Socket3 wrote on 2025-06-03, 17:29:

No reaction to the power button. No magic smoke either.

I had a simular issue with a Dell PPro motherboard. After forcing the ATX powersupply on by grounding the green wire it started working.

@Socket3:
Have you tried it with an embedded (CR2430 IIRC) battery or without?

Have you tried the boards with a different Socket 8 CPU? The issue could very well be the CPU itself.

In case of no reaction to the power button - check for shorts (if you did not already) on voltage rails coming from psu - mainly +5, +3.3 and +12, but also 5vsb.

well the one thing you may have in your favor is that they are actually both the same motherboard, a VS440FX

Yep ! Need a good coin cell battery for them. They should work with a 200mhz 256k cache, nearly all BIOS for VS440 supported it (The 150, 180 and 200 256k's all came out same time)
What PSU are you using ?
Those old ATX boards may not like some newer PSU's due to changes in atx specs....I have one and think I fired mine up with a newer EVGA 650 BQ psu but can't find the notes right now....

Butt seriously, I have a job and sometimes I just miss my daily search of new threads.

If I had 2 boards, and both of them acted the same way - I would look at other things being the issue. Whenever a board doesn't respond to the pwr-on signal I'd first swap the PSU and make sure tis in working order. I'd then check for shorts on the +5vsb line. followed by forcing power on via plugging the board into the psu and shorting pwr-on directly to ground. but the fact that both are exhibiting the same issue suggests a non-motherboard issue.

Now if the power supply flashes on and turns off immediately - that's sounds like a mobo short.

Ydee wrote on 2025-06-04, 12:07:

@Socket3:
Have you tried it with an embedded (CR2430 IIRC) battery or without?

Both.

appiah4 wrote on 2025-06-04, 12:40:

Have you tried the boards with a different Socket 8 CPU? The issue could very well be the CPU itself.

....unfortunatly I only own 1 single 200MHz 256kb chip...

Archer57 wrote on 2025-06-04, 16:21:

In case of no reaction to the power button - check for shorts (if you did not already) on voltage rails coming from psu - mainly +5, +3.3 and +12, but also 5vsb.

no shorts on either board

Dorunkāku wrote on 2025-06-03, 20:30:

Socket3 wrote on 2025-06-03, 17:29:

No reaction to the power button. No magic smoke either.

I had a simular issue with a Dell PPro motherboard. After forcing the ATX powersupply on by grounding the green wire it started working.

Well, turns out the Dell board will power on normally (I got the front panel jumper wrong) - but it will not POST and the CPU is stone cold to the touch. Post card gives no codes. Messed around with jumpers, cleaning and re-seating components, then gave up.

On the other hand, I tried your suggestion on the Intel 440FX motherboard and BEHOLD!!! It fired up! At first CPU would get warm, but no post. POST card showed no codes at first - at least not over the PCI bus. Intalled post card into ISA bus, and got a "no video card error". Plugged in an ET3000 ISA card and IT POSTED!!!!

After forcing it on once, it now powers on and posts reliably, even with a PCI card!!!

Thank you for your advice!!!

luckybob wrote on 2025-06-05, 03:04:

Butt seriously, I have a job and sometimes I just miss my daily search of new threads. […]
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The attachment eae5d625f15196eb93b7c7f34b58b357.jpg is no longer available

Butt seriously, I have a job and sometimes I just miss my daily search of new threads.

If I had 2 boards, and both of them acted the same way - I would look at other things being the issue. Whenever a board doesn't respond to the pwr-on signal I'd first swap the PSU and make sure tis in working order. I'd then check for shorts on the +5vsb line. followed by forcing power on via plugging the board into the psu and shorting pwr-on directly to ground. but the fact that both are exhibiting the same issue suggests a non-motherboard issue.

Now if the power supply flashes on and turns off immediately - that's sounds like a mobo short.

Thank you for answering my call PentiumPRO-Man LuckyBob!!!

As stated above, the Intel board works after forcing it one the way you described. It now works reliably!

