Replace the pre-driver along with a failed driver

When a TIP122/TIP102 fails, change its nearby 2N4401 pre-driver (NTE123AP) too. A failed TIP36c has two pre-drivers, a TIP122/TIP102 and a 2N4401; replace both. Pre-drivers that test fine can be kept, but they were probably stressed.

Systems

• Data East CPU Version 1/2
• Data East CPU Version 3
• Data East/Sega CPU Version 3b

Related tips

• How a coil or flasher is switched: PIA to TTL to pre-driver to driver
• Quick test for shorted TIP122/TIP102 drivers
• Solenoid driver transistor positions on the CPU and PPB boards
• Three-stage drive for 50 V coils
• Flash lamp stuck on and melting plastics on L/R reversed games
• A coil or flasher comes on and stays on at power-up
• CPU flipper enable relay RY1
• Flippers never work: flipper relay RY1 not pulling in

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Two, Clay Harrell (pinrepair.com)