First make sure it's not just a vibration issue. Go into switch edge test and bang on the playfield and see if the switch indicates closed.

If that's ok, the we'll get into the switch matrix...

Got your message.

There should be a test in diagnostics called switch test. It should have an 8 x 8 matrix showing if the switches are open or closed. So if you push the H, one of the indicators should come on. Play around with it, and use the manual, until you get the feel of it.

Then bang the table near the targets and see if the H switch indicates closed.

Also try pushing on the drop targets slightly. Not enough to make them drop, but enough to see if you get false switch indications.

Also visually make sure the drop targets are being full reset (pushed back up). I know there are some issues with that problem.

I know markmon has dealt with some of these issues, so hopefully he'll jump in here.

Do you hear it trying to push the targets back up? Mine had an issue where it was clicking 3x instead of 1x pushing them back up. I fiddled around with it but didn't find anything & just when I was about to call Stern it stopped doing it..