The Dell board on the other hand will not post. No post codes on the analyzer card in ISA or PCI, no beeps, CPU stays cold to the touch...

1/2 boards fixed.

Here's a pic of the Intel VS440FX Venus board in BIOS:

I'm already planning a build, just not sure what to use in it yet. I have two options - a relatively period correct one (64mb of ram, Matrox Millenium II, Creative AWE32, Creative CT6670 voodoo 2 12mb) or a more practical build (STB Voodoo 3 2000 PCI or Hercules 3D Prophet II MX PCI, Guillemot Maxi Gamer 64 same amount of ram). I'm also looking for a nice period correct case for it - I have a few decent ATX tower and desktop cases, but nothing that "screams" Pentium PRO for me.

As a little side note - what do you guys use to cool the CPUs? I don't have any dedicated socket 8 coolers, but I found rectangular socket A coolers fit well and conform to the shape of the CPU. I can cool them with twin 50mm fans "a-la" slot 1 / slot A, or use the fan that came with the cooler witch is 70mm + plastic adapter, and secure the heatsink with a "home made" diagonal "Z" clip made out of 1.2mm thick stainless steel wire (the kind you can use to attach coolers on socket 5/7/370/a sockets with missing centra cooler attachment points).

What do you guys use to cool p-pros?

Personally I've always just scoured ebay for proper socket 8 heatsinks, but that's getting harder and harder to do now

maxtherabbit wrote on 2025-09-02, 01:16:

Personally I've always just scoured ebay for proper socket 8 heatsinks, but that's getting harder and harder to do now

I found something, but it's prohibitedly expensive when factoring in shipping...

One of the pc's i'm getting this weekend in a scrap lot looks kind of early 90's atx - it's giving me pentium pro vibes:

What do you guys think?

Finding a ppro in a beige box is tantamount to finding a virgin at a whorehouse.

Id bet money on a late socket 7, maybe super 7.

luckybob wrote on 2025-09-02, 15:23:

Finding a ppro in a beige box is tantamount to finding a virgin at a whorehouse.

🤣 🤣 🤣

luckybob wrote on 2025-09-02, 15:23:

Id bet money on a late socket 7, maybe super 7.

The case has a slot 1 pentium 2 inside - in fact it looks like it's housing the innards of a Compaq Deskpro EN... Here's a pic:

I'm thinking of emptying it out and using the case for my p-pro build. What do you think?

I have a few vacant compaq cases lying around, one's even from a Compaq Evo D500, basically the same exact case the Deskpro EN uses but painted black and with a slightly different front bezel - I might stick the compaq innards in that, paint it beige with some RAL9016 and call it a day... Alltough I MIGHT have an ACTUAL comaq deskpro EN case in my garage's attic, albeit missing the top cover - witch I could nick from the EVO D500 and respray...

Well, turns out the Dell board will power on normally (I got the front panel jumper wrong) - but it will not POST and the CPU is stone cold to the touch. Post card gives no codes. Messed around with jumpers, cleaning and re-seating components, then gave up.

Sounds like a lack of ATX connection somewhere. I have one motherboard with very flimsy ATX which behaves the same way.

The Serpent Rider wrote on 2025-09-02, 17:53:

Well, turns out the Dell board will power on normally (I got the front panel jumper wrong) - but it will not POST and the CPU is stone cold to the touch. Post card gives no codes. Messed around with jumpers, cleaning and re-seating components, then gave up.

Sounds like a lack of ATX connection somewhere. I have one motherboard with very flimsy ATX which behaves the same way.

hmmm. Maybe I should have a look at the SM chip...

Well pentium 2 is just a 2nd generation ppro. ^.^ and it wasn't too far off from S7/SS7 prediction.

Don't ask us what you should, build. Do what you want. You're the one buying the parts, you're the one that you need to make happy.

That said, I have some notes. ^.^

Ppro was at the transition to the ATX standard. Meaning you need to be prepared to "wing it" when it comes to compatibility, both physical and software. All I'm saying is, do what your heart tells you, and don't get hung up on having something "perfect".