help, I will order these and hope this will bring back life in this board.
When finished I willet you know if I was succesful.

Parts are ordered, but the PBYL1025B is only sold by Utsource, who I don't trust 😐

Ordered a few anyway, hoping they are legit because there are no other alternatives.

To be continued......

Update:

Board got a good clean.
Received all missing parts this week and placed them on the board.
Also did a repair on a broken trace at the underside off the board, under simm slot 2.
No shorts found anywhere on the board after thorough inspection.

Inserted post-analyzer card, first without CPU and memory for a smoke test. Succesful.
Then inserted a Celeron in a slotket and, yes postcodes appeared stopping at C1.
Added 1 memory bank and post code stopped at 00.
Also with a graphics card it stays at 00.
I rebooted couple off times and only once ended up with a booting system getting me in bios. It recognized the CPU and memory correctly!!!!
After that.....keeps hanging at post code 00.
Wiggled the slotket adapter, resoldered the joints, reseated several times.

So system showed me it is capable of booting, but something is holding it back. Dunno what, so love to get your thoughts on it!

Can you post some high resolution pics of your board as it is today so that the community can try to help look for any other missing components?

Have you checked for bent pins inside the CPU slot?
How did you clean the board? Did you wash it with soap and water?
Did you remove the BIOS rom chip before cleaning? (Make sure it's properly seated again)
Perhaps you can give the CPU slot another clean with Isopropyl alcohol and a brush that can reach into the slot (be careful not to damage the pins in the slot), just to be sure that the pins are properly clean because you could get this kind of behaviour if the CPU is not making a good connection.)
Also, give those memory slots another clean with the isopropyl as well.

Do you have an eprom programmer to reprogram the BIOS in case there is any corruption?

Did you connect a PC speaker and do you get any beeps when you have no memory and no display card installed?

Were you using an AGP or PCI display card?

Did you ensure that all jumpers / switches are properly configured?

byte_76 wrote on 2025-04-25, 20:24:

Can you post some high resolution pics of your board as it is today so that the community can try to help look for any other mis […]
Show full quote

Can you post some high resolution pics of your board as it is today so that the community can try to help look for any other missing components?

I will post it

Have you checked for bent pins inside the CPU slot?

yes, I have checked

How did you clean the board? Did you wash it with soap and water?

With soap and water

Did you remove the BIOS rom chip before cleaning? (Make sure it's properly seated again)

Yes, I removed it before cleaning

Perhaps you can give the CPU slot another clean with Isopropyl alcohol and a brush that can reach into the slot (be careful not to damage the pins in the slot), just to be sure that the pins are properly clean because you could get this kind of behaviour if the CPU is not making a good connection.)
Also, give those memory slots another clean with the isopropyl as well.

Will do that

Do you have an eprom programmer to reprogram the BIOS in case there is any corruption?

I'm afraid not

Did you connect a PC speaker and do you get any beeps when you have no memory and no display card installed?

Yes, beep codes where accordingly

Were you using an AGP or PCI display card?

Used a working AGP card

Did you ensure that all jumpers / switches are properly configured?

Yes, tried auto-config (all switches in off position) and configured for Celeron 500 MHz.

The board after placing missing components.

Was thinking, maybe to check capacitors for their values, maybe the repair on the broken trace.

Are those broken traces?

byte_76 wrote on 2025-04-26, 11:09:

Are those broken traces?

They have continuety.

Disable the jumper free mode by setting the Jen jumper to 1-2 position and manually set the FSB to 66mhz and 2x multiplier, see if it makes any difference.

Disabled jumperfree option, cleaned CPU slot with isopropyl alcohol and a small brush.
Also checked capacitors. They are Rubicons and check out ok. Double checked damaged traces, but they all have conductivity, including the one I already repeared.

Tried a Coppermine CPU. No succes, but the voltage regulator on the motherboard switched nicely to it's 1.65 volts and with the Celeron to it's 2.0. volts

During couple of boots the post codes got a step further to error code 07, but could not get it again. Still hangs at post code 00.

Another thing crossed my mind.
Could I have used the wrong crystal, which I harvest from an socket 478 board?

That crystal has the correct value, you should have around 1 volt or 14.318Mhz on each leg when it's oscillating.

Crystal is working as it should.
It seems I get different results in post codes when I move the processor in it's slot. So I guess some pins have a bad connection. Going to heat the pins with the heatgun a good idea?

I have a non-working P3B-F as well, mine hangs at C0 with two dashes after. I'll watch this thread in case someone finds a fix.

rolierop wrote on 2025-05-24, 11:17:

Crystal is working as it should.
It seems I get different results in post codes when I move the processor in it's slot. So I guess some pins have a bad connection. Going to heat the pins with the heatgun a good idea?

Deoxit spray on both slot and cart then just insert and remove a few times, clean the cart and test the board again.

I cleaned the slot again thoroughly, reseated the CPU a bunch of times.
The post-analyzer card gets pased C0 and C1, so memory is seen. If I remove the memory it hangs on code C1. But after C1 the next code is 00 and it stays at that.
So to me it seems the processor is working or else the post analyzer card could not do anything. Processor also gets warm.
Code 00 does not seem to mean anything??

After using the reset on the motherboard, instead of power cycling, it suddenly got to 0c (no keyboard) and 0d (no video adapter) and one time even past a bunch of other codes.
So, connected them, but still no video output. And then hangs at 00 again.
Sometimes ago i did get into the bios, but that was only once.

Maybe a recap?