Atik 460m Cooler Problem

[nightster]

This has been posted in the Atik's forum but from the looks of things there they get almost no replies.

This problem first popped up last Saturday night. I couldn't get the CCD to cool below 7c then. I did some powerdowns and it began working. Cooled to -5 as I normally have it set. Today I'm running it on the bench to debug this issue. I'm using a regulated powersupply at 13.8v to power CCD. I've used several different USB cables and 2 different power cables. There is no problem connecting to the camera and the cooling power percentage changes when setpoint is changed. All seems to be working, the camera takes images and downloads them.  I've used APT and SGP and run the cooler today and from the ASCOM driver also. Trace on is ON and there is no errors in log, but that is avail if needed.  The only issue is that is can't seem to get full cooling.  Last weekend the ambient was about 18c and the lowest it would go was about 7c.  Indoors today it is about 23c and the lowest it will report CCD temp is 16.6c.  Last weekend I was running the original drivers that came with the cam, today I updated them from Atik's download page.  I don't like the smell of this problem...   I haven't read that the Peltier coolers are failing on these Atiks.  I'm still hoping something got twisted somewhere.  3 weeks ago the camera had been flawless for the 3 years I've had it.

[symmetal]

Is the fan working and moving air? No sign of any blockage in the airflow. After three years some dust may have accumulated on the peltier heatsink. It looks like the rear panel comes off if you undo a couple of screws. A peek inside might help.

Have you always powered it off a 13.8V supply? The 25 degree delta cooling figure is when it's powered from 12V. When operating from a higher voltage the cooling effect will be reduced as the peltier device has to first dissipate the extra heat (about 1.6W) produced by the higher voltage before it can start cooling the camera. I would still expect it to be better than the 10 degrees or so you're getting at the moment.

Alan 

[kirkster501]

I have had a similar problem to this.  Leave SGP aside (that uses the AScom driver)  and just do this from Artemis that uses the direct driver.  Does it work then?

[ollypenrice]

3 hours ago, kirkster501 said:

I have had a similar problem to this.  Leave SGP aside (that uses the AScom driver)  and just do this from Artemis that uses the direct driver.  Does it work then?

Good advice. When somethng isn't working, run it in its own software. It must be more than ten years ago that I heard this from Ian King but it's good advice today.

Olly

[kirkster501]

I had to update the Atik drivers to the latest versions.

When I had these issues sometimes if I cooled the Atik with Artemis to get the temperature down to -20 then switched to SGP or APT it would maintain that lower temperature that was achieved by Artemis.  However, SGP or APT (using the ASCOM driver) could not by themselves get the temperature low enough.  It was really weird and intermittent.  This was a bug in the ASCOM driver that was reporting the temperature back incorrectly.

[nightster]

I'm working with Atik now. Intake ports are clear. The cables are good. The power supply is within spec. Using Artemis I get a Tdelta of 7C and the same with the ASCOM driver. It is only drawing .34 amps. That is what Atik asked me to check. It should draw near 1 amp at 100% power.  The camera works, it connects, is takes images, downloads the data, etc. It just isn't cooling more that about 7-8C.  So now I wait for the response. I'll let you know. I haven't read about any cooler behaving like this. Usually its all or nothing with solid state equipment.

[nightster]

Atik says hardware failure. Needs to go back. I'm out of the imaging business for October, at least.  

[kirkster501]

Is the camera out of warranty? May I ask how much it costs to repair?

Time to get some visual astronomy under your belt then.

[nightster]

Yes out of warranty. I've had it 2.5 years. Right now I've got 100 US$ in shipping it to Atik. I didnt mess around with cheapest shipping mode, it should be there in 3 days.. After that it's a wait and see. They did say a peltier is 75US$ which isn't bad. Hoping that's all it is. Not sure if they charge for a cleaning or tune up or recharging the sensor compartment. Gonna let them do what needs to be done.

[Adam J]

One of the things that can cause that kind of failure is thermal shock to the TEC. Hence why setting the cool down period of a good 10 mins is advisable. Mind you that's not the only possible cause so.

[ollypenrice]

On 27/09/2017 at 15:01, Adam J said:

One of the things that can cause that kind of failure is thermal shock to the TEC. Hence why setting the cool down period of a good 10 mins is advisable. Mind you that's not the only possible cause so.

On the two stage Peltiers I'd agree, but on the cylindirical Atiks the cooler is not very powerful. (Not quite powerful enough, some might say.) I'd be surprised if this were from thermal shock. Probably just a random component failure.

Olly

[nightster]

I've always used the the 10 minute cool down and the 10 minute warm up. But there have been a few power drops or a spontaneous laptop reboots that have cause a sudden loss in cooling. But just a handful of times. I treat my Atik like a mother with her newborn baby.  Craddled and swaddled in foam and desiccant packs. 

[kirkster501]

I may move my cooling/warm up to ten minutes too.

Hope you get it sorted OP.  Let us know how much it costs to put right a we love the 460 very much.  Atik are renowned for after sales support.

[Adam J]

On ‎28‎/‎09‎/‎2017 at 17:06, ollypenrice said:

On the two stage Peltiers I'd agree, but on the cylindirical Atiks the cooler is not very powerful. (Not quite powerful enough, some might say.) I'd be surprised if this were from thermal shock. Probably just a random component failure.

Olly

Ah never thought about that, does make sense that the stress would be less given their lower than standard cooling performance.

