A low resistance coil means checking its driver chain too
When a coil has shorted, replace the coil and also expect to replace the driver transistor and its pre-driver in that coil's ground path.
Systems
Related tips
- Check every coil's resistance before first power-up
- Always check the coil diode when a driver transistor has failed
- Finding a coil's driver transistor without a manual
- Constant power coil drivers Q8-Q13 and Q23-Q30
- Use the manual's coil/flasher chart to find driver transistors
- Low coil voltage from pitted L/R relay contacts
- Special coil stays on even after replacing its driver chain (Rev 3)
- Solenoid driver layout: 16 multiplexed plus 14 constant
Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part One, Clay Harrell (pinrepair.com)