My 15" Bridgewood open ended belt sander stopped oscillating this morning. The ceramic limiting arm had fallen off on the side with the pneumatic controls, and it's likely the errant belt created the problem. But I can't track it down.
The photos show the relevant parts. I am getting an airstream to the inside of that fork that the belt is supposed to periodically interrupt, prompting the oscillation cycle. But it doesn't oscillate. I can see that with the belt off, by turning the air on and off the tensioning cylinder is engaged, raising the top drum, and the oscillating cylinder sends the top drum rotating in one direction as the air enters, and it reverses that rotation as it deflates.
Left valve, attached to the cylinder that mechanically creates the oscillation, adjusts osciallation frequency, and the right valve the oscillation magnitude.
Oscillation has always been completely reliable since I bought the machine new, 25 or more years ago.
Bridgewood no longer exists. Most of the pneumatic parts seem to be the same or similar as in the current Powermatic (last pic), though they're assembled in different relative locations.
Can anyone describe next steps for troubleshooting, or likely part(s) to try replacing? This isn't the sort of thing I'm real adept at....
Thanks!