Hi DC
Do you have the schematic drawing for this Pinnie?
In case you are not aware be careful poking around machine with
The power on, if it's like mine of similar era there will be 240v on
some relay and score motor contacts which reset the drop targets.
I had a similar problem around 6 months ago and finally traced it to
A contact that on close inspection looked closed but was not conducting,
5 sec to clean and all was good, took me hours to find and needed schematic
And multimeter to trace to the culprit.
Cheers
Dave