Does anybody know anything about repairing one of these? I just got one that is completely dead, no signs of life whatsoever. I've tried the normal cleaning routine, but that didn't help. None of the 3 carts I have act any different. I've cracked it open and it appears to be fairly simple, but without a schematic or even pics it's hard to know where to start.

Any help will be much appreciated.
98PaceCar