ASI071MC-COOL Ice on sensor..

jinyoung

I purchased my ASI071MC-COOL last January from ZWO directly. Had fun couple of times but now I'm severely suffered from icing on sensor issue. I believe that it has been talked here several times.

It happens always when censor temperature reaches around 0 degree. I tried new desiccant (left it more than 24 hours) but it could not solve this problem. I also tried slow decreasing temp like 30 min to 5 degree, another 30 mins to -5 degree then -10 in 10 mins. But no luck.

I have FIT file (0.5 sec exposure at -15 and -10) from ASI071MC-COOL and photo taken by my phone:

https://drive.google.com/file/d/0BwoWeo6NkD6aNER6OXpHXzlXdzQ/view?usp=sharing

https://drive.google.com/file/d/0BwoWeo6NkD6aQkFaZEZLS0hSdHM/view?usp=sharing

How could I resolve this issue?

stellarskies

Jin,

Can you describe the environment you were operating the camera in? What was the humidity like? What was the temperature of the camera when cooling started? What was the ambient temperature when cooling started?

I have been using the cameras (have two ASI071's) many times over the past six months and never had the sensor ice up yet on either one. I cool them down to -5 or -10 depending on the ambient temperature over a 10 minute period. When I do this never does the power reach 100% draw (this is important!) and usually it settles around 40%-55% for the entire night (to maintain -5 to -10 set point), sometimes they can demand less power depending on the ambient temperature.

Here to help, just need more information on the environment you were in when this happened. :-)

jinyoung

Hi stellarskies,

Today's temperature during testing was around 25 degree Celsius. Humidity was between 50-60. I was at home during test. Note that I also saw this symptom at lower ambient temperature and humidity level.

Power level never reached or closed to 100% even I did down to -15 degree. I also tried down to 5 in 30 mins, then to 0 in 30 mins, then -5 in another 30 mins. It was fine until this point but when down to -10 in 30 mins again, then icing started again.

stellarskies

Well it seems somehow moisture entered the chamber and is stuck in there. We should wait for Sam to answer as that operating environment you described is well within tolerance and as you noted the power never reached 100% so it could not be due to over cooling either.

What I wonder is if you put the extra desiccant chamber on there for a day or two and then tried to cool it again would it not reappear. If it is moist air in the chamber that cannot escape this may eliminate it (for now) and then lets see if it reappears again later.

We will see what Master Wen has to say.

jinyoung

Unfortunately, I already tried new desiccant few days ago. :(

I'm thinking about opening chamber and cleaning sensor protect window by cleaning kit (I have DSLR sensor cleaning kit already) but have little fear about opening chamber and don't know how to.

Well, would try another desiccant again.

stellarskies

Jin,

You may be right, since it has iced over a few times now the sensor may need cleaned. It is kind of like dew forming on optics, once it does it once there is a surface established for it to happen again. What is so odd is that you are not cooling it irrationally and this is happening.

Sam I am sure will know what is best but I think you are right, you may have to clean the sensor. It is not hard, done it many times with DSLRs, just get a good sensor cleaning kit and take your time and you will be fine. :)

Sam@ZWO

please put the desiccant tablets into microwave oven for 2 mins

and then use it

please also check the air socket screw, seems this screw on our first batch 071 is too long and cause the camera is not sealed

we can send you the short one if your camera use the long one

jinyoung

Sam wrote:
please put the desiccant tablets into microwave oven for 2 mins

and then use it

please also check the air socket screw, seems this screw on our first batch 071 is too long and cause the camera is not sealed

we can send you the short one if your camera use the long one

Thanks Sam, I'll try microwave oven way. BTW, how can I check mine is long one or not? I'm willing to pay necessary fees if I need it.

Sam@ZWO

Jinyoung wrote:
Sam wrote:please put the desiccant tablets into microwave oven for 2 mins

and then use it

please also check the air socket screw, seems this screw on our first batch 071 is too long and cause the camera is not sealed

we can send you the short one if your camera use the long one

Thanks Sam, I'll try microwave oven way. BTW, how can I check mine is long one or not? I'm willing to pay necessary fees if I need it.

the long screw can touch the heater board, you can tell from the mark of the heater board

you can send email to us, we can send it to you free

javrolijk

Sam wrote:
Jinyoung wrote:
Sam wrote:please put the desiccant tablets into microwave oven for 2 mins

and then use it

please also check the air socket screw, seems this screw on our first batch 071 is too long and cause the camera is not sealed

we can send you the short one if your camera use the long one

Thanks Sam, I'll try microwave oven way. BTW, how can I check mine is long one or not? I'm willing to pay necessary fees if I need it.

the long screw can touch the heater board, you can tell from the mark of the heater board

you can send email to us, we can send it to you free

Dear Sam,

When is the second batch of 071 coming out with the corrected screw lenght?

Kinds regards,

Jairo

Sam@ZWO

we are going to release ASI071 Pro soon

which has better design and has 256M DDR buffer