Pulled the SpaceCat out of storage last night to start a new build. But when I removed the tilter, I noticed that one of the pieces of film from the built-in camera rotator was sticking out of the end of the rotator inside the OTA. Same sort of situation as before. Apparently the repair service that the scope went in for didn't hold up.
The first time this issue occurred, I considered fixing it myself, but thought better of it and sent it back to William Optics in Taiwan. I don't know how the folks at William Optics repaired this, but their solution didn't seem to work. So I decided to fix it myself this time.
I think part of the issue may be that the film was adhered to the rotator collar instead of the inner wall of the OTA. I suggested this to William Optics prior to service, but they seemed unreceptive at the time. I don't know what the original intent was for those strips of film, but this is how I see them working.
When removing the retainer ring that held the rotator collar in place, I found a bunch of PTFE shavings in the threads of the retainer ring. The PTFE thrust washers looked like they were still in good shape, though. So I'm not sure where the shavings might have come from. I cleaned up all the shavings and removed the rotator collar only to find a single piece of film. When I took it apart before, there were three strips of film.
I cleaned and prepped the surface using 91% isopropyl alcohol. Then, using 3M 5480 PTFE skived film tape with silicone adhesive backing, I applied two strips of film tape to the inner wall of the OTA separated by about 120-deg from each other and the rotator clutch screw.
My reason for positioning the strips in this manner is that the strips of tape should serve as counter points to the clutch pin, and help keep the rotator collar centered in the OTA. Now to wait and see whether the strips of film will stay in place, or come loose yet again.
Comments
Post a Comment