So I bought a gnr with the trap door coil burnt and missing the linkage. The z connector under the playfiled was disconnected. I have replaced the coil and fabricated new linkage. When I connect the z connector under the playfield and power up machine in blows f7 on the ppb board instantly? Without the z connector for the door coil all other 32v coils work properly. Please help me. Only thing left for fully functioning gnr!

I replaced the bad diode. Now when I power up and go into diagnostics. The trap door fires when other coils do. Knocker, scoop, vuk, eject, ball launch, ball release and 6 ball lockout all fire the trap door also. My coil also started to smoke while cycling through coils... damn it. Any ideas ?

I have the brown wire on the banded side of the diode. I don't c +/- markings on the terminals of the coil? I didnt think it mattered how coil was wired as long as diode the right way ?

So I finally got back to the machine. I still have not been able to solve the trap door issue. The coil locks on soon as I power up the machine. The diode on the coil is good and polarity. Not sure what to look at schematic wise. Help appreciated.