Measure every coil before powering up new driver transistors
A coil that has overheated can burn its enamel so neighbouring turns short together, which drops its resistance. A Data East/Sega coil reading below about 3 ohms will destroy freshly fitted driver transistors almost immediately, so check all coils with a meter and replace any under 3 ohms first.
Systems
Related tips
- Re-measure the coil after replacing a shorted driver
- 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
- Check every coil's resistance before first power-up
- Fit a coil diode with its band on the power lug
- A low resistance coil means checking its driver chain too
Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Two, Clay Harrell (pinrepair.com)