Constant power coil drivers Q8-Q13 and Q23-Q30
CPU TIP122s Q8 to Q13 drive the six special coils and Q23 to Q30 drive the other constant-power devices. These are not multiplexed, so their power is always present.
Systems
Related tips
- Check every coil's resistance before first power-up
- Solenoid driver layout: 16 multiplexed plus 14 constant
- Always check the coil diode when a driver transistor has failed
- Finding a coil's driver transistor without a manual
- Use the manual's coil/flasher chart to find driver transistors
- A low resistance coil means checking its driver chain too
- A coil has power but never fires
- Special coil stays on even after replacing its driver chain (Rev 3)
Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part One, Clay Harrell (pinrepair.com)