qhy600 cooling

[kts12in1]

Hello Robin,
So far I am very happy with a QHY 600m, but I do have an intermittent problem with the cooling. Cooling down in small steps to -5 C things look good, but at, let's say -5C, the cooling starts to falter. Do I try to cool down to -10C cooling stops at, let's say at -7 or -6C.
Message I see is: Critical hardware error detected (VVLO event) Please check if input voltage is under 11 V. and correct it (code 3)

The QHY power supply delivers 12V- 6 amp. I am afraid this unit is unable to deliver enough amps. to cool the 24x36 mm sensor.
I contacted QHY before asking you for advice. Their message: Try another pwr.supply hmmm.( Maybe I need a 12V- 8/10 amps.) OR send in the cam to the nearest repair shop. I live in Western BC, Canada. Easier said than done.
Camera works fine at "normal" temp. (between room temp and 0 C.)
Maybe you have a more meaningful advise. My cam problem looks a bit unique, as I did not find anyone with the same problem.
( I am running Sharcap pro V 4. 91xx on 2 laptops )

Regards, William Devos

[admin]

Hi William,

the message about the Critical VVLO event error is coming direct from the QHY camera software (bypassing SharpCap). I think it probably is going to be related to the low voltage as mentioned in the error, but there are a couple of other things worth checking

* How heavy duty is the cable from the power supply to the camera? If it is lightweight then there could be voltage drop in the cable when the camera puts a high current load on the supply

* Is the plug which connects the power to the camera a good fit? A poor connection here could also lead to issues.

I've not seen cameras draw more than about 4A for cooling, but I don't have such a large sensor on any of the ones I have here, so maybe it will need more than 6A.

On a positive note, unlike older CCD sensors, newer CMOS cameras have much less thermal noise anyway, so it's no longer really critical to get as cold as possible. Holding a steady temperature of 0C or -5C is usually fine - keeping the same temperature is the key as it means that dark subtraction works optimally.
cheers,

Robin

[kts12in1]

Hello Robin,

Well, you and I are thinking in the same direction. The 600M. cam. works fine between the room temp and 0 C settings,
which is very reassuring to me, as you can imagine. !!
And yes, these new generation CMOS cams. are a different beast. Cooling down to -5 C. should do the job.
Those -15C/-20 C days are over, you know what I mean.
Oh, and by the way, I do have the same problem with QHY 410 (24x36 mm sensor.)
The warm summer nights here in BC are coming to an end and cool nights are ahead.!!
My next move is to try a different power supply (12V-10 amp.) unit and see what happens.
I suppose QHYCCD is delivering a good (top) quality pwr. supply with this pricy cam. however?!?!
The DC wire to the cam. looks oke.
So maybe draining 5-6 amp. cuts the voltage just under 11 V. This seems to be very critical.
Don't laugh at me now but maybe I need one power supply for the summer and one for the winter.
( Sharpcap Pro/ Phd2, what a joy to "play" with.)

Best regards, William.
p.s. I will keep you up to date !

[Jean-Francois]

Hello William,

For information ... I did yesterday some imaging with my WO-Megrez90 and my QHY-600.
Ambient ~ +15°C, cooling of the camera to -20°C ... and the current was around 2.7 A at ~95% cooling power (measured with my EAGLE and with 12.8V input power).

Regards,
Jean-Francois

[kts12in1]

Hello Jean- Francois,

That is good news. It is obvious that the power supply from QHY shows a voltage drop when it has to deliver a "few" amps.
I have a better quality (I hope) power supply on order. Maximum output 10 Amps. and I am sure there is no voltage drop when delivering just a few amps. to keep the camera cool.
My idea, don't cool the 600 cam. to -20 C. This camera is almost noise free at -5 C. It also extends the live of the sensor !!
Hot-cold cycles, hmmm....?
Clear skies !! William.