I would look at the trough switches and all VUK optos. If they're loose or not aligned then lifting the playfield will affect them.Had a few spare hours so I just tore the boards out and reflowed everything and double checked all the continuity and connections. Replaced some fuse holders that had been soldered (?). Checked all the transistors, fine. Booted it up, Eject and Ball launch fired for the first time and it tried to work, however, a ball already lodged in the VUK stayed there the whole game and was never released.
Tried it a second time, went back to the original problem of dry firing the auto fire.
Don't know if this sheds any light on the potential problem? All that changed between the working launch and the non working launch was me lifting and lowering the playfield. Guess I'm looking for loose wires under the playfield tomorrow.
Will do that next. Just had a quick flick through coil test, it feels like I just gained one coil (the ball eject) and lost 3 more (the trap door, 2 lots of insert flashers and the 6 ball lock).I would look at the trough switches and all VUK optos. If they're loose or not aligned then lifting the playfield will affect them.