I would remove the cables from the power valve servo and start the engine.

Gently run the engine up and down over 3,000 rpm. The servo should sweep from full Low to full Hi.

If it doesn't I'd take the back of the PGM off and have another look and see if its burned the transistors out again. If it hasn't and the wiring looks correct then you need to find another servo motor. If the servo motor is faulty it will of most likely already burn the PGM out again.
_________________
If I have to take the carbs off once more...