James,
It sounds like you may have a bad processor board ...not sure if that is what also damaged the EEPROM.? Still could be another issues ....second on my list is the memory board? which on the 8920A has the firmware and the NVRAM ( battery backed up )
Firmware should throw? a checksum error if it was bad or not reading correctly ...you already tried that and didn't have those errors anyway.
If you put in a blank write enable EEPROM you will also see numerous checksum errors on the initial start for the calibration data but on the second boot that should be gone since default data was loaded in.? check in your programmer options that the EEPROM is software write enabled ....sometimes that is a setting you have to enable.
If it was the EEPROM causing the initial error that should have fixed it ...the diagnostics will fail with the default calibration? data.
At this point if you were in the US I would suggest sending it in for repair.
The initial problem can be fixed and the calibration may be recoverable but it sounds doubtful at this point.
Blown calibration data may turn the unit into parts since the effort to recover factory tuning may be more trouble than the unit is worth.
Still has value as parts ...just not as much as if the calibration was good.