[nightster]

Well I'm not sure that 'lower than standard' is warranted. It really is a clean sensor. Attached is a dark from this cam. I only ran the CCD at -5. Which for the hot southern part of the US is obtainable at least for 3 of the 4 season. And honestly with bugs, humidity, and short nights I can live without imaging in the summer. 

 

 

[ollypenrice]

18 minutes ago, nightster said:

Well I'm not sure that 'lower than standard' is warranted. It really is a clean sensor. Attached is a dark from this cam. I only ran the CCD at -5. Which for the hot southern part of the US is obtainable at least for 3 of the 4 season. And honestly with bugs, humidity, and short nights I can live without imaging in the summer. 

 

 

As someone who loves the Milky Way and runs an astro holiday business I can't live without imaging in the summer! I've found the cooler just about suffices in SE France, at altitude, but I've discovered that there is more to noise than clean darks. The strange thing is that I have more noise problems from my Sony chipped 460 than from my Kodak chipped full frame CCDs once it comes to processing stacked images. The noise from the Sony takes the form of irregular signal in the background sky. Not hot or bright pixels but the opposite, pixels which haven't pulled in enough signal and are unduly dark.

I would like to see another 10 degrees cooling from my 460, to be honest, but it does work year round from my location. My night time temps are rarely above 20C.

Olly

[nightster]

@ollypenrice Point taken. You have much different parameters than I do. The family likes to do things during the summer weekends so my summer hiatus allows that to happen more often. This is an interesting point I've not read about before, the irregular background signal. I'm going to start looking for that when I get my camera back.  

Has anyone tried to modify their CCD with a higher performing peltier? Does it take a 2 stage system to go below a certain point? 

[Adam J]

2 hours ago, nightster said:

@ollypenrice Point taken. You have much different parameters than I do. The family likes to do things during the summer weekends so my summer hiatus allows that to happen more often. This is an interesting point I've not read about before, the irregular background signal. I'm going to start looking for that when I get my camera back.  

Has anyone tried to modify their CCD with a higher performing peltier? Does it take a 2 stage system to go below a certain point? 

No not as such. I get 23c below ambient from my DSLR cooler, but that is water cooled and the actually cold side of the TEC (peltier) is much much colder than 23 below ambient, that is because I can remove lots of energy with the water block and the water itself is colder than the ambient air temperature. Meaning that its more the differential between the water temperature and the cold side temperature that matters as oppose to the ambient temperature. Some pro setups use water cooling (such as SBIG cameras for this reason).

The actual problem is one of efficiency, the ability to keep the warm side of the TEC cool. TECs have a maximum temperature differential of about 60c to 70c between the hot and cold sides but the higher the temperature differential the lower the efficiency with which they pump heat meaning that they reach a state of dynamic equilibrium at a much lower temperature than their theoretical maximum temperature differential.  So while it is possible to go lower with a single TEC, you would need a higher power one so that it could pump more energy at a given temperature differential / efficiency...problem is that requires more power and a much larger cold side cooler (normally a heat sink and fan) so in the end it all weighs to much.

The way around that is to step down the temperature by cooling the warm side of the 1st TEC with the cold side of the second, hence dividing the temperature differential across two TEC as opposed to one and increasing the maximum temperature differential. This can be made to work even better if the TEC in contact with the CCD is smaller than the second one which is in contact with the heat sink and fan.

I seriously doubt that you could fit a double TEC into the atik and if you could I would be worried about power handling / blowing the temperature regulator due to excessive power draw.

Hope that helps.

[nightster]

Update: It took 2 days to ship the CCD from North Carolina to Atik. They had the problem identified within a week of its arrival. The peltier was in fact failing. They quoted the repairs. I asked if any addition service should be done while it is there (sensor cleaning, etc..) They said all that would be included in the quote.  I approved the same day. They accepted paypal, which for the small cost of this repair was cheaper than a bank to bank transfer. Two days later they reported the CCD repaired. I had a few questions about the Camera: Voltage limits, need for new calibration frames, using only Bias wo/ darks, and cool/warm down times.  They said Vmax is 13.8, yes shoot new calib frames, you can sometimes get away without Bias but for best results use Bias and Darks, a 10 minute cool down is preferred , and finally warm up is built into camera which is triggered by software. An hour after that answer, another came with a UPS tracking number confirming shipment has begun. 

 

I opened this support ticket on Sep 25, with the camera in my hand.  11 days later the CCD has been repaired and is on its way back to N. Carolina.   I have no idea how ATIK could have any better customer service. I am absolutely thrilled that I took the advice on many on this Forum and choose ATIk. For 8% of the NIB purchase price I will have my camera back before the next new moon and will have missed only a single night of imaging that was planned on Sep 23rd, when I first suspected it wasn't working properly.  The communication level was excellent, even with the US/UK time zone differences. I'd send an message in the evening and a response would be waiting for me when I woke up.  The speed of diagnosis and repair were just a few days.

I can't say enough them, what a great company.  To Atik: thanks for offering up what I consider the best value in dedicated Astro cams with world class after sale service and support.

[kirkster501]

What a great outcome for you and a what a great company.  A CCD is a considerable investment for all of us and it's gratifying to know that Atik looked after you.

All the best, Steve

[Adam J]

Its great to know that you got good service from them, those things make a big difference in choice of manufacturer. 

[nightster]

Couple of hours on the bench for Bias and dark and it's performing well. When I get a master I'll compare the before and after cooler fail as I did a batch of dark back in the summer.