I have an issue where my machine sometimes will launch two balls into the trough at the beginning of a turn. The issue is intermittent and occurs most often when one ball is locked in the left diversion ramp (whirlwind). I see there are three switches under the apron and a fourth in the trough. Any idea which combination tells the CPU that there is "no ball" in the trough causing the second to be kicked? Each of the four switches mentioned move freely and appear to 'click' at the point they should be triggered.

OK - Problem solved and it turned out to be somewhat of a head scratcher. The machine was launching two balls into shoot lane only when one ball was locked for multiball. After replacing the outhole and ball trough switches, I still had the same problem - and now multiball was ending early when the first ball was drained in the outhole. I then traced all the wiring diagrams per the instruction manual only to find out that the signal wires to number 1 and 3 trough switches were juxtaposed. Now that it is wired correctly everything is working like a charm. Wish the last owner knew how to read a schematic....

Thanks for the help and input.