Temperature regulation with DL6 and STT8300M

Hi
Maxim DL6 and STT8300M has recently stopped properly controlling the temperature. It has work flawlessly the last 3+ years. I always use -25C and power normally 80-90% at 20C ambient.
Currently ambient is 27C (indoor):

Camera connects okay. I tried these temps in order shown...
Set temp to -10C. After 15 minutes temp at -10.3 and power at 0 to 1%.
Set temp to -20C. After 1o minutes temp still at 11.7C and power at 100%
Set temp to -11C. After 15 minutes temp at 11.7, power at 0 to 1%
Set temp to -7C. After 1o minutes temp at -7C , power at 1 to 2%.
--- Is it possible to cool from 27C ambient to -7C with 1-2%?
Set temp to 0C. After 10 minutes -5C, power at 0 to 1%
Set temp to +10C, After 10 minutes 10C, power 0 to 1%
Set temp to +5C. After 10 minutes temp 4.9, power 0 to 1%
Set temp to -12C. Power goes to 100% and temp dropped to -1.2, then gradually goes up to .4C. I turn it off. Power was still at 100%.​

IMO, the sensor seems to cool down faster than usual, overshoots, then takes longer than usual to stabilize.
Also the power levels seem very low if above -7C.
System loses control sometime if below 0C.

Windows 10.
MaximDL6.16
Stt8300M with Self Guiding Filter wheel and AO8T.

Any additional information I can provide?

Thanks,
Roger

 

Thanks Doug. Your advice and experience is always valued. Will check using CCD Ops and also follow in the STT section. Roger

 

More evaluation...
Today I used CCD Ops and checked temperature and power at several temps down to -25C. All seems okay. All this done in my home.
Then did same with Dl6. All seems okay.
Then with -25C setpoint and temperature stable I started running 50 flats at 2.6sec each. Power is about 2%.
At the 23rd flat the camera shutter blocked part of the image. Temperature stable on 24th image.
On 25th image the temp increased to -21.7C (fits header), and continued to increase on following images. Power (and fan speed) went up to 100%.
At 30th image the temperature was -9.4C. Power 100%. I stopped imaging at 31st image. Camera reported still connected. Warm up did not reduce power. Disconnect camera from DL6 and reconnect still would not control the camera power.
Unplug camera.
This is the same loss of temperature control I described above. No cables were moved. No red LED on the camera indicating low voltage (even at 100%).
Kindly advise what I should be checking.
Thanks,
Roger

 

Hi Doug,
1. Serial T13010325 STT8300M
2. Driver Checker updated 1 driver on computer, and 1 firmware file on camera uploaded. Then reboot camera.
3. Logging zipped file attached. I repeated the experiments, but did not wait for complete temp settling.
Power and temperatures behaved same as before. Basically running at 0-2% at -25C. Room temp is 26C.
Fan speeds up when power goes above 50% (like when change the temp colder). Below 50%, fan slower.
I know the camera is cold since I have frost showing in my flats. Time to dry the desiccant.
I could not duplicate the problem where the power went to 100% (after change to colder temp), but the temp went up, not down.
4. Yes, very slow when logging.... Now how to turn off the logging?
5. I could not duplicate the images with the shutter partly stuck across the image taking 2.6 sec flats. (Everything was slow while logging so only a few images taken today). Any comment on the shutter?
Thanks for reviewing and your advice.
Roger

 

Hi Adam and Doug,
I appreciate you gentlemen's and Diffraction Limited's continued support of this obsolete camera.
I turned on all the check boxes and did a simple cooling from ambient to -25C.
Everything behaving as before, but really takes a long time to stabilize at -25C. I cut off (warm up) the testing at about 20 minutes and it still was colder than -25C.
Roger

 

I would like to know if the camera should not be used, or can be used over next few. months until I am travelling to USA. I live in Hong Kong and shipping is quite expensive each way. Thanks.