Well my sander started running the belt off of it three weeks ago and I have replaced all the parts I would think would be needed and still no luck. It is an old pneumatic bridgewood 15". They no longer make them but the new grizzlies still are very similar and still use the same parts. I have downloaded a manual and made all the adjustments but nothing seems to work. I have a video of what it's doing. I don't think the top head is oscillating fast enough to turn the paper in time and it's hitting the cutoff switches and running off of it.
Here is what it is doing