Fans don't operate

Discussion in 'Aluma CCD Series' started by Greg Crawford, Sep 16, 2019.

  1. Greg Crawford

    Greg Crawford Cyanogen Customer

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    I developed a problem with the fans of my Aluma 8300 today. When connected and powered on I get the normal few tick, tick, ticks, and connection from MaxIm DL 6.20 is made. It is possible to turn on cooling and the cooling begins to happen with the temperature going down. However, the fans don't come on as they usually do. After a short period of time the heat sink on the camera starts to get rather hot, so at that point I turn off the cooling. From this I conclude that the fans are not doing their job of cooling the camera's heat sink. I am looking for an easy way to correct this. I am not keen on having to send the camera all the way back to Canada again.
     
  2. Colin Haig

    Colin Haig Staff Member

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    Can you shine a flashlight in to the fans, and see that they are not plugged up with dust/dirt, and that they rotate?
     
  3. Tim

    Tim Staff Member

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    Were they working, and then stopped?

    If you removed the back cover with the fans on it, and had to re-plug the fans in, sometimes they do not get plugged in correctly or are misaligned. Have a peek inside and make sure the 4 fan pins are plugged in all the way.
     
  4. Greg Crawford

    Greg Crawford Cyanogen Customer

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    Hi Colin and Tim,

    The fans were working prior to this, but the pitch of sound they omitted sometimes varied in a short space of time. I assumed that this could be caused by an attempt of the system to maintain the temperature precisely, but it now seems to me to be an indication they were on their way out. I took off the back plate of the camera to which the fans are attached and unplugged the fans from the pins they were plugged into. Then I plugged them back in and turned the camera on. Everything else seemed to work - the filter wheel revolved to filter number one; the AO8 did its customary wobble on start, the camera connects and will download an image, even the cooling comes into effect, but the fans wont rotate. So I unplugged the fans and took the back plate which holds them off. I applied 12 volts from a laboratory power supply to the exposed parts of the fan plugs (red for +ve, black for -ve) and the fans did not rotate. After disconnecting them from the power, I tried to move the fan blades and they rotated easily. My conclusion is that the fans have had it. I noticed that the fans are rated for 12 volts, but only 0.21 amps. From this I have speculated that they are limited in their ability to withstand heat that might on the one hand come from a greater current draw, but also the heat from sustained operation over time even within that current limit. But then, I am not an electronics technician, so you have to take my ramblings with a grain of salt. :)
     
  5. Colin Haig

    Colin Haig Staff Member

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    Hi Greg,
    You misundertand the labelling on electronic devices. 12V 0.21 A means that AT MOST the fans will consume 210mA at 12V. It has nothing to do with it.

    @Tim am wondering if we could just send Greg a new backplate with fans attached, or a pair of fans pre-wired? Am not sure if you need to check things out further... doing my own bit of speculating here.
     
  6. Tim

    Tim Staff Member

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    Sure, we can ship out the back cover with fans, and you can swap it out. Though we are very curious to get to the bottom of the problem so we can ensure it does not happen again. Could we ask that you send the old one back so we can inspect it?
     
  7. Greg Crawford

    Greg Crawford Cyanogen Customer

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    Certainly! Should I send it to 59 Grenfell Crescent xxx?
     
  8. Tim

    Tim Staff Member

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    Yes, thats correct. Same as in my signature below.
     
  9. Greg Crawford

    Greg Crawford Cyanogen Customer

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    I've just realised that the serial number of the camera is on the back plate. Will this create a complication?
     
  10. Tim

    Tim Staff Member

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    No, its ok. We have it on file.
     
  11. Greg Crawford

    Greg Crawford Cyanogen Customer

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    OK, I've just posted it at 2019-09-19 16:35 my local time (=GMT +10). I'll send the tracking number privately.)
     
  12. Colin Haig

    Colin Haig Staff Member

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    Thanks Greg!
     

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