After a full rebuild with a new coil, the right flipper flips but the hold is weak: it drops as soon as a fast ball hits it. The other flipper has the normal hold buzz.
One flipper flips but has a weak hold and drops when hit: bad transistor at Q16
Cause: The drive transistor at Q16 was bad, so the flipper could flip but not hold properly.
Checks
- Check the EOS switch is gapped to make only at the very end of the stroke.
- Check the plunger reaches the coil stop and the sleeve isn't in backwards.
- Swap coil stops side to side to rule them out.
Fix
- Replace the transistor at Q16.
Systems
Games
Related tips
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- Whitestar: I/O board blanking LED flashes, lamp rows 1 and 3 dead: data bus short
- Won't boot after a board swap, CPU LEDs dark: loose 5 V wire in the CPU power plug
- Upper right flipper only fires on a full button press: that's by design
- Left flipper MOSFET keeps shorting after a few flips: counterfeit replacement transistors
Source: Pinball Repair help group!! (Facebook group)