I bought a ZWO ASI120MM camera to use as a guide camera last month, to replace a previous guide camera that died after 14 years. I'm using it with MaxIm DL (v5.08), so I need to use the ASCOM interface to let MaxIm connect to it. I've been having lots of problem with this. The camera initially works fine with MaxIm when I initially connect to it, but then after a few images the camera starts returning the same frame over and over, regardless of what exposure I try to take.
Last night I downloaded the latest camera driver (v126.96.36.199) from the web site, and this seemed to work better at first. I was getting fresh image image data after each exposure for a couple of hours. Then, while it was running unattended the problem started again (around 10:30pm), ending up with many hours of bad exposures because apparently same guide frame was returned each time. Oddly, when my scope did a pier flip and took a full frame image to begin guiding again at 1:45am, the problem went away temporarily and I got another hour of good images, before the problem reoccurred and I lost the rest of the night.
I see in the forum here someone with a Nikon camera reporting the same symptom that I have, but overall this doesn't seem to be common a common problem.
I can tell that the camera itself is working fine because I downloaded PHD Guiding and tried it guiding with that software. I never had a failure when testing with that, but now that I know the problem can occur after a couple of hours I may not have tested with PHD long enough for it to show up there.
Do other people have problems using the ASCOM driver?