Check your diodes first, then check ohms across the flipper coil. If that is okay, If the flipper moves freely, the voltages are correct on the coil, and your EOS is adjusted properly, but it still does not fire, and you have continuity between your cabinet button and your MPU with ground, then it could be a bad flipper enable relay, otherwise you'd see other coils/switches that share that line on the switch/coil matrix malfunctioning/misbehaving as well. Continuity check will quickly give you an answer there. And if it is the line on the switch matrix, it is probably just a bad 2n3906 that got shorted out on one of the two matrix chains. Isolate whether it is just your cabinet switch first.