After the 12 V feed to the poker wheel board was accidentally reversed, the wheel test gives an error: the stepper motor turns, but far too slowly, even though the home opto works.
Poker wheel turns too slowly with a wheel error: hairline crack in a board trace
Cause: Besides the parts damaged by the reversed supply, a large trace between D2 and D9 on the wheel board had a hairline crack.
Checks
- Replace the obviously damaged parts first (the board's LM339, 7805 regulator, filter caps and zener in this case) and test the drive transistors and diodes against their twins.
- Inspect the wide traces around the diodes under magnification and check continuity along each one.
- Compare readings with a known good wheel board if you can get one.
Fix
- Bridge the cracked trace with a wire or solder and retest the wheel.
Systems
Games
Source: Pinball Repair help group!! (Facebook group)