When you ran the new wire to the sensor did you make sure you did not cross the wires? The original wires are color coded and must be hooked up correctly. Are you positive it is a sensor problem you are having? Could be a problem associated with changing the gear and not the sensors at all. Please list your symptoms. Does the main light flash 10 times when the door reverses?

Door operates ok if I hold the wall button down. Reverses and light flashes as soon as I let go of the button. Reverses and light flashes if I hold the button down until the door closes. Will not operate from remote. Tried the new wires in every which way (may have fried something?). Old wires are connected properly.

Sounds like you may have fried the logic board. If it were me I would swap the logic board with your other opener if they are the same type. Would eliminate any guessing.

yep - it was the logic board. thanks for all your help!