Bally Harlem Globetrotters.

Flicker and bogus info appear (such as on the credits area) on displays during display mode and while a ball is in play. In between balls during a game (and during display self-test), however, all displays are steady and display proper info.

Headers reflowed on all displays and on MPU and Solenoid PCB. U20 and U11 have both been resocketed and replaced with new chips on the MPU. HV at 190v, 5v fine at MPU test points, etc.

Also tried with only one display operating at a time in case there was one which was causing this - no change.

Help?

This was caused by a bad 5101 RAM at U8 on the MPU. Weird.