Issue with ZWO ASI071MC pro cooling

[msacco]

Hello, I'm having an issue with my ASI071MC pro. I've been struggling with this for a while now, and came up with the following conclusions:
Somehow when the cooling of the camera reaches high TEC(90-100%), it causes the camera to crash. I know it sounds weird, but I'll try explaining as much as I can.

The reason I believe is not a software issue, is that I've had the same results on 2 different machines, on 2 different OS(one running W7 and the other W10), on 3 different programs(ASICAP, SharpCap, SGP) - I had the exact same results on both. The issue also happened when the cooling reached high TEC(around 90-100%), I tried running the cooling for very very long on low power, and everything still worked just fine, only when I rose the power to around 100%, the issue appeared.

What actually happens when the issue occurs?
On SGP, if I'm taking frames once it happens it's simply stuck on downloading the frame, until eventually after really really long I believe it will say that it wasn't able to download the frame.

On SharpCap it simply drops the frame and keeps capturing, that is until I click on the 'Cameras' menu, and then it simply "throws" my camera and disconnects it.
I tried to contact ZWO, still waiting for their reply, I also didn't found anything related to that anywhere, so I guess I'm the first one with the issue.

Some technical details:
I've tried using different cables, both USB2/3.
I tried different power supply, mainly with 12V 5A one which should be more than enough.
I tried 2 machines as I stated above.

One more thing that happened to me, I tried using the camera in the field with my 12V 75AH battery, I don't know it for sure, but I believe that once the cooler reached high TEC of 90-100%, my 5A fuse got burned, which is extremely weired as the camera should only draw 3A max(even with slightly more). This thing happened to me 3 times, so I believe there's something wrong there.

Here is a(very very very poor) video of me showing how sharpcap starts dropping frames when the TEC rises:
https://drive.google.com/file/d/1PWKP2ARaL7CapfPqw91SJmiLn5g2qYV0/view

Any ideas would be much appreciated! Thanks!

[Adam J]

I would think that this is a case of insufficient current being supplied drawing down the voltage. Try a volt meter to measure the volts being supplied as the cooler maxes out. It's not a great idea to be running at max delta anyhow. 

[msacco]

4 hours ago, Adam J said:

I would think that this is a case of insufficient current being supplied drawing down the voltage. Try a volt meter to measure the volts being supplied as the cooler maxes out. It's not a great idea to be running at max delta anyhow. 

As far as I know it's not something that could happen with 220V AC, but only in 12V DC which caused the fuse to burn.

[Thalestris24]

What's your ambient night time temperature?

[msacco]

12 hours ago, Thalestris24 said:

What's your ambient night time temperature?

I was in my room, so probably around 20-30C. But I don't think it should be related in any way..It doesn't matter what temperature the camera is trying to reach, it should still be able to run at 100% TEC. Whether it actually manages to cool down or not is a different story, but I don't think it should be related?

[Thalestris24]

2 hours ago, msacco said:

I was in my room, so probably around 20-30C. But I don't think it should be related in any way..It doesn't matter what temperature the camera is trying to reach, it should still be able to run at 100% TEC. Whether it actually manages to cool down or not is a different story, but I don't think it should be related?

I think most modern tecs have a delta of 40 deg. So at 30 deg you should be able to reach -10 deg. Therefore you shouldn't set your target to lower. The camera should be able to reach -10 but it will draw a max current. There may also be a maximum ambient operating temperature and humidity specified by the manufacturer. If you're unhappy with the camera you could ask the seller for a refund.

Louise

[Thalestris24]

Spec for the pro version is here https://www.firstlightoptics.com/zwo-cameras/zwo-asi071mc-pro-usb-30-cooled-colour-camera.html#specifications

[Guest]

Are you using any USB HUB ?? 

[msacco]

6 hours ago, Thalestris24 said:

I think most modern tecs have a delta of 40 deg. So at 30 deg you should be able to reach -10 deg. Therefore you shouldn't set your target to lower. The camera should be able to reach -10 but it will draw a max current. There may also be a maximum ambient operating temperature and humidity specified by the manufacturer. If you're unhappy with the camera you could ask the seller for a refund.

Louise

But once again, it doesn't matter if the camera is able to reach temperature x or not, it should still be able to run at 100% TEC without any issues, whether it managed to reach the temperature I've set it to or not.

4 hours ago, artem said:

Are you using any USB HUB ?? 

No, I'm not using a USB hub.

[Thalestris24]

11 minutes ago, msacco said:

But once again, it doesn't matter if the camera is able to reach temperature x or not, it should still be able to run at 100% TEC without any issues, whether it managed to reach the temperature I've set it to or not.

No, I'm not using a USB hub.

I just read your posts on CN and see you bought it second hand. Reiterating the relevant specs:

Cooling: Regulated Two Stage TEC
Delta T: 35°C-40°C below ambient
Cooler Power consumption: 12V at 3A Max
Working Temperature: -5°C—45°C
Storage Temperature: -20°C—60°C
Working Relative Humidity: 20%—80%
Storage Relative Humidity: 20%—95%

You may be using the camera within spec but things can age and deteriorate. Under those circumstances you need to contact ASI and see about getting it serviced if it won't cool down to a delta of 35 deg. Only the surface of the TEC in contact with the sensor should get cold. The rest of the hardware - heatsink and fan, does it's best to take heat away from the 'hot' side of the TEC device. How well it does this depends on a number of factors. Personally, I wouldn't, and never have, attempted to run a cooled camera at 100% power. TEC devices are semiconductors and can quite easily fail under certain conditions.

