An issue with SBIG STF 8300M shutter noise during imaging and partially black frames

Discussion in 'STF Series CCD Cameras' started by Leo Shatz, Dec 27, 2019.

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  1. Leo Shatz

    Leo Shatz Standard User

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    I'm an onwer of this camera since about 2014, and although I didn't use it extensively, so far I hadn't experience any major problems with it. In the last outdoors test session I've encountered a problem as described in the message header. The clicking sounds and partially exposed frames happened almost in %30 of the frames. For short F&F frames of less than 1 second, it happened few times per minute. Changing SBIG FW5 positions didn't have any effect on the problem. I haven't turned on camera cooler during the test.

    The following day I've tried taking exposures with camera indoors and I heard only one click during exposure while the problem didn't repeat any more during approximately 30 minutes of running exposures.

    I understand it could be a problem with shutter mechanics and sensitivity to ambient temperature, I'd be glad to have some directions of what should I try to do before sending the camera for repairs, as it could be something trivial like adjusting the screws.

    The camera still creates its usual series of clicks during power-up phase (for this test it was powered from the mains AC/DC converter followed by a high quality DC/DC regulator with low ripple voltage and set at 12.75V DC fixed level).

    Thanks,

    Leo Shatz
     
    Leo Shatz, Dec 27, 2019
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  2. Colin Haig

    Colin Haig Staff Member

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    Hi Leo,
    Sorry to hear you are having a problem. Here's a few thoughts:
    Can you provide the camera Serial Number ? It's on a sticker on the side.

    Let's do some tests on your workbench / kitchen table.
    For starters, can you see the shutter operation by looking down the nose of the camera ?
    You might have to change your filters to a clear filter position to see it distinctly.
    When the shutter is closed, does it completely cover the opening?
    When open, is it fully open? (You said it wasn't 30% of the time).
    Can you upload a FITS image showing a bad frame? (use the Upload a File button to the lower right).

    Can you try the original power supply that came with the camera?
    Does it behave any differently?

    I don't understand what your field power setup was. eg "AC/DC converter followed by a DC/DC regulator." doesn't make much sense - a line powered 12VDC power supply normally has regulation. What voltages/currents are we talking about with this setup?
     
    Colin Haig, Dec 27, 2019
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  3. Leo Shatz

    Leo Shatz Standard User

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    Hi Colin, the SN is 83F010953.

    The shutter is fully covering the sensor when it's idle. I was able to see its operation when I run the test indoors (double curtain at start of frame followed by complete closure at the end). I have a short video recorded showing that, it'll take me some time to upload it together with sample partially black frame.

    As for the power setup, I usually do my imaging using mobile setup with a car battery hooked up to the isolating DC/DC stabilizer/converter which results in clean filtered output. The same DC/DC converter can receive its input power either from the car battery when I'm in the field, or from the mains AC/DC converter by Powerwerx (it's a solid high quality power supply converter) when I run some tests at home. In either case the camera is powered up from 12.75V DC power source.
     
    Last edited: Dec 27, 2019
    Leo Shatz, Dec 27, 2019
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  4. Colin Haig

    Colin Haig Staff Member

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    Hi Leo, thanks for the info.
    Looking forward to seeing the FITS image.

    Is it a Powerwerx SS30DV power supply ? I have one, it's quite good.
    https://powerwerx.com/ss30dv-desktop-dc-power-supply-powerpole

    What make/model is the converter?
    I use an Alinco DM330MVT pwoer supply to a West Mountain Radio EPIC PwrGate or Super PowerGate PG40S for battery/power supply to my equipment.
    http://www.westmountainradio.com/product_info.php?products_id=epic-pwrgate
    No need for any DC/DC converters or filters. Battery power is the cleanest there is, so there should be no need for a converter of any sort. If it's an MFJ battery booster, the old ones were very electrically noisy - a lot of spikes on the output due to poor filtering.

    Am glad to hear the shutter is fully covering the sensor at idle.

    Another thought for you would be to carefully remove the filterwheel/front cover of the camera and visually inspect that none of the screws are hitting the shutter disc, and that the shutter disc turns freely.
     
    Colin Haig, Dec 27, 2019
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  5. Leo Shatz

    Leo Shatz Standard User

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    Leo Shatz, Dec 27, 2019
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  6. Colin Haig

    Colin Haig Staff Member

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    Thanks, yes, from the JPG the shutter is not getting fully out of the way.

