Opto ball troughs from Indiana Jones on
Every WPC game from Indiana Jones on uses opto switches in the ball trough. Indiana Jones through Demolition Man use an earlier trough opto board that carries LM339 chips, which fail; later boards do not.
Systems
Related tips
- Optos test good but still don't work: the opto board
- Confused switch matrix from LM339s on opto boards
- Checking an under-playfield opto board for bad LM339s
- Two LM339s on the Fliptronics board read the flipper optos
- Opto switches dead all at once
- System 11B opto board fails with good optos
- Weak or dead flippers from failing LM339s on the Fliptronics board
- Phantom or erratic switches traced to an opto driver board
Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Two, Clay Harrell (pinrepair.com)