[RyanJones]

Hi All,

I thought I'd start up a new thread rather than dragging out my old thread on my cooling project because I've created a monster problem and I need some advice.

I have been waiting for a better heatsink and a thermostat to arrive for my DSLR Peltier cooling project and they did last week so the weekend was time to finish construction and do some testing. The Cold finger worked better than I ever thought it would being able to maintain a stable temp of 0 Degrees in a 20 Degree ambient room. After a bit of fiddling I set it to 3 Degrees and started taking darks to look at the noise. This is where the problems began......

The plan was to take 10 darks @ 3 Degrees then 10 @ ambient and compare them. 8 subs in and the camera froze. I don't mean icy, it became unresponsive, not even to the on/off switch ( and it was on ! ) so I removed the power and let it warm up for a few minutes. It fired back up and started working again so I left it for 1/2hr or so to get to true ambient. Figuring I'd just gone too cold with the finger, I set about taking my ambient darks. 10 subs in and no problems......but....... I then went to take a normal image and I got Err 99 on the camera. I'll save you the investigation but essentially at some point my shutter has jammed/become unresponsive. More fiddling etc. etc. I figure I've killed the camera. Upsetting to say the least but I have another Identical camera so I just have to spectrum modify it and ill be back in business. But then I looked at the darks.......

Below are 2 x 100% crops of my darks. First is with the cooler on, 2nd with it off ! What the hell ????? A screen full of Blue hot pixels ? Clearly I've caused this with the finger but how ? The second ambient sub shows my fairly normal noise pattern although there is a significant pattern of blue hot pixels in the full image ( not pictured ) coming from the bottom of the sensor that diminished the more ambient subs I took. This one being the best of the set.

As I said, I'm not happy that I've killed a camera but I do have a solution but I don't want to pull the new camera apart twice so I need to know what the likely cause of this issue is so I can either rectify it and fit the cooler or not fit it at all.

Any help is greatly appreciated.

Cheers

Ryan