Replace a shorted coil before firing a repaired driver
Powering up with a coil that reads near 0 ohms will destroy a newly replaced driver transistor the first time the coil fires. On System 80 a low coil usually means everything in its ground path is suspect too: the under-playfield transistor, the driver board transistor and any pre-driver.
Systems
Related tips
- Test an under-playfield 2N5875/2N5879 coil transistor
- Coil stuck on that is driven through a playfield-mounted power transistor
- First power-up, step 5: add the driver board, then coil power
- Haunted House driver board: which transistor runs which coil
- Black Hole driver board: which transistor runs which coil
- Driver board coil connectors A3J4, A3J5 and A3J6 (HH and BH)
- Diode-test a driver board 2N6043
- Diode-test a driver board 2N3055
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)