Options include:

  - Change to a different gas configuration and then switch back

  - Replace the possibly corrupted "Isodat System.iso" with a backup copy (Should be 30-40kb in size, not 1kb)

  - Open the amplifier housing and pull then plug back each amp

  - Restore from Isodat Version Handler

  - Clean install from disk

  ...

  Here the issue was the power supply circuit board at the top of the analyzer cabinet, specifically the 18 V transformer on that board. It was repaired by replacing the transformer, about $20 for the part.