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.