Hi guys!
I am restoring a Bally Strikes and Spares Pinball Machine from 1978.
Almost all things are ok i am using a new repro MPU Lisy35.
There is a saucer top right on the playfield.
If the ball enters the saucer closes the switch the right pop bumper starts to hit like crazy and reset will happen!
I have investigated the problem in switch test:
If i push the saucer switch all the switches are activated in the last row at once (right pop bumper, saucer, rollover switch, outhole and SLAM TILT)
Becouse of the slam tilt the game is going to be restarted.
I have checked the switch diodes (not only the last row then all in the machine but they appeared to be good)
All switch seems to be ok from the test except the slam tilt and one coin switch.
No obvious short can be seen.
There are no closed switched what can cause strange behaviour.
I have tried with other MPU board the problem is the same.
For test purpose i have cut down the small switch capacitors (the ones for enhance switch sensibility) from the right pop bumper and rollover but no luck.
I am out of the idea
Please advice!