IFR FM/AM-1200 Checksum Error

[KY5Q]

I just acquired an IFR FM/AM-1200.  It is an older unit, still with the 8031 class processor.  When I power it up, it gives me a "Checksum Error" followed by a "Memory RESET", where it will stay until I tell it to do something else.  I can go into the keyboard and command a frequency, monitor, etc and so far all that seems to be OK.  It has generator, spectrum analyzer and receiver functionality.

I replaced the battery on the CPU card.  I still have the check-sum error. 

I read something about the EEPROMs failing after years of age, so I am willing to update the firmware, if I could find the firmware.  My system has 1 EEPROM, but it has space for two.  I am assuming different firmware loads enables certain options.

If someone has a unit and can read the EEPROMs, and send me the files, I can blow a new set of EEPROMs. Of if anyone has  a presumed working CPU board from a junker, I'd look at this too.  I am trying to get this fixed up to get to a high school that is working on a STEM CubeSAT project.

Ideas?  Regards, Bill KY5Q