I did some further testing and diagnosis and I think I found culprits: CPU and RAM sockets. I get intermittent issues where it either doesn't beep or it has a long beep, pauses, and repeats.

I recently put together a P2B-F based system. Very nice board. A couple things to double-check:
: The AGP multiplier jumper, next to the IDE connectors labeled AGPFS, should be on 1-2. One of mine had it on 2-3 and it would not post, even though I wasn't using an AGP card.
: The KBWK jumper next to the battery holder, on 2-3

Besides those, and the cpu clock and multiplier jumper blocks, all other jumpers are off.

I clean Slot 1 and ram sockets by dousing a thick business card in IPA and inserting it along the socket length. Almost always comes out black.

I'll do that with IPA and see what happens. I have the jumper for AGP set (2-3 for the 66MHz FSB, and 1-2 for the 100MHz FSB). I don't have any AGP 2x cards, but I know the TNT2 M64 is compatible with 2x (tested that theory on my Socket 370 system).

Use a pencil eraser to clean the contacts of both the CPU and the RAM.

Bringing back the old, cold, forgotten post. I inserted a POST card in the PCI slot and got a code 00C1, indicating bad RAM, no matter which ones I install, plus, they all work in my Socket 7 and Socket 370 builds. Sometimes, random ones would appear, however, it's still not working. The keyboard LEDs would all stay lit if the code is either C1C0 or 00C1, any other ones and the lights go away. Still get no video out using either a PCI or AGP card.

Might clean the CPU slot and the RAM sockets again once the time is right.

Culprit to me sounds like capacitor issues and none of them imploded.

I have attatched two older BIOS files since you asked for them in your first post.
Maybe try a new EEPROM? I have wrongly inserted two BIOS EEPROMs yet and they were both gone within a second. You say it tests fine in your programmer but we know how weird things sometimes get with those parts, so if you have a spare...

Is your slotket configured correctly for the 400MHz PPGA Celeron? Some slotkets have jumpers to switch between FCPGA and PPGA.
Have you tried another CPU and or slotket yet?
Have you also tried running the motherboard with only CPU and speaker connected (no RAM or cards)? What's the result?

Sorry if some of those are unjustified noob advice. 😉 Good luck! 😀

It's a standard Slot 1 Celeron 400/66 CPU. Going to buy a new EEPROM programming tool and some chips.

bjwil1991 wrote:

It's a standard Slot 1 Celeron 400/66 CPU.

Sorry, I don't know why I thought I read you were using a slotket.
Have you tried another CPU yet or is this CPU known working?

Edit: Some pin compatible EEPROMs don't work well with some Asus P2B(-F) boards and produce errors creating DMI pool data. The original Winbond W29C020 is guranteed to work.

I don't have any other Slot 1 CPUs, let alone a Slotket 370 adapter. I wish I could find one that supports Tualatin 1.4S CPUs since those can bring the voltage down to 1.45VDC or possibly on its own with the board, but, I don't think the board supports lower voltage at any rate. Plus, I need to buy a Slot 1 bracket since the board doesn't have one, sadly.

The CPU gets warm to the touch when powered on (I have a MacGyvered heatsink fan combo installed and the heatsink gets warm after leaving the system on for a period of time.

For testing and troubleshooting the plastic mounting parts aren't usually needed. Lie the board flat down and keep the CPU somewhat upright with your finger. 😁
You can find Pentium II 450 CPUs for below 20USD on US ebay right now. The PII450 is somewhat collectible so you shouldn't have a problem reselling it in the future. There are also other Slot1 CPUs for <5USD avaliable that are perfect for troubleshooting. 😀
I'd like a Tualatin slotket as well but I don't think I'll find one for a reasonable price anytime soon and realistically speaking there's no real reason to run a Tualatin 1.4S on a BX board anyway; anything that profits from the 440BX will run just as well with a 1GHz Coppermine and anything that needs a faster CPU can be run on a P4 or Athlon (XP). The 1.4S is also not worth the headache of the 89MHz AGP clock. So don't worry about it. I try not to as well. 😉 🤣