Quoted from gdonovan:

Diving into my first System 11 and have an interesting problem:
High Speed no boot, swapped out the power board with known good and serviced unit and it boots now.. sometimes.
The first couple of power up's the diagnostic digit display on the MPU will be garbled but after a half dozen tries it will boot up and then it is fine. Pulled the EPROMS and made sure the legs were clean and verified contents but does not seem to change behavior.
It is 100% NOT THE POWER SUPPLY BOARD. This is a known good Williams test unit that is fully recapped and extensively tested in a Laser War and Space Shuttle. The original power supply was dead, no 5V output. I'm familiar with working with Data East boards which are similar but the garbled diagnostic is throwing me off as I'm not sure what it is trying to tell me. Pinwiki does not seem to have any info either.
Thanks guys! Aside from a dead switch column and a display segment out the game seems pretty solid.
Gary