My ST8XE CCD sensor chip keeps frosting up even after changing out the reusable desiccant packs twice and changing out the desiccant plugs after they were recharged by letting them bake in my oven for four hours at the recommended temperature. What would cause the camera cooling system to malfunction like that?
Check the O-ring on the desiccant plug. You're supposed to remove it from the plug before baking, and put it back on afterwards. If you didn't remove it, it might be damaged and not sealing properly.
If you need to replace the desiccant, the Optical Structures / Farpoint people have made a replacement plug that fits. We don't have the originals anymore, but the Farpoint unit seems to work fine. https://farpointastro.com/shop/sbig-camera-replacement-desiccant-plug/
I have that one and it didn't either. Also, that one did have an O-ring. Also, it was working fine before. I had the temperature down to -10°C before and had no problems. I originally thought it needed a new desiccant pack and I changed it out twice.
It's $9.34 for 100 O-rings from McMaster Carr. https://www.mcmaster.com/9557K465/ Massive overkill in terms of having extra O-rings, but perhaps the least expensive option.
O-ring from Ace Hardware. https://www.acehardware.com/departments/plumbing/faucet-and-faucet-repair/o-rings/4011953 I had to recharge the dessicant plug in my ST-2000 twice last week before it stopped the condensation. It worked the other night at the DSS. Joe
Good point, Joe. If the chamber is very wet it might take a couple of recharges to clear out the water.
