Remove J13 from the driver board and see if the coil still locks on. If it does, you have a board problem. If it does not, you have a switch and or wiring problem.
Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside