The orbit diverter coil comes on and stays on the moment the coin door is closed, even with a brand-new power driver board.
Coil locks on as soon as the coin door closes: transistor shorted by the old coil
Cause: The coil was already finding ground through a shorted drive transistor; the door interlock only switches the coil power on. The old bad coil had shorted the transistor on the new board as well.
Checks
- Test the coil's resistance and replace it if it's bad.
- Remove the driver board and diode-test the transistor for that coil.
- Don't fit a new board until the bad coil is out, or it can take out the new transistor too.
Fix
- Replace the bad coil and the shorted transistor.
Systems
Games
Related tips
- 20-second test for shorted coil driver transistors
- F103 blows instantly: shorted ramp diverter coil; magnet fires the diverter if F104 open
- Testing a coil diode on the driver board
- Taking the power driver board out of the backbox
- Replace the pre-driver along with a failed driver transistor
- A coil or flasher energizes as soon as the game is turned on
- WPC power driver board versions and where they fit
- How a WPC coil, flasher or lamp driver chain works
Source: Pinball Repair help group!! (Facebook group)