OK, so this is going to turn into something of a restore thread. Long story short, oscillation did not work when I got it. Information has been hard to come by on the web and I didn't think I could fix it and so planned to sell. However, I've been getting more information and find I can get the parts from Powermatic so I've decided to restore and make it part of my shop.
This was made in Taiwan which means I can't put information and restore thread on owwm.org so I'm posting what I can here to perhaps ask for help and advice, and to provide some information for anyone else with one of these guys.
First of all here is the user manual
. Powermatic has been helpful in providing this and other information. If you are taking this or other work on I recommend you call their customer service.
Here is my sander after cleaning up, but before restoring. (It was pretty filthy and the top had a bit of rust.)
So once I had the schematic I could be a bit more confident about cracking this baby open. Got the table and dust chute off, then the cover plate, and once I disconnected the switch wiring I could take out the motor and gear housing. Didn't take long to figure out the problem (or at least part of it).
Worm gear on the shaft totally stripped. Need to replace that and the wheel. It's a greasy, sawdusty mess under here as well. That'll need a good cleaning and relube. Here are more photos underneath.