Help - EFW2 has stopped working properly

[MicroAstro]

My EFW2, which has worked flawlessly for the past year, is now not working correctly. I changed a filter (I upgraded my SII to 3nm from 5nm, so all I changed was the SII filter in position 7) in the FW and reassembled, and now it is unable to precisely orient to the correct filter. When I plug it in, instead of automatically orienting to the L filter it stops more or less randomly at any filter. On the occasion when it correctly stops on the L filter, when I connect it to my control program it recognizes that it is on L, but when I ask it to move to another filter it usually just moves to the next filter (regardless of which one is selected) and the filter position in the filter wheel control just sticks on "Moving". I've adjusted the motor tension screw from loose to tight without effect. I've taken it apart and reassembled a dozen times. I've cleaned the FW edge where the detection holes are. I've checked that all of the holes are clear. Nothing has helped. I just seems to have lost the ability to move to the assigned filter either when it's first plugged in or when it is directed by the control program.

Any ideas what to try next, or is it time to send it back?
...Keith

[MicroAstro]

This is bizarre, but it seems to be the filter carousel that is causing the problem. I have an old carousel from when I first bought the wheel and the hole size tolerance was too tight for Astrodon filters. They remilled the carousels to have a slightly larger hole and sent me the replacement, which I have been using ever since. However, when I insert the old carousel the EFW2 functions flawlessly, setting on the 1st position (L) every time it is plugged in and my control program is able to move it to any filter without errors. When I put the new carousel back in I start having problems again. I've swapped them 5 or 6 times and always the same, works with the old carousel; no longer works with the new one. I can't see anything different about the two carousels, but the error is entirely repeatable.

Can anyone explain this and suggest what to do?
...Keith

[MicroAstro]

I may have it fixed, although I'm not sure. I cleaned the ring on the carousel that contains the orientation holes, and I touched up a couple of spots with flat black paint where the powder-coating was worn or chipped. I also made sure that there was no frayed rubber material from the outer band in any of the orientation holes. Anyway, the last 4 times I've plugged it in it has oriented correctly to filter position #1 (L) and my control program is moving the filters to the right position and no longer getting stuck on "Moving". I'd still be interested in why this might have fixed the problem or whether it has to do with the adjustments of the motor tension. Anyway, so far so good. I'll try it outdoors tonight at freezing temperatures to see if it works at observatory temperatures.
...Keith