Hey everyone. I'm a noob working with my first machine. The other day a wire came detached from the R flipper. I reattached it, but when starting up a game the flipper fired and was stuck up. The coil quickly overheated and warped. I assumed it was the coil diode (after a lot of research), so I replaced the whole coil with diode. (http://www.marcospecialties.com/pinball-parts/090-5032-00). After replacement, I have the same issue. When starting a game, the coil immediately fires (without pushing the button), is stuck, and starts heating up quickly. I have to unplug the machine to avoid overheating it.
So I've learned that there is a high voltage and low 'hold' voltage for the coil. It appears to be stuck in high voltage when it gets power. I have checked that the switch is not physically active, so thats not it. At this point I believe it may be a transistor on the flipper control board causing the problem. I have no experience testing or replacing transistors, so the easiest route may be replacing the whole board (https://ksarcade.net/rottendog-flipper-control-for-data-east-and-sega-flp023.html). Any other thoughts as to what the issue may be? Thanks for your help.