STX16803 Cooling Issue

Discussion in 'STX and STXL' started by Gu Lim, Apr 18, 2020.

  1. Gu Lim

    Gu Lim Cyanogen Customer

    Joined:
    Aug 9, 2019
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    Location:
    Seoul, South Korea
    We are using SBIG STX 16803 CCD on Planewave CDK14 remotely.
    Temperature is usually setting on -15 celcius degree and it's been no issues recently. Ambient temperature is about 17 deg. However, several days ago, the temperture stops decreasing under 4.6 degree. Rebooting CCD and software on PC didn't work to this issue. So we requested replugging CCD, driver updates to staff at the observatory but the same issue occurred (stopped at 8 degree set to +5 degree) even if the cooler works fine.
    We checked if cooling is okay or not using Maxim DL and The Sky X but this is not related to the issue.

    2 possible reasons are suggested : vacuum problem and dessicant.
    (1) But according to manual, STX 16803 does not seem to have a vacuum chamber. It says it can improve the cooling a bit - We don't know how much it helps... Purging the gas is not easy at the site since staff there have no equipment to do and worry about damaging ccd.

    (2) Before sending CCD, frost issue on the images are found so dessicant was replaced. Can this be the problem?

    We are looking for solution or any comments about this issue. Additionally we consider to send another ccd if this issue continues...
    Best regards,
    Gu Lim
     
  2. Colin Haig

    Colin Haig Staff Member

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    With ambient temperature of +17C, that camera should cool to -25C to -30C without any difficulty.

    This sounds more like an DC +12V power problem - the cooler electronics draw several amps of current.
    I recommend you check that you are using the original power supply that came with the camera.
    Check that it is providing at least +12V to +14V.
    Check that there are no broken wires in the extension cable between the power supply and camera.

    There is normally no need to purge the CCD chamber. This has to be done with extreme care.

    If you have frost, bake the desiccant, replace it, and let the camera dry out. It should not affect the cooling very much, and will prevent frost.

    If you cannot find the source of the problem, please contact @Bill for repair service. His email is: bill (at) sbig (dot) com
    We will need the serial number of the camera, and when/where you bought it.
     
  3. Doug

    Doug Staff Member

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    Let me reinforce Colin's statement not to attempt to purge the chamber. The most likely outcome is implosion of the sensor window.

    Recharge the desiccant following the instructions in the manual. This should be done as an annual service, to prevent any chance of frost forming in the chamber.

    Check whether the fan is functioning properly. If not then the camera will not be able to cool very well. Also make sure it is set to either Auto or maximum speed.
     
  4. Gu Lim

    Gu Lim Cyanogen Customer

    Joined:
    Aug 9, 2019
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    Location:
    Seoul, South Korea
    Thank you for your kind comments.
    Seeing last images taken right before the issue, there was no frost feature.

    As your comments, the staff there said that the power supply cable is not from SBIG. (the figure attached)
    So we are about to purchase STX / STXL / STL Power Supply ($300) sending this to Chile (the installed site) directly, not via South Korea.
    In order page, there is "Ship to a different address?" box. Can we order this cable from the manufacturer to the observatory in Chile via checking this box?
    If not, do you know how to do this?
     

    Attached Files:

  5. Doug

    Doug Staff Member

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    Depending on the vintage, the power supply might not say SBIG on it. Various suppliers have been used in the past, including ELPAC.

    If the power supply voltage gets too low, the cameras will kill the cooler power entirely to safeguard itself. It won't just stop at a certain temperature; it will come back up to ambient. So I'm thinking the power supply is not the problem.

    What is your camera's serial number?

    Did you check the fan for correct operation?
     
  6. Gu Lim

    Gu Lim Cyanogen Customer

    Joined:
    Aug 9, 2019
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    Location:
    Seoul, South Korea
    Dear Doug,

    Oh, various cables were used in the past.
    Staff said the fan works fine.

    I have one more question.
    Attached figures are connection pins for power supply at the site.
    In order to get voltage correctly, do you know which pin should be used?

    Serial number of the camera is 14010315.
    Best regards,
    Gu Lim
     

    Attached Files:

  7. Doug

    Doug Staff Member

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