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Can a CMOS sensor be damaged by too much heat?

astrophotography CMOS equipment
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#1 bobequus

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Posted 14 February 2020 - 12:26 AM

The fan on my ASI183MC quit on me while I was working on my dark library.  The camera was almost too hot too touch and APT told me the sensor temp was 50C.  It may have actually gone higher than that.  I have no idea at this point how long it was at that temp.  I pulled the fan out and the red wire had broken its solder connection.  Tried fixing it, but they are just too tiny for my iron.  Went through my pile o' junk and found a 40mm x 10mm fan that would fit.  After some finegalling, I got it all back together and working.  The replacement fan is a bit faster and noisier than the stock fan, but APT showed it cooling to -15C with no problems.  I restarted my darks and looking at the first few, I see no obvious problems.  So the question is; was the sensor damaged in any way by the heat?  Can anyone suggest a method of testing to see if there is a problem?  My plan is to continue the project I am currently working on and shoot some exposures identical to one's I did before the mishap and compare the two.  Thanks for readin'!

Bobby



#2 coinboy1

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Posted 14 February 2020 - 12:36 AM

If the darks look the same and no obvious problems in the light frames I bet you are good to go. 50C = 122F so its not that hot.



#3 DSOs4Me

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Posted 14 February 2020 - 12:36 AM

ZWO says working temp is -5°C - 45°C ( 23F to 113F) so you were a little over but hopefully are OK if your darks and flats are fine.


Edited by DSOs4Me, 14 February 2020 - 01:25 AM.


#4 happylimpet

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Posted 14 February 2020 - 03:11 AM

I had EXACTLY the same thing happen with my ASI1600MM! And yeah, it was insanely hot to the touch. It seems absolutely fine. I too dont know how long it was like that....possibly hours.

 

I managed to solder the tiny red wire which was a b***ache, but I got there. Its done it twice actually and Ive soldered it, badly, twice.

 

I have since ordered a spare fan so next time it breaks I dont need to do that.

 

Like you I was worried about how hot it had got, but it seems fine! Ive done no quantitative tests but the darks seem the same, same bias level, my images look good, etc,


Edited by happylimpet, 14 February 2020 - 03:12 AM.


#5 RaulTheRat

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Posted 14 February 2020 - 03:15 AM

I had EXACTLY the same thing happen with my ASI1600MM! And yeah, it was insanely hot to the touch. It seems absolutely fine. I too dont know how long it was like that....possibly hours.

I managed to solder the tiny red wire which was a b***ache, but I got there. Its done it twice actually and Ive soldered it, badly, twice.

I have since ordered a spare fan so next time it breaks I dont need to do that.

Like you I was worried about how hot it had got, but it seems fine! Ive done no quantitative tests but the darks seem the same, same bias level, my images look good, etc,


That does indeed sound like a ballache. Do you happen to know the fan size and specifications or even a specific model number so I can keep a spare in stock?

#6 happylimpet

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Posted 14 February 2020 - 03:43 AM

That does indeed sound like a ballache. Do you happen to know the fan size and specifications or even a specific model number so I can keep a spare in stock?

There was a post in here recently showing one.....or maybe on facebook.... and ZWO will supply one for something like $10 I think, so that might be a decent option. As with everything theyre a delight to deal with.

 

I knew I could get one for more like £4 (sorry to mix currencies) so I shopped around. Also ZWO are shut down for the forseeable.... I will try to dig it out, but its written on the fan....


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#7 RaulTheRat

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Posted 14 February 2020 - 03:48 AM

There was a post in here recently showing one.....or maybe on facebook.... and ZWO will supply one for something like $10 I think, so that might be a decent option. As with everything theyre a delight to deal with.

I knew I could get one for more like £4 (sorry to mix currencies) so I shopped around. Also ZWO are shut down for the forseeable.... I will try to dig it out, but its written on the fan....


Thanks. Like you said, ZWO is probably a non-starter right now, hopefully they stay safe. The model number would be really helpful and I'll try to source one in Europe.

#8 happylimpet

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Posted 14 February 2020 - 03:51 AM

This was the replacement I bought...

 

https://www.ebay.co....872.m2749.l2649

 

I havent fitted it yet so be warned! But the part number is identical on the fan and the unit looks the same - it has a longer lead though, and I think it may have a 4 rather than 3pin connector, but sure it can be made to fit! I may have got this last but wrong though, i know some i looked at had the 4/3 pin thing).



#9 siriusandthepup

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Posted 14 February 2020 - 05:50 AM

Your computers cpu regularly runs up to 70 - 75 deg C. Doesn't hurt 'em.

 

Cooler is better for your electronic chip's lifetime, but you're well below any concerns at 50C.


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#10 bobequus

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Posted 14 February 2020 - 07:52 AM

I ran the camera overnight doing more darks.  I compared them this AM to previous darks from before the incident.  They look pretty much the same.  I also checked the darks that were taken during the meltdown.  The fan was off for about 11 hours.  APT reports the highest temp on dark taken during that period at 22C.  
As for the fan, it's a pretty common size: 40mm x 40mm x 10mm and commonly available on Amazon and Ebay.  However, ZWO uses a slower speed model that turns at around 5000RPM.  The one I replaced it with is a 7200RPM model and unlike the original fan, you can hear it and feel it (if you touch the camera). It does appear to make the cooler PS run a little less aggressively.  I have a Noctua low speed fan on order from Amazon.  I've used their fans before in my computers and they hold up well and push a lot of air with lower speeds and noise.

Bobby



#11 happylimpet

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Posted 14 February 2020 - 08:06 AM

I ran the camera overnight doing more darks.  I compared them this AM to previous darks from before the incident.  They look pretty much the same.  I also checked the darks that were taken during the meltdown.  The fan was off for about 11 hours.  APT reports the highest temp on dark taken during that period at 22C.  
As for the fan, it's a pretty common size: 40mm x 40mm x 10mm and commonly available on Amazon and Ebay.  However, ZWO uses a slower speed model that turns at around 5000RPM.  The one I replaced it with is a 7200RPM model and unlike the original fan, you can hear it and feel it (if you touch the camera). It does appear to make the cooler PS run a little less aggressively.  I have a Noctua low speed fan on order from Amazon.  I've used their fans before in my computers and they hold up well and push a lot of air with lower speeds and noise.

Bobby

The force applied by any imbalance in a spinning fan is proportional to the angular velocity squared, so going from 5000 to 7200 rpm will roughly double the amplitude of any vibration. Probably worth staying with a lower speed model, and Im sure the Noctua's are good. Broadly speaking, low noise ---> low vib.


Edited by happylimpet, 14 February 2020 - 09:22 AM.

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#12 luxo II

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Posted 17 February 2020 - 05:29 AM

CMOS chips withstand being soldered - at the silicon that’s 188C or 370F. - though obviously no power applied.


Edited by luxo II, 17 February 2020 - 05:40 AM.



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