After fitting a new left-right motor and reassembling the T-Rex mechanism, the head still moves in one direction and sticks, and it no longer eats the ball, although the motor turns both ways and all the position switches register.
T-Rex moves one way and sticks after a motor swap: missing e-clip and washer
Cause: An e-clip and washer had been left out of the gearbox, so the mechanism bound up.
Checks
- Check in diagnostics that the head is centred at rest and that left and right go the correct way.
- Check that each position micro switch registers.
- Take the gearbox apart and compare it with the parts diagram, looking for missing clips and washers.
Fix
- Fit the missing e-clip and washer, lubricate the gearbox, and reassemble.
- Recentre the head in diagnostics afterwards.
Systems
Games
Related tips
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- Jurassic Park: T-rex will not turn or its mouth will not grab the ball
- "Ball missing" errors or extra balls served (roller switch trough)
- Left flipper stays up until power off: faulty flipper board
Source: Pinball Repair help group!! (Facebook group)