As no one has offered any direction I will offer somewhere to start. During my recent restore of an earlier pitch and bat sometimes it is the the switch or jones plugs under the front moulding and in the cab body.

With the power off I suggest you use a jumper wire from the score motor to the motor on the pitching unit (this is were a multimeter continuity setting is invaluable). If you have no schematic this may be difficult to see. Possibly from the pitching motor (not the black wire... its a common) you can trace carefully back through the jones plugs to at least the front moulding switch. Turn on the power and see if this helps isolate the bad connection.

Steve J.

If you are still having issues with your machine, you might want to look at the contacts on the pitching motor assembly (mounted under the playfield). That was the culprit on my p&b when I had a similar issue.