One coil driver transistor (here the pop bumper driver) fails again soon after each replacement, even though the coil, its diode and the pre-driver parts test good and another board drives the same coil without trouble.

Same coil driver transistor keeps blowing after replacement: counterfeit TIP102s

Cause: The replacement TIP102 transistors, bought cheaply online, were counterfeit and could not handle the coil current.

Checks

• Measure the coil resistance and check its diode.
• Check the pre-driver transistor and resistors for that driver.
• If everything checks out and new transistors still fail, suspect the transistors themselves.

Fix

• Replace the transistor with a genuine TIP102 from a reputable electronics or pinball parts supplier.

Systems

• Williams System 11B

Games

• Taxi

Related tips

• CPU and driver board transistors by position
• Use TIP102 when replacing a TIP122
• Quick check of all TIP122/102 drivers before first power-on
• Gottlieb pop bumper driver transistor keeps burning out: check the coil's diode
• Kickout coil burns up in attract mode: driver transistor, resistor and the CA3081 at U3
• Lock diverter locks on at power-up and gets hot: shorted driver transistor Q22
• TIP102 is a good substitute for SE9302 coil drivers
• Use a TIP102 in place of the pop bumper board's 2N6057

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