Louise

 

[Thalestris24]

From jdupton on CN:

" The reason I suggest cooling to at least around 15 degrees below ambient is to operate the TEC in an easily controlled zone in order to attain temperature stability. When the TEC is operating at less than about 5% of its power level capability, the stability of the sensor temperature will usually be less controlled compared to when the TEC is operating at about 30% power level. Conversely, then the TEC is operating above 80% power, self heating of the sensor by the camera body can start to affect temperature stability.

 

   I have recently run tests of this on my ASI294MC camera. I found that as the TEC approached 90% to 100% of power, the actual temperature of the sensor started rising due to excess heat from the TEC being dumped into the body of the camera. That in turn, raised the temperature of the sensor and reduced the stability of the temperature since the TEC is cooling the back of the sensor and the circuit boards to which the sensor is attached are warming the sensor. In my camera, this leads to an instability of the actual sensor temperature over the period of an imaging session.*

[msacco]

5 hours ago, Thalestris24 said:

I just read your posts on CN and see you bought it second hand. Reiterating the relevant specs:

Cooling: Regulated Two Stage TEC
Delta T: 35°C-40°C below ambient
Cooler Power consumption: 12V at 3A Max
Working Temperature: -5°C—45°C
Storage Temperature: -20°C—60°C
Working Relative Humidity: 20%—80%
Storage Relative Humidity: 20%—95%

You may be using the camera within spec but things can age and deteriorate. Under those circumstances you need to contact ASI and see about getting it serviced if it won't cool down to a delta of 35 deg. Only the surface of the TEC in contact with the sensor should get cold. The rest of the hardware - heatsink and fan, does it's best to take heat away from the 'hot' side of the TEC device. How well it does this depends on a number of factors. Personally, I wouldn't, and never have, attempted to run a cooled camera at 100% power. TEC devices are semiconductors and can quite easily fail under certain conditions.

Louise

 

 

2 hours ago, Thalestris24 said:

From jdupton on CN:

" The reason I suggest cooling to at least around 15 degrees below ambient is to operate the TEC in an easily controlled zone in order to attain temperature stability. When the TEC is operating at less than about 5% of its power level capability, the stability of the sensor temperature will usually be less controlled compared to when the TEC is operating at about 30% power level. Conversely, then the TEC is operating above 80% power, self heating of the sensor by the camera body can start to affect temperature stability.

 

   I have recently run tests of this on my ASI294MC camera. I found that as the TEC approached 90% to 100% of power, the actual temperature of the sensor started rising due to excess heat from the TEC being dumped into the body of the camera. That in turn, raised the temperature of the sensor and reduced the stability of the temperature since the TEC is cooling the back of the sensor and the circuit boards to which the sensor is attached are warming the sensor. In my camera, this leads to an instability of the actual sensor temperature over the period of an imaging session.*

Thanks for the comment, I do trust the seller, he said that he only used it about 3 times and after few uses of mine it already looked more used than what I recieved it, so I believe the camera supposed to work well.

He also got the camera from Sam because he helped translate the manual.

That doesn't mean it's not possible that the camera is faulty.

I'm aware of the fact that cooling at 100% is not recommended or even useful at all, yet I would love to understand where the issue is coming from.

ZWO told me they'd want to have a teamviewer session and see the issue, would make sense to me that they would simply tell me to send it to repair, but I don't know what will happen with shipping..

[Thalestris24]

As above, as the cooler gets to >90% it loses efficiency. As long as it achieves the 35 deg delta it is within spec and there is no fault.

Louise

[msacco]

33 minutes ago, Thalestris24 said:

As above, as the cooler gets to >90% it loses efficiency. As long as it achieves the 35 deg delta it is within spec and there is no fault.

Louise

Crashing the camera at 100% TEC doesn't sounds like within the specs to me 😁

[Thalestris24]

Just now, msacco said:

Crashing the camera at 100% TEC doesn't sounds like within the specs to me 😁

The specs don't claim the tec will work reliably at 100% - as above, operation becomes unstable >90%. The spec only claims a delta of 35-40 deg below ambient within the given environmental limits.

Louise

[msacco]

9 hours ago, Thalestris24 said:

The specs don't claim the tec will work reliably at 100% - as above, operation becomes unstable >90%. The spec only claims a delta of 35-40 deg below ambient within the given environmental limits.

Louise

Well I would expect ZWO to think about such situations when making a product. It's like making a computer with 5 GHz specs, but when the computer reaches that it crashes(BTW it's not far from the latest MAC at 4.8 GHz haha).

If the camera can't handle 100% TEC, then don't let the camera reach 100% TEC no matter what.

[Adam J]

The thing I would note here is that QHY would see to have a better reliability record with the larger sensors than ZWO, there is a new full frame coming out from both makes, I would be considering the QHY if it was me irrespective of it costing more. 

[msacco]

Just now, Adam J said:

The thing I would note here is that QHY would see to have a better reliability record with the larger sensors than ZWO, there is a new full frame coming out from both makes, I would be considering the QHY if it was me irrespective of it costing more. 

Well I just bought this camera recently, so getting a new camera is completely out of the question. 😕

[Adam J]

9 minutes ago, msacco said:

Well I just bought this camera recently, so getting a new camera is completely out of the question. 😕

It was more of a comment than a suggestion. 

[msacco]

1 minute ago, Adam J said:

It was more of a comment than a suggestion. 

I've actually never saw many issues with ZWO products, I'm also in contact with their support and they're trying to help me with solving this issue. Hopefully everything will work out eventually.

[Adam J]

9 minutes ago, msacco said:

I've actually never saw many issues with ZWO products, I'm also in contact with their support and they're trying to help me with solving this issue. Hopefully everything will work out eventually.

Its specifically that model, hope you get it working. 

[msacco]

1 minute ago, Adam J said:

Its specifically that model, hope you get it working. 

Interesting...Thanks!