The drive transistor on a pop bumper driver board burns out again after being replaced.

Gottlieb pop bumper driver transistor keeps burning out: check the coil's diode

Cause: The diode on the pop bumper coil had failed, so the coil's back voltage destroyed the transistor. The fuse feeding it was also the wrong value, so it did not protect the circuit.

Checks

• Check the diode on the pop bumper coil (and the coil resistance) before fitting a new transistor.
• Check the fuse for that circuit is the value in the manual.
• Make sure the ground improvements for these games have been done.

Fix

• Replace the coil or its diode, fit a new TIP102 (a TIP101 also works at this voltage), and fit the correct fuse.

Systems

• Gottlieb System 80B

Related tips

• Use a TIP102 in place of the pop bumper board's 2N6057
• Same coil driver transistor keeps blowing after replacement: counterfeit TIP102s
• 20-second test for shorted coil driver transistors
• STNG: diverter coils lock on during play
• Kickout coil burns up in attract mode: driver transistor, resistor and the CA3081 at U3
• The 19 solenoid driver transistors
• Testing the 2N6043 coil drivers
• Solenoid driver transistor types

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