FW8S-STXL motor stops

Discussion in 'Filter Wheels' started by EricC, Apr 18, 2022.

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  1. EricC

    EricC Cyanogen Customer

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    A few years ago my FW8S-STXL filter wheel would not work well when it got around freezing. The motor wouldn't turn the wheel all the way. I contacted Bill Lynch who suggested slightly loosening the belt and that fixed the problem until recently.

    Tonight I was there when it stopped working (it was around 60 F, 15 C). I heard the motor start to move the wheel, then it sounded like it was struggling, then it stopped.

    Whenever the filter wheel stops working, a power cycle gets it working again, but I hate doing that because it's bad for the sensor. And, that makes it impossible to do unattended imaging.

    Can I get a new (ideally more powerful) motor, and/or a new belt? Or should I try tightening/loosening the belt again?

    The device is in a remote observatory so I don't want to send it in since I won't be back for about 6 months, which means I won't be able to take pictures that long.

    Help!

    Thanks - Eric
     
    Last edited: Apr 18, 2022
    EricC, Apr 18, 2022
    #1
  2. Doug

    Doug Staff Member

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    It sounds like it might need a motor replacement.

    @Bill should be able to help you with that.
     
    Doug, Apr 18, 2022
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  3. Bill

    Bill SBIG Service and Repairs Staff Member

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    Eric,

    Send me an email, bill@sbig .com and I will give you the details for sending it in.

    -Bill
     
    Bill, Apr 22, 2022
    #3
  4. EricC

    EricC Cyanogen Customer

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    I replaced the motor a few months ago but the problem still exists. I tried loosening the belt again but it didn't help. When the problem happens, the filter wheel often begins turning (maybe a position or two), then grinds to a halt. Cycling the power almost always fixes it for a while. Does this give a clue as to what's causing the filter wheel to stop?
    Is it possible the wheel is rubbing on something? How would I troubleshoot that?
    Any other ideas?
     
    EricC, Nov 21, 2022
    #4
  5. Colin Haig

    Colin Haig Staff Member

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    What software, drivers, and firmware do you have, specifically?
    For example, these are good:
    SBIG Driver Checker 4.05
    sbigudrv.dll 4.99 build 7 or 5.1.1.0
    MaxIm DL Pro 6.30
     
    Colin Haig, Nov 21, 2022
    #5
  6. EricC

    EricC Cyanogen Customer

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    Colin, I'm up to date with drivers and firmware. I just tied tightening the belt quite a bit and will see how that goes.
    With it looser, it would sometimes start oscillating which may have caused the motor to sense no pressure (not sure if that's the correct word), then a lot of pressure.
    I assume the motor stops when it senses too much pressure, for example, every time the little wheel goes into a slot that appears to cause a lot of pressure.

    SBIG drivers.jpg SBIG firmware.jpg
     
    EricC, Nov 21, 2022
    #6
  7. EricC

    EricC Cyanogen Customer

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    Forgot to say, I use Sequence Generator Pro with the SBIG drivers.
     
    EricC, Nov 21, 2022
    #7
  8. Colin Haig

    Colin Haig Staff Member

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    Here's a thought: CCDOps has a Filter Wheel exerciser function that can randomly/continuously run the filter wheel.
    Why not give that a try and let it run for several minutes. It will give the wheel a good workout.
    You can get it here: https://cdn.diffractionlimited.com/downloads/InstOps.exe
    On the menu, Filter... CFW Exerciser

    Other things to check:
    Make sure the power supply is putting out +12V or slightly more (eg 13V). Check the LEDs on the side of the camera for low voltage.
    If you have used through-the-mount cabling, there could be a significant voltage drop, and so the motor won't get enough juice.
    Check all cable wiring to the camera from the power pack - sometimes a wire breaks inside the DC extension or power pack DC output due to repeated flexing.
     
    Colin Haig, Nov 22, 2022
    #8
  9. EricC

    EricC Cyanogen Customer

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    Colin, I'm running the exerciser now.
    I'm using the power brick that came with the camera. I have an adjustable power supply; what's the maximum voltage the STXL-16200 camera can support? I use heavy-gauge wire through the mount, but can check the voltage none-the-less.

    Just curious - when I click on the highlighted button, the dialog box on the right appears. Do the FAILs matter?

    upload_2022-11-25_18-38-21.png
     
    EricC, Nov 25, 2022
    #9
  10. EricC

    EricC Cyanogen Customer

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    I get this after various amounts of time. Is there any additional information I can get from CCDOps?

    In order to get the filter wheel working again I have to go to Filter -> Calibrate/Initialize then can restart the test.
    The ambient temperature is around freezing, but his has happened around 50 F / 10 C.

    I haven't checked the voltage yet - we got a lot of snow and I can't get up the mountain to my observatory.


    upload_2022-11-25_19-31-3.png
     
    EricC, Nov 26, 2022
    #10
  11. Colin Haig

    Colin Haig Staff Member

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    The error graph isn't really relevant.
    However, the CFW Error is indicating a problem with the filter wheel not responding properly.
    Possibly the position sensor is dirty or misaligned or defective.
    Try a Giottos Rocket air blower to clean any dust/dirt off of it. Be careful to protect the filters when doing so.
    Also check for broken/frayed wires.
     
    Colin Haig, Nov 28, 2022
    #11
  12. Doug

    Doug Staff Member

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    Compressed air won't help - the FW8G sensors are magnetic. (Only FW7-STX has optical sensors.)
     
    Doug, Nov 28, 2022
    #12
  13. Colin Haig

    Colin Haig Staff Member

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    Whoops. I forgot! Was thinking both the STXL and STX were optical. Perhaps the board is malfunctioning?
     
    Colin Haig, Nov 28, 2022
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  14. EricC

    EricC Cyanogen Customer

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    Doug, Colin,
    what's the max voltage the STXL-16