i'm guessing the rear projection television described above uses three crt guns (red blue green usually)
anyways..
- one of the crt electron guns might be failing
- maybe a piece on the circuit board is old and failing (or maybe an entire circuit is old and needs replaced)
- maybe a controller chip has failed
it goes like this:
the circuit is used to power the crt gun
the controller is used to control the circuit
now, that controller might be in direct control of the crt gun
or
the controller might be closer to the cable input for receiving and 'decoding' the signal.
the problem might be any one of the above, or even perhaps one of the crt projectors needs the gas refilled.
i've seen crt displays opened up and have had gas put...