but the likelyhood of that is fairly small. Still possible, yes... but small... the circuitry is way too simple. Now if this were a color monitor, all bets are off...
You need to try and find another logic board, even if its a regular SE. This will help point yourself in the right direction, otherwise I see you chasing your tail in circles all day long.
Without that, the only other option is using a scope and watching the signals coming from the logic board, but then you need a known good board to compare the waveforms to.