now one of the real problems with this game, was that when it served the next ball into the shooter lane, it would sometimes add 500 points to the player 1 score and 100 points to player 2 reels, ( this was the scenario happening for a single player game btw)!! this problem had me stumped for ages   so with the aid if the schematic, i worked out that there is a set of contacts on the score motor (1st and 2nd pic show the schematic and the switch in question). from the schematic i worked out that once any of the PF switches are triggered, the power is removed from them by the switch i have arrowed in the schematic and the score motor pics, until the score motor again comes to rest. So what i did was to connect a test light, one lead to the side of this switch that provides power the all the PF switches, and the other to the black wire that runs to all the coils, thus giving an indication of when the PF switches should have power applied to them. The problem seemed to mostly occur when the drop targets were resetting. So next i removed the power to the score motor so i could turn the motor by hand slowly. Then i triggered the switch in the trough so the ball return relay would latch. Now when i moved the score motor by hand, the test light should've gone out before the drop targets reset, but it didnt happen that way!! moving the motor slowly revealed that the targets were resetting about the same time or before the test light went out, which would naturally pulse the 500 point relay as the drop targets reset, because the power wasnt removed from the switches quick enough.

Next post will show how i fixed it.