    Can you post the FITS image?
    That way I can look at the details of how the exposure was taken.

    Am thinking this may have to go in to @Bill at the SBIG Service and Repair Center in California for service.
    Drop him an email to bill at sbig dot com and ask him for details on sending it in.
     
    Colin Haig, Dec 27, 2019
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  7. Leo Shatz

    Leo Shatz Standard User

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    Ok, here is a link to FITS file https://drive.google.com/open?id=1ujca58Ck_OFvFYZk2DHzCbWBomLiKv8b

    I'd like to try fixing the issue at home if it's something trivial I can do myself. Otherwise it'll be international shipment with extra costs and delays.
    Besides, I'm concerned that the problem is not consistent and it will be hard to reproduce with potential of repeating cycles of tests and repair o_O

    Thanks!
     
    Leo Shatz, Dec 27, 2019
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  8. Colin Haig

    Colin Haig Staff Member

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    Hi Leo, thanks for the FITS.
    Looking at the file, it appears the shutter is "stuttering" - it is opening in odd steps. This probably means the motor has a problem and will need to be replaced.
    leoshatz_shutter.png
    If you look at this image, you can see the shutter opened in 2 steps, not just one. The left side of the image will show you.
    Try running it off the original power supply.
    Have you tried using CCDOPS or MaxIm to take a bunch of images? Do you get the same behaviour as Sequence Generator Pro?
    Temperature of 14C is nothing - these cameras happily run in very cold weather, so I don't think that is it.
    Pop the lid carefully and have a look. It may be there is dirt/dust/bugs or something that has gotten in.
     
    Colin Haig, Dec 27, 2019
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  9. Leo Shatz

    Leo Shatz Standard User

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    Hi Colin, many thanks for suggestions! I'll try them and will run some more tests.
    If shutter motor needs replacement, can I do it myself by ordering a new part from the company?
    A related question - if I remove the filter wheel mounting does it expose the sensor chamber to an open air (in other words - will it require desiccant plug drying cycle?)
     
    Leo Shatz, Dec 27, 2019
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  10. Doug

    Doug Staff Member

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    These stepper motors don't fail very often, especially with the very light loading - it's just holding the lightweight shutter after all. It may just be some sort of mechanical interference. Why don't you pop off the filter wheel and then try operating the shutter? Watch what it does and see if it is rubbing against something, etc.

    There is a sealed chamber inside the camera. Removing the wheel will not affect it.
     
    Doug, Dec 27, 2019
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  11. Colin Haig

    Colin Haig Staff Member

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    Thanks Doug.
     
    Colin Haig, Dec 27, 2019
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  12. Leo Shatz

    Leo Shatz Standard User

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    That sounds like a plan. Thanks!
     
    Leo Shatz, Dec 27, 2019
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  13. Bill

    Bill SBIG Service and Repairs Staff Member

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    Several factors could be in play here. Power being one of them. Definitely try the original power adapter. Ambient temperature could be another. Based on the serial number, the camera was manufactured in mid 2013. There was an issue with the motors behaving erratically in low ambient temperatures back in the 2011-2012 time frame but it occurred at temperatures much lower than 14C. It could be that the motor just needs a small adjustment although I don't know why it would be out after all these years. I'd be interested in seeing the shutter alignment when it is open. If you an iPhone and have Facetime, perhaps we can connect and do a quick analysis. Do you have CCDOps?

    -Bill
     
    Last edited: Dec 28, 2019
    Bill, Dec 27, 2019
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  14. Leo Shatz

    Leo Shatz Standard User

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    Hi Bill, I've sent you a private message with recorded video clip. I'll try few things during this weekend and let you know if problems still remain. I have downloaded CCDOps, so we can try it later.

    Thank you!
     
    Leo Shatz, Dec 27, 2019
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  15. Leo Shatz

    Leo Shatz Standard User

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    I've changed the voltage of my DC/DC converter to 12.10V to match the original power supply output level - and that apparently seems to solve the problem. I'll continue to test my setup for any signs of shutter problem.
    In any case, if such need will arise, I suppose, I could replace the motor by myself instead of sending camera for repairs. Can I order the shutter motor kit alone?
     
    Leo Shatz, Dec 30, 2019
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  16. Bill

    Bill SBIG Service and Repairs Staff Member

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    Glad to hear it Leo. Replacing the motor isn't as simple as it sounds. The replacing is simple but getting the shutter aligned properly is something else altogether.

    -Bill
     
    Bill, Dec 30, 2019
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