I know this is probably one of the most over-posted issues with STTNG, however hear me out...

While playing (even after "Return to Duty" is no longer lit) a random ball will appear on the playfield. I haven't deduced if it is always from the left vuk or not, but when I notice it most, that is where it comes from. After this happens, obviously two balls will load from then on out usually. I'm assuming this is because the system stores the memory of the -1 ball and tries to stick with it?

anyways, I have checked the trough, all optos 1-6 and up are working fine. The wires are reseated. Are there any other optos I should be checking?

One thing that is weird which MAY help solve this, is every not and then (VERY RARELY), before I even shoot the ball out of the launch ramp, it will say "Lock is lit sir". So maybe there is an opto that thinks a ball is locking? I dunno.

Could it still be the trough even though they test perfect? I don't see or feel any shaky connections.

Cleaned all optos, tons.. hasn't done it in the last few games. Will update later.

Toasterdog I actually read your post which gave me the idea to clean the subway optos. Yes, I cleaned all of them, and that's all I did. Figured I'd do that before I went and bought the GLM boards. Nothing appeared to be wrong with the trough boards, all workin fine. FINALLY got to play a flawless game and destroyed my previous highscore hopefully the issue doesn't come back, those optos were dirty as hell.