I've been sorting out issues on my 91 star trek
.originally i was having display issues .
Certain times only on scoring the display would get jumbled and freeze up..
I decided to install updated game and display roms .
The problem went away and actualy worked perfect ..
Now at certain times never consistently when a ball drains a new ball will shoot into the shooter lane and automatically fire into the pf with no notification on the dmd ect .
I'm going to tear into this issue tonight .I'm wondering if anyone has had this issue or were to start looking.
Thank you..

Will do .. IL check the diodes and continuity.

Switches seem to check out ok...

Well I decided to put the original game rom back in.. and it hasn't done the xtra ball for no reason again ? Gonna play some more games to be sure . Display seems fine...
I can't imagine shooting a ball for no reason back into play after scoring a few million is a revision for the new game rom ?