Can you check the markings on the coil? It might be incorrect for the unit.
For the opto, I usually check for any broken wires as they are quite light gauge, then reflow the solder first as its quick and easy and 90% of the time I have found cold solder joints on optos to be the culprit. While there, with a qtip and some windex, gently clean the sender and receiver in case one is dirty and check in the switch edge test if it registers when the ball is dropped in.
