dont insert it too far, the hits will all be striking the boltworks, dont insert it too little it will not hit the last pin
try a simple deadbolt, this should go easily.
padlocks are smaller keyways so the deadbolts are the best practice.
I have heard that if the vibro pick runs too fast, it can make the pins float on top of the hits and never fall far enough to reach a shearline
One thing you can do to test this is take those new batteries out and put in some worn batteries,
look at the keyway look where the pins stop in that warding, and see if you can put the needle under them,
it might be that the keyway wards are in the way, try striking straight up then try again with a right tilt
the try again with a left tilt.
Thats all Ive got, hope it helps
.....got bored with it...