Several controlled lamps stay lit all the time and look brighter than the rest, even in attract mode or the "All" lamps test.

A whole row or column of lamps is stuck on and extra bright

Cause: A lamp matrix transistor has failed shorted, so its row or column is powered far longer than the normal strobe time.

Checks

• Run the "All" lamps test: every controlled lamp should flash; note which ones stay on.
• Use the lamp matrix chart in the game manual to see whether the stuck lamps share one row or column.
• Test the matching transistor out of circuit or with the diode test before replacing it.

Fix

• Replace the shorted TIP42 (column) or TIP122/TIP102 (row) transistor.

Systems

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

Related tips

• A row of lamps stays on solid, works if the plug is pushed sideways: repin the header
• Lamp column still dead after a new TIP42
• Lamp matrix fault with good transistors: check R55 to R62
• Lamp row still dead after a new TIP122
• Lamps glow dimly when they should be off
• Test each lamp column driver with a test lamp
• Test each lamp row driver with a test lamp
• How the CPU-controlled lamp matrix is wired

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