Quoted from CUJO:Yikes!
Seems to happen only before bullet catch and the ball goes into the stage and locks.
Is there a way to test to be sure it's the mech and not the software?
If the stage door is opening and closing and the captive ball is successfully allowing the locked ball to drop through to the subway (feeds the scoop lock/kickout) I don't think you have a defective motor or assembly. Can you better explain what happens? Bullet Catch should progress like this:
Stage is open and captive ball is in the "hold" position.
Ball enters stage, door closes, mode starts.
Captive ball lowers (you can't see this as the stage is closed) and drops ball into scoop lock.
Ball is released into play, depending on where you have balls locked this may come from the scoop, the left lock or a new ball from the trough is ejected from the shooter lane, this is random but most often will be from the scoop.
Right inner lane is lit to "load the gun"
Hit right inner lane, ball is diverted to VUK, kicked over to the lower catapult and shot into the trunk. Trunk diverter should not open thereby "locking" the ball in the upper catapult.
New ball is entered into play, again this could be from any of the three possible locations.
Shots are lit, one at a time from left to right, starting with the Milkcan loop, moving to the left orbit, stage alley, key lane, etc. until you hit that shot which will then "fire the gun and catch the bullet" and start a two ball multiball by launching the ball from the upper catapult into play. During this MB whatever "fire" shot you scored and the right inner loop will score your bullet catch award until you lose one ball.