I've been trying to troubleshoot this for weeks and I'm about at wit's end. When the crane is in the right side position ready to be loaded for multiball lock, crazy stuff starts happening. This is the ONLY time it occurs. As soon as the switch is open again, and the crane moves, it stops firing the shooter lane any time the right flipper is pressed.

When crane right side limit switch is pressed in:

Pressing the right flipper button then the #5 trough switch causes the shooter lane switch to register while in test mode.
Pressing the right flipper button then the #5 trough switch causes the shooter lane plunger to fire while in gameplay AND attract mode.

I've done the following:

Replaced diode on Right Side Crane switch.
Replaced diode on Shooter Lane switch.
Replace diode on Trough #4.
Replaced the microprocessor on the CPU board.
Checked continuity all along the WHT-GRY wire.
Checked 5v and 12v at the power board, they're both fine. Holding the flipper up doesn't affect either.

And finally, just now, used jumpers to connect the pins with connectors for the switch matrix disconnected to jumper the right flipper and right crane limit switch....and then connect the #5 trough switch. Guess what...it still registered the shooter lane switch. This, to me, isolates this to some kind of board issue at this point.

What could possibly be bad on the board that would cause switch crossfiring? I have no idea. This is new to me. There's no alkaline damage anywhere that I can see. I already replaced the microprocessor which was my prime suspect to start with. HALP.

Looking at the schematic, the only thing I can think of is the 6821 PIA or the 4001 ICs...

Bueller? :\

*sigh*

*orders parts and starts shotgunning crap*

Interesting, but not terribly relevant. That guide is more for CPU's that aren't booting. I've never had any issue with this one not booting or even resetting.

Hell no I didn't use diodes, because I'm a MORON! There's no way on earth I'm going to be able to test that WITH diodes. I'm just going to call a tech and let him do his thing. I'm trying to sell this and I'm tired of sinking my time into it. It's just not worth it. I thought diodes when doing individual jumpers weren't needed? Haha.

Don't have a logic probe that I know of. I had one a few years ago, but never had a use for it, and it wasn't a clip type so it was basically useless without shorting out tons of crap.

I barely got my crappy ghetto jumpers on there the first time.. no way I can do that with diodes too without shorting something. I'm just over it. I need a car, not a stupid pinball machine.