Nine Ball - ball lock issue

[roadshow16]

Any help appreciated. I have an issue on my Stern Nine Ball, where I light lock on the left and lock a ball, all fine, kicks another ball into the shooter lane. Relight lock and get the ball back in the lock, so 2 balls are locked, all good. Kicks another ball into the shooter lane, I plunge and then the bonus count starts as if it's end of ball. No multiball. The 2 ball multiball when I hit the roving target works right, it's just when 2 balls are locked that the issue arises

 

[Ashbo]

Any help appreciated. I have an issue on my Stern Nine Ball, where I light lock on the left and lock a ball, all fine, kicks another ball into the shooter lane. Relight lock and get the ball back in the lock, so 2 balls are locked, all good. Kicks another ball into the shooter lane, I plunge and then the bonus count starts as if it's end of ball. No multiball. The 2 ball multiball when I hit the roving target works right, it's just when 2 balls are locked that the issue arises

I know nothing about this pin, but smells of trough switch on when it shouldn't be?

 

[DRD]

+1 on trough switch fault

 

[Wayne J]

Specifically, the switch for ball 3, if it's performing correctly in all other situations.

 

[roadshow16]

Great, thanks guys