In multiball, after two shots to the centre hole, the third ball is loaded into the left cannon and the cannon won't rotate. Cannon test, switch tests and a new 16-opto board all look fine.
Cannon won't turn on the third multiball shot though it tests fine: flaky opto wire
Cause: An intermittent wire to an opto in the cannon assembly that only opened with the cannon in a certain position.
Checks
- Leave the game in switch test and move the cannon while watching its optos.
- Check the gun home and mark switches.
Fix
- Repair or replace the faulty opto wiring in the cannon (replacing the cannon's wiring loom is often quicker than chasing each joint).
Systems
Games
Related tips
- Turn ends while a ball is still in play in Final Frontier: flaky trough opto
- Eddy sensors: electronic ball switches under the playfield
- All playfield optos dead after replacing one opto: failed 16-opto board
- Indiana Jones to Demolition Man games have two LM339 opto boards
- Adjusting an STNG, Theatre of Magic or Roadshow eddy sensor
- Eddy sensor board R1 values by game
- Optos test good but still don't work: the opto board
- Testing optos in switch edge test
Source: Pinball Repair help group!! (Facebook group)