DS10 not booting past Initializing GCT/FRU

Hello Managers,

I am having some trouble with getting a DS10 to boot again.
It seemed to be related to an FDDI card which was installed and with which the machine was running well for a long time.
Then, one day, the server failed a normal reboot, and always freezes up after the message

  "Initializing GCT/FRU at <some address>"

Through trial and error, I found that removing the FDDI card solved the booting problem, so assumed it was simply a defective card.
But now I have obtained a replacement, which makes the server behave in the exact same manner. I also transferred all the components to a spare DS10 machine, but still I get the same result.

Has anyone experienced similar problems and has an idea what could be causing this?

Best regards,
Michael Bütow

P.S. The card is a DEFPA-DC.