This one has me beat. During game play, when the ball is locked on the left ramp (switch 76) the trough seems to lose track of the balls. So when the second ball drains, it goes into ball search. After a few ball search cycles, the locked ball is released and play continues until in drains. At this point, the bonus is scored and the next ball starts; however, all balls are kicked out into the shooter lane.

Here’s what been done so far:
• Switch test on the trough and switch 76 checks out OK
• Known good opto trough boards have been swapped in
• Known good 7 switch opto board swapped in
• U14 (74LS374) replaced

The game is a re-import running DX-2 roms. The cabinet sticker says 4 balls. The manual says 5 balls. The trough opto board has optos for 4 balls. I guess Williams changed the ball count after the manual was published.

So during game play, when the ball was locked at switch 76 and ball search was running, I raised the PF and put it into switch test. Trough 2 (switch 32) didn’t register. Restart the game and go into switch test and all the switches check out fine.

Help! I’m not sure what the check next.

Ok. I like it. Let's see what happens. I will post an update.

So the fix for this issue was to replace the 4 ball opto trough boards with 5 ball opto boards. This game is a German reimport. It has US roms installed and at boot diagnostics would report a ball missing. So did the export versions go out with 4 balls? The factory label that said to install 4 balls has a label underneath that says install 5 balls. Man this one has made what hair I have left turn gray.