So to follow up:
Traced the wiring from switches on left sling.
All good back to boards.
Connector had been worked on /!modified.
Reseated the connector.
Slings been working good since.
Kept having flaky segments on player 1 and 3
displays in tens spot.
Happened with old displays also.
Switched displays ribbon cables etc with no
Consistent fix.
Traced all connectors back to mpu and reseated those.
Displays working !!
So I figure I have some cold solder joints on back
of mpu that were causing my problems.
Guess I'll have to pull soon and reflow the the pins on back
Figured that's what it has to be unless someone else has any
other ideas.