Compaq and odd pinouts? Where the connector was remotely standard, they always seemed to be normal enough (unlike Dell at in the same period...).

But if you have a continuity tester, it's easy enough to find GND, +5V (power LED) and +12V (fan headers) on the board and compare that to the power pins. Your documentation is ambiguous because of the sheer number of Deskpro models. Ignore that, just look at regular ATX pinout.

You can use a normal ATX power supply with that motherboard.

The power connector isn't wired 100% like a standard ATX connector but close enough, the important stuff is the same. There are some guides listing the diffrences and how to modify but after a quick glance I figured it only mattered if you wanted to use the original Compaq PSU when upgrading to a non Compaq motherboard and not the other way around so I just hooked up an old early 2000 era ATX PSU without any modification and everything worked fine.

EDIT

I found an old post where I listed the diffrences between the Compaq PSU in the Deskpro and a normal ATX PSU. My source was probably "the Internet"...

"the pin that is "power OK" on a normal ATX PSU is 3.3VSB, 3.3V-pin #1 is named "3.3V/RS", COM-pin #8 is named "RTN/RS " and COM-pin #14 is named "Aux COM"."

"Basically a standard ATX PSU lacks some features the Compaq PSU has but it should not short out the board... I have read that some people cant get their PSUs to turn on without building a 3.3VSB circuit using the ATX PSUs 5VSB circuit but I do not seem to have that problem.* If you have a Compaq 118053-001 i440BX motherboard there is a good chance it will work with a standard ATX PSU, The board Im testing now at least work with the ~16 year old Seventeen ST-250PIIP PSU Im using on my test bench at the moment."

*I think this issue only applies when you try to get a Compaq server board that actually needs 3VSB running with a normal ATX PSU. I think Compaq 118053-001 can't even use 3VSB eventhough it's built to be compatible with a PSU providing this voltage when in standby on the pin otherwise used as "power good".

I'm pretty confident that the motherboards in the Deskpro EP/EN series of workstations were purposely built to support both Compaqs own oddball PSUs and normal ATX standard PSUs.

/EDIT

This is a great motherboard and it shouldn't be trashed. My bet is that it was built by Intel for Compaq.