thinking of doing a DSLR cooling mod

[mindburner]

1358983043[/url'>' post='1797796']

I must get my Mk 3 version finished and see how that does.

For sure. I'd be interested in seeing your take on the sensor condensation issues. Some moddeds have tried to seal the sensor. Others using heaters.

I am waiting for bits for the Power supply system to arrive then I can test the camera outside, although I'm starting to forget how to do astronomy with all this bad weather about.

[Gina]

Sealed enclosure and silica gel bags is what I'm doing. I have too much else on ATM to work on it unfortunately.

[mindburner]

pretty gutted. dead camera. Pretty much finished too.

I think I send about 18v to the camera for a split second

will not power up now.

Re seated connectors etc - no joy:(

[Herbig]

I have a roll of un insulated nichromePM me if you want some. I've used this for dew heaters, I insulated it with the thinnest heat shrink I could find.

[Gina]

pretty gutted. dead camera. Pretty much finished too.

I think I send about 18v to the camera for a split second

will not power up now.

Re seated connectors etc - no joy:(

Oh dear My commiserations - I know the feeling

[mindburner]

yep, pretty sickening, especially as I pretty much got some success with the condensation

i'll maybe hunt on canon spares for a main board.

I think that is the most likely culprit

[mindburner]

found the issue.

I had shorted the common earth with 18v from a seperate PSU. The camera was plugged into USB wich acted as a virtual earth and created a circuit. The camera suffered the consequences

Here's an image of what looks like a track blown off the board. Not sure if the regulator? is ok or not, soldering would be very tricky

[mindburner]

managed to get a new motherboard and got the camera working again. The new board does seem to make the images noisier?! which is weird.

Got a few 3 min subs of M42 at -4 degrees EXIF (coldfinger -12)

some artifacts or something on the image but noise was not too bad. I will need a decent night without frequent cloud to get some decent testing done.

colour was difficult to process as I was using a custom white balance with the old motherboard. This was lost when swapped

[Gina]

Well done on getting you're cooling working As for those little strings of white dots, they're hot pixels. You get little trails of them as the images move slightly between frames so when stacked each hot pixel is in a slightly different place compared with the image. ie. as the frames are stacked the stars are aligned and the hot pixels come out in different places.

[Gina]

As for colour balance, I set mine for daylight and did any colour correction in software.

[mindburner]

Thanks Gina

Ahhh they are hot pixels. I was worried I had scratched the sensor or something.

I took the sensor assembly out again and cleaned it. I believe the surface is not actually the sensor but a glass cover, even with the filters removed.

I must say the resistor heater is great. Maybe lower values would be better than 47 ohm next time but the concept seems to work.

I'll try the daylight setting and see how it goes. I miss the rear panel also as a certain functions like auto power off can be a bit of a pain.

the power spike issue damaged my computers USB system. The pc now thinks there is a device present even when nothing is plugged in. If I disable this phantom device then it's ok

Cheers

Alan

[Gina]

You're right the surface behind the two filters is a glass plate glued onto the sensor frame. Unless you are playing around with cut diamonds you are unlikely to mark that glass cover.

Glad the heaters work, though I see you're getting quite a big temperature difference between cold finger and EXIF T reading. That is the trouble with heaters. But I can't say my method is perfect because I haven't perfected it

I'm pretty sure you can disable the auto power off from USB. I know I turned it off but not sure whether it was before I removed the backs or afterwards.