STT-8300MM fan cooling system problem

Discussion in 'Legacy Models - Community Support' started by Aldrin Gabuya, Sep 13, 2019.

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  1. Aldrin Gabuya

    Aldrin Gabuya Standard User

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    Good day.

    The fan cooling system in our SBIG STT-8300mm is not working after plugging it back and forth. The CCD is being recognized by CCDOps software. The last time it worked properly was last September 11, 2019.

    Here's the link of a short video clip showing the problem: .

    Feel free to share your thoughts/suggestion on resolving this issue.

    Thank you very much. Clear skies.
     
  2. Doug

    Doug Staff Member

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    They are very dirty - they might just be gummed up. Maybe pop off the back lid and then try to clean them out with compressed air. See if they will turn by hand.

    And make sure the fan wires are plugged in.
     
  3. Aldrin Gabuya

    Aldrin Gabuya Standard User

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    Good day.

    Before cleaning, we found disconnection of the red wires on both fans (see attached images).

    Feel free to share your thoughts/suggestion on resolving this issue.

    Thank you very much. Clear skies.
     

    Attached Files:

  4. Doug

    Doug Staff Member

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    Well that's a new one. Very odd for both power wires to have failed.

    I recommend you send the camera to @Bill at SBIG Service & Repair.
     
  5. Aldrin Gabuya

    Aldrin Gabuya Standard User

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    Good day, @Doug, @Bill, and @Colin Haig . This is a different issue from the previous (resolved last early 2020) issue.

    I just have this problem wherein our SBIG STT-8300MM CCD seems to be not cooling despite connecting it with either Maxim DL or CCDOps (see attached image) as depicted in the program. The fan is working fine and the CCD's usual sound when cooling is there (indicating it's performing well; see this video: ). Drivers are up to date and camera is recognized.

    Feel free to share your thoughts/suggestion on resolving this issue.

    Thank you very much. Clear skies.
     

    Attached Files:

    Last edited: Feb 23, 2022
  6. Doug

    Doug Staff Member

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    It may need to go in to @Bill for service.
     
  7. Colin Haig

    Colin Haig Staff Member

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    I agree with Doug. It also looks like the fans and heatsinks are dirty, so service would be a good idea.
     
  8. Aldrin Gabuya

    Aldrin Gabuya Standard User

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    Good day, @Doug, @Bill, and @Colin Haig .

    Oh alright. We are situated in Abu Dhabi, UAE. What would the approximate prize for the service + shipping for it? How long will the repair service take?

    We have had this camera for over 5 years now, and it's just now that we have this issue. Is it still covered in the warranty? If it seems confidential to share here in the forum, please send the pricing and necessary details to my email aldrin@alsadeem.ae

    Thank you for your reply. Clear skies.
     
    Last edited: Feb 24, 2022
  9. Doug

    Doug Staff Member

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    Our standard warranty is two years on the camera, one year on the sensor.

    @Bill will update you on service costs.
     
  10. Bill

    Bill SBIG Service and Repairs Staff Member

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    email sent.
     
  11. Aldrin Gabuya

    Aldrin Gabuya Standard User

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    Good day.

    Few weeks after this issue was brought up, the cooling system of SBIG STT-8300MM surprisingly work for a few times when I re-tested it. And then it stopped working again.

    We asked for a 2nd opinion from someone we know who has some knowledge on cameras to check on the issue. He pointed out that the issue lies on the Peltier cooling system which failed due to possible short/open circuit, in which it doesn't cool the sensor.

    We would ask if you can provide details on replacement parts for the Peltier cooling system you use for this particular CCD (KAF-8300MM).

    Thank you very much. Clear skies.
     
  12. Doug

    Doug Staff Member

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    You can't buy just one; we purchase them in lots of 100.

    Also we have no idea if that is the correct diagnosis. There are many components in the cooling system other than the Peltier device. It could even be caused by low input power to the camera. Plus we do not recommend that the customer open the CCD chamber; the sensor is easily damaged and even more easily contaminated.
     
  13. Zoltan Derzsi

    Zoltan Derzsi Standard User

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    Hi Doug,

    I am the person who Aldrin asked to help out, here is what happened.

    At first I saw the video and thought exactly as you did - the fans are dirty, and the heatsink has clogged up with dirt. This is a very typical problem in the UAE, we have a lot of sand-based fine dust, which can cake solid with the plenty of humidity around here.

    I removed the back plate of the unit, cleaned the fans, and cleaned the heatsink. While maintaining ESD safety, we then powered it up, and inspected the insides with a thermal camera. The environment temperature was 35°C. I didn't have access to a schematic and my internet connection was slow so I didn't look up each and every component on the PCB.

    The heatsink does not get warm at all. The sensor does not get cold at all. The big black package, which I am assuming that is a DC-DC converter is 25°C above environment temperature. There are two daughterboards, which I think either some sort of buck regulators or it's some mosfet-based switching module with additional filtering. They look identical, and have SMD inductors at the top.
    The one above the DC-DC converter gets about 30-35°C above environment temperature, and its heat seems to be proportional with the cooling power reported by the software.
    The other components (FPGA, and a chip which I think is some sort of a microcontroller) are normal temperatures.

    The daughterboard left to the DC-DC converter stays at environment temperature.

    From this, I concluded that the peltier device is drawing abnormally high current, which can only happen if it's shorted. It rarely happens, but it can happen.

    I would have thought, if this was a power issue, it would also cause brown-out resets as well, which I haven't seen it doing.

    How was this designed? Are you directly switching power to the Peltier-device from the DC barrel socket? So, say if the power connector has a slight contact fault, the voltage would drop so the peltier device wouldn't power up, but the rest of the circuitry still works?


    Zoltan
     
  14. Aldrin Gabuya

    Aldrin Gabuya Standard User

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    Alright, thanks @Doug. @Bill, With that case, what would be the approximate prize for the service (is there any additional cost for the cooling system repair) + shipping for it? How long will the repair service take?
     
  15. Doug

    Doug Staff Member

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    @Zoltan Derzsi There is an adjustable-voltage DC-to-DC converter between the input power and the Peltier. It adjusts the power to the cooler based on setpoint and the temperature of the sensor. It is under firmware control. If the input voltage to the camera drops too low the firmware will automatically turn off the cooler power supply, and that can only be restored by cycling the power to the camera. It's a safety feature to prevent overcurrent on the power input.

    @Aldrin Gabuya I will have to refer that to @Bill . He can be reached directly by email at bill at sbig dot com.
     
  16. Zoltan Derzsi

    Zoltan Derzsi Standard User

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    @Doug Well, since that DC-DC converter was running rather toasty, and we didn't experience this safety shutdown feature while testing it, this would confirm to me further that the Peltier device is faulty. Please keep me updated about this, I am just curious.

    Zoltan
     

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