Hi all.

Continuing with troubleshooting this GNR. The knocker (8L) and G ramp flashers (8R) do not work. They are L and R sides of coil no. 8. The knocker was originally disconnected at the coil lugs so I reconnected it. Power wire to banded side of diode. Does not work in test mode or in gameplay. I have the same behaviour with a different CPU board. Grounding the TIP122 on the CPU board makes the coil fire. I have power at the coil lugs. Good continuity from power lug to PPB connector. Also good continuity from drive wire to PPB and from the PPB to the CPU. Fuses are all good. No cracked solder or other dodgy work on the PPB.

Any ideas?

Well this was a weird one. Both CPU boards had the same driving transistor destroyed, which happened to be the one that drove the 8R and L coils. New predriver and driver fixed it.