thanks brett for the credit.
I found it strange that when you captured the ball it would ask you to lock a second ball when there was no other ball on the playfield, then the pin would go into ball search mode and kick the captured ball out. but the pin never said that there was a missing ball either. and it would always start when you pressed the start button. the problem would only occur when after you lost 3 of the 4 balls in multi ball, the 3rd ball would get stuck on the switch and not press the switch down, but when you lost the last ball it would knock the 3rd ball and the 3rd ball would press the switch down properly. it would only do this with the playfield in the normal play position, if you lifted the playfield up it would work fine and not get stuck. I did a switch test with the playfield down and simulated loosing 3 balls by putting 1 ball at a time into the ball trough, I noticed that the 3rd switch was not registering, but when the 4th ball was dropped into the trough the 3rd and 4th switch would both register at the same time so i adjusted the 3rd switch and all was fine when i did the switch test again.