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Troy, I have had a couple of issues with dewing up - first on the front filter. The camera came with a heater ring to attach to the front t-threads however I found the heater tended to be warm on the side that connected to the flattener rather than the side attached to the camera so it didn't prevent the front filter dewing up. I build a heater ring out of resistors that fits around the 2" nosepiece on the front of the camera and haven't had this problem since.
The more recent issue I've seen is moisture forming on the CCD itself. I've tried drying the camera in dessicant however this was limited in its success. After discussing the problem with Theo he suggested cleaning the CCD surface with Acetone followed by purging the sealed chmaber with Argon. I have purchased a couple of cylinders of argon and performed this routine a number of times now It works for a while however it seems that moisture makes its way back in over time.
There seems to be three possible leak paths - 1. where the electronics from the CCD pass through the back of the sealed chamber, 2. the screwed connection where the nosepiece attaches to the body and 3. around the front filter. I notice the newer versions of the QHY cameras come with a port in the chamber to attach a dessicant plug. I assume this feature was incorporated to address moisture getting into the sealed chamber.
I've sent the camera back to Theo and he has checked the seal at the rear of the chamber and around the front filter so it appears the leak is in the threads where the nosepiece attaches to the camera body. I've raised a ticket on the QHY help system and they recommend putting vaseline in the threads to help seal the chamber. This process is going to get very messy as it will all need to be done inside an argon filled plastic bag if I want the chamber to remain dry (there is no point sealing moisture inside the chamber).
I've asked Theo if he could get a new nosepiece for the camera with the dessicant port as this would reduce the need to open the front of the camera up and allow use of a dessicant plug. He is looking into it.
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