National Instruments NI PXIe-8133 i7 Quad-Core Controller For Parts Not Working

Description

The original OS on this controller was Windows 7 Pro and max RAM 8GB.  Physically, the front of the unit looks good (no color fading or stains).  The metal plate on the side seems to have a small amount of corrosion.  Backplane connectors are good (no dents or bent pins).
This item was purchased recently in non-working / unknown condition.  I've had good luck fixing items like these but this particular controller will require more time / expertise / luck.  Here's as much as I know; feel free to ask more questions.
After power-on, this controller stops at the BIOS splash screen and PWROK/fault flashes.  NI docs say to reset the BIOS or contact tech support.  Neither of those were successful.  After doing some research, PWROK is "Power OK" and probably a check of the CPU power supply prior to enabling power to the CPU.  (Also, try googling: working principle of the reset circuit of the Intel H55 chipset motherboard.)
One of the more likely culprits is a bad capacitor on the motherboard power supply.  With a schematic one could probably find what to test.  Even without a schematic, someone can probably reverse-engineer where the CPU power supply is and narrow the region of interest to a few capacitors.  The PXIe backplane has standard location for power to the controller.  Following those thick traces should be do-able.
This item does not come with:
- CMOS battery
- RAM
- Hard drive
I'm using them to work on other controllers and they are basic components that are relatively easy to source.