Hm. Couple things to bear in mind with the 128XP -- serialized prom, CVC battery backed ram. The two boards in the system that are linked by their components are the OC3 and CVC. On the OC3 there is a small serialized prom which communicates with the CVC and acts as the key for the encryption strings. The reason you had the 'prototype system software' alert was due to the fact that you took the serial number out of the system and put a new one in. It tried to activate the system's options... but couldn't because it was the wrong key.. comprende?
Promload 04 and 05 are slightly harder to nail down as they're basically just alerts saying 'couldn't load software off of a PROM'. I've mainly seen these when OC software chips are corrupted.. but it could be a number of things.
Just to recap on what has been tried so far:
-- minimum config results in promload 05 or promload 04, dpr 80.
-- error 9 (scanner low voltage) cleared up due to reseating, problem seems to be in the scan converter now
-- different OC3 pcb.
As for what's left to try... maybe the scan converter power supply, check the syscon revision level on the OC3 from the XP4, and the one from the XP10. The whole XP4 thing is only an issue when you swap the MEX3 boards -- they contain the transducer microcode. If you wanted to be thorough, you could swap the CVC and OC3 from the XP4 into your XP10. That should allow it to boot.. then you can try the OC3 from the XP10 with the CVC from the XP4.. etc.
Let me know what your'e able to find and we'll go from there.
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