After the game has been on for a while the dot matrix display freezes, then shows distorted images, lines or a few stray dots, while the game itself keeps playing and does not reset. After a power cycle it may be blank or garbled, then suddenly work again.
Display freezes or shows garbage after warming up: reseat the display controller ROMs
Cause: Poor contact at the socketed ROM chips on the display controller board, which shows up as the board warms.
Checks
- Reseat the ribbon cables between the CPU, display controller and display, and the display controller's power connector.
- Feel the main chip on the display controller: it runs very hot, and heat-related faults on this board are common.
- If it persists, measure the display voltages while the fault is showing.
Fix
- With the power off, press down firmly on (or remove and reinsert) the socketed ROMs on the display controller board.
The display supply runs at high voltage; keep hands off the display and its power board with the game on.
Systems
Games
Related tips
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Source: Pinball Repair help group!! (Facebook group)