STX Guider Shutter

I have an STX 16803 with FW7-STX filter wheel and STX Guider. At some point a while ago I stopped seeing guide stars. Since I do a lot of unguided work I chalked it up to there just being no guide stars on the chip but as it happened more and more I got suspicious. No luck after moving the pick off mirror in and out and playing with focus. The last time I had the camera off I took the guider off to get a sense of what was going on inside. The mirror seems like it is in a good spot and I can verify that the sensor is working as it picks up ambient light proportional to how much light is in the room. I do notice that the shutter controlled by a little DC motor does not move when I do an exposure. I can move the shutter manually and see that there is a major difference in the amount of light hitting the chip. When I put a voltmeter on the motor leads the meter shows a bump to 0.35 V when the shutter should be open. The pulse could be too fast for the meter to measure properly so I wouldn't put much stock in the 0.35V number but there is some voltage to the motor. Any thoughts about, well, anything would be appreciated.

P.S. I also notice that the (unrelated) terrible sound the big chip shutter is making seems to be related to the shutter stuttering across as it opens and closes. Maybe it is just time to send both units in? I am reasonably handy with mechanical things and electronics so if I can save on downtime that would be good too.

Cheers,

Bill