I ended up doing what 62 max did. I drilled out broken screw part. Then enlarged it to 1/4" (used slight undersize ream from McMaster Carr. Inserted 1/4 aluminum rod about 1/2" if I recall. drilled and tapped for new screw. I ended up having to do all four. I had one that was ever so slightly off center, but didn't seem to affect performance. At least as good as I had the tune I could get.