Hi folks and thanks for the kind words. This is my first post on this forum. Actually there were other topics that I wanted to comment on, but I had trouble registering. Anyway, hello.
Jensenmann, as Steve Anderson mentioned, check the ribbon cables first, specifically the two short ones that go from the microprocessor board (the board on the right, near the transformer) to the front panel. You might try flexing and moving these slightly while the unit is running. If anything changes on the display while doing this, you have a bad cable.
Also, you could probably "borrow" the long cable that goes to the remote connector, and use it to replace the front panel ribbons, one at a time, to see if the problem clears. If you do this, make notes or take pictures before you unplug anything, and be very careful not to plug anything in backwards.
It's possible to have a problem in the IC's on the front panel, but this is rare. We have never seen a 7-segment display fail on any AMS; it's extremely unlikely that this is the problem. The microprocessor board would be more of a suspect than anything on the front panel. But again, the ribbons are the first thing to check. If they are really dusty and crusty looking, that tells you something. Even if they look ok, it's not a bad idea to just replace them both with new cables, and see what happens.