Check to make sure there is a ball in the upper acrylic structure. There should only be 1 ball being held in the upper structure.
If there is more than 1 ball - there is a problem with the micro-switch that shuts off power to the second vertical elevator.
Check to make sure that the micro-switch in the upper acrylic structure is connected and working properly.
Ensure there is proper length on the switch wire and that it clears the acrylic.
Check power and signal to the ball-release solenoid.
***Older games will show Err-19 instead of L-***
Please see information under L-error