Was dealing with a pretty janky Bowling Alley mech. Stuttering at the end of sweep, jerky movement when going side to side. I wanted to see what was going on and this is what worked for me. Before going through all these steps, you may want to do a quick switch test on the bowling alley mech to make sure they are registering. If not, you may need to adjust a switch as well.
I removed and reinstalled the orange launcher about 6-8 times trying to figure out what was going on.
First thing you need to do is pull the orange launcher. You can access it through the gap between the two motor mounts under the BA PF on the right side. There is a 2.5 mm set screw holding the launcher to the motor shaft. unloosen that and the launcher should pull straight up and out.
On the orange launcher there are 3 screws holding two plates to the bottom of the launcher. Remove those screws and plates. you will see a metal collar inside the orange launcher with the set screw. On my game this collar would move freely inside the orange launcher, only stopping when moving side to side, by the head of the set screw. This may be what was causing the miss hits to the pins, (computer thinking the motor is in a different position due to it floating in the orange launcher), and I am sure this play inside of the launcher was causing the stutter at the end of the right sweep.
The fix....I gorilla glued my collar back inside the launcher. Its tight now and after a few test balls look like hits are registering very well. We'll see in a week or so how my fix holds up.
***When reinstalling the launcher back onto the motor shaft, pull those two switches back and slide the launcher down. you will see two holes under the switch blades where you can put a small screw driver or allen and pull the switch back while dropping the launcher in. would be great to have a 3rd hand to help with this part so grab a friend.****
also, when reinstalling the launcher, I put the launcher back on the shaft and then brought it up from the bottom just a mm or so. Also, When testing, go into the menu, put the ball in the launcher, and run the test.