Socket 4 P60 system board

Discussion about old PC hardware.

Socket 4 P60 system board

Postby mpe » 2018-6-14 @ 20:49

Hi all. I am new on the forum :)

I've always wanted to build an original P5 based 1993 Pentium system. I know it is not the most practical retro computer. But I want to have some fun with the FDIV bug and refresh some early 90's games.

After some effort, I finally sourced a suitable board. I got it cheaply off eBay and it is new part (new old stock). However, it is an OEM board. Looks like it is from a DELL computer.

1) Can you help me to identify the board?

2) Any ideas about PSU pinout? Could a regular ATX PSU be rewired/passively converted to work with this?

3) Do you know if there is any chance to find a riser card for this board? I found some DELL riser cards on eBay. However, I am not sure if there is a chance that a random DELL riser card that fits in the slot would just work. Some of the riser cards have extra chips on them, different slot configurations, etc.. Any idea what to look for? I would appreciate at least one ISA slot for a sound card as the VGA is included. I believe the CL-GD5430 isn't too shabby VGA for an early Pentium system.

4) Any thoughts about CPU heatsink? Do socket 7 heatsinks generally fit on Socket 4 boards? P5 CPU's are slightly bigger than P5C AFAIK Finding a dedicated socket 4 heatsink seems impossible.
the board
Last edited by mpe on 2018-6-16 @ 22:18, edited 1 time in total.
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Re: Socket 4 system

Postby Deksor » 2018-6-14 @ 21:18

This is definitely not ATX, ATX appeared in 1995 IIRC

As for the riser, since this mobo seems to be some sort of LPX form factor, I guess some LPX mobos uses the same rizer
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Re: Socket 4 system

Postby mpe » 2018-6-14 @ 21:46

Yes. ATX is indeed a few years newer than this. I actually found this page:

and it looks like it could be the same thing as "DELL PENTIUM II and III" connector mentioned on that page. At least the non-connected pin 19 is non-connected and I can measure continuity on all COM pins against ground using a multimeter on my board. So it looks like it is an ATX connector with different wiring (and without 3.3V lines).
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Re: Socket 4 system

Postby jheronimus » 2018-6-14 @ 22:11

Yeah, it looks like an Intel-made OEM board in LPX form-factor. The riser connector looks identical to the one on their Socket 8 LPX board.
Pentium III 800, 256MB RAM, GeForce 2 GTS, Voodoo 2 SLI, MusicQuest /w MT-32, SoundBlaster 16 CT2230 /w SC-55
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Re: Socket 4 system

Postby chinny22 » 2018-6-14 @ 22:56

I'm surprised but quick google of the various numbers on the motherboard doesn't bring up a part number for a Dell xyz.
Another quick google and its hard finding Dell's from that era at all!

But that's what I would spend some more time doing, once we know that the motherboard is say from a Dell OptiPlex 123 then finding matching parts and info will be pretty easy I would think
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Re: Socket 4 system

Postby PTherapist » 2018-6-15 @ 10:17

That does appear to be a Dell LPX board of some sort. The "A02" on the partial remaining sticker seems to refer to Dell's BIOS version numbering that they used to use on practically everything. Pity the rest of the sticker is missing, it may have helped to identify the board. Post Edit: Just noticed the obvious big Dell logo in the middle, so yeah definitely a Dell board lol.

Those Riser cards should be fairly easy to track down, however a suitable LPX case and compatible PSU will be much more difficult. That PSU connection is most certainly not standard ATX and will require a custom Dell PSU.

You might get lucky and find that the more common P2/P3 era Dell PSUs (or available adapters) will support it. If it's anything like my Socket 3 Dell LPX motherboard though, I still haven't managed to find a working PSU for it as the PSUs from my P2/P3 era systems do not work on it. (Though note: they may not work for me as my motherboard could be dead, I have no way of discovering that at present).

If you can find out the correct wiring, you could purchase one of those cheap ATX 20-24 pin adapters and simply cut & splice cables into the correct order. That way you don't destroy a good working PSU just for the sake of Dell's non standard design. I'm going to try re-wiring one of those adapters at some point, to see if I can get my board working.

Try having a look at these:
Dell P2/P3 wiring:

This one seems to be marked as Dell Optiplex wiring, which may be the more correct wiring option:

The front panel connector on the motherboard is pretty standard ATX-like, even though Dell had their own custom plug, so should work with any regular ATX case buttons. You'd just have to take trial and error to find out which pins do what, ie. Power on/off, reset, HDD LED, Power LED.
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Re: Socket 4 P60 system board

Postby mpe » 2018-6-16 @ 22:47

Thanks. I've been googling this back and forth I found this :blush:


According to that post, which shows pretty much identical board, my board seems to be from Dell Optiplex 560/L. It is incredibly difficult to find anything about that computer. Moreover, Dell recycled 560 model number for at least one another computer line which makes searching even harder :(

As for the PSU. I am almost sure that the Dell proprietary pinout listed above is the correct one. A small problem with adapting ATX PSU is that most ATX PSUs don't have -5V line which this board needs. It is needed for ISA slot. However, -5V can be relatively easily made out of -12V when needed and there is a chance it will work even without it. Will see.

Still not sure about the riser card. It is not the LPX one mentioned above as the slot has three keys. I found some riser boards on eBay, they seem to be from newer Optiplex systems. Some are simple while others have pci2pci bridge (Intel 21152) on board. U think I will risk the former...
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Re: Socket 4 P60 system board

Postby amadeus777999 » 2018-6-17 @ 11:09

Beautiful board - looking forward to some benchmarks and screenshots.
The only downside might be a restricted BIOS with meak settings. I had a Siemens/p60 board(D841) with a Tseng and it had so so performance. On the other hand a legendary system... but I'm biased.

Can't help with the ATX - connector or riser card as mine had AT style connectors and the riser I had was acquired from a person who knew that it was the right piece for the Siemens board.
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