How the CPU-controlled lamp matrix is wired
Up to 64 CPU-driven lamps sit in an 8 by 8 grid. The 18 V lamp supply is switched on and off rapidly, so each bulb sees roughly 6 V on average. TIP42 transistors switch the 18 V onto the columns, and TIP122 or TIP102 transistors pull the rows to ground. Because the TIP42s supply the current, they fail more often than the row transistors.
Systems
Related tips
- System 11 CPU/driver board transistor locations
- Test each lamp column driver with a test lamp
- Test each lamp row driver with a test lamp
- Lamp and switch matrix transistor positions on the CPU board
- Where the TIP122 drivers are on the CPU board
- Solenoid driver transistor positions on the CPU and PPB boards
- 50 V coils use PPB TIP36c transistors, pre-driven from the CPU board
- Multiplexed L/R (A/B) banks and wire colours
Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)