One flipper stays up whenever the game is on and drops when it is switched off. It started after a fast 5 A circuit breaker was fitted in place of the specified 3 A slow-blow flipper fuse, which had been blowing when the flipper was held.

Pre-Fliptronics WPC flipper stuck up with power on: failed driver TIP102

Cause: With a wrong, higher-rated fuse in place, the overload burned out the flipper's driver transistor (the TIP102) instead of blowing the fuse. Replacing the TIP36C alone did not help.

Checks

• Power off and diode-test the TIP102 and TIP36C for that flipper on the board; a shorted TIP102 shows up clearly.
• Look for a melted plastic fuse clip or other heat damage nearby.
• Find out why the original fuse was blowing when the flipper was held (EOS switch, coil, or other fault) before running the game again.

Fix

• Replace the failed TIP102 (and any other damaged parts), and always fit the fuse type and rating printed by the fuse holder.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix

Related tips

• Pre-Fliptronics games need a driver board with the flipper relay
• Pre-Fliptronics: weak flipper
• Pre-Fliptronics: a flipper does nothing
• Pre-Fliptronics: flippers work even with no game running
• Pre-Fliptronics: flipper lane change does not work
• Flipper buttons not seen by the game (pre-Fliptronics)
• Shorted or open bridge rectifiers
• WPC power driver board fuses and what they feed

Source: Pinball Repair help group!! (Facebook group)