A lamp row stays dead or stuck after its row transistor and the matrix resistors have been checked.

Lamp row still dead after a new TIP122

Cause: The row drive chain: 7406 chips at 11F and 12E, the 2N5060 SCRs at Q81 to Q88, the diode on the CPU board for each row SCR, or the PIA at 11D.

Checks

• Diode-test the row diode on the CPU board.
• Test the 2N5060 for that row.
• Probe the 7406 outputs.

Fix

• Replace the failed diode, SCR, 7406 or PIA.

Systems

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

Related tips

• Lamp and switch matrix transistor positions on the CPU board
• CPU flipper enable relay RY1
• Lamp matrix still wrong after replacing transistors: upstream parts
• Lamp matrix row test at 2J7 with Leon's code
• Lamp rows stuck on: the 7406 at IC19
• Test a 2N5060 lamp matrix SCR with a meter
• Lamp matrix fault with good transistors: check R55 to R62
• Lamp driver SCRs on the CPU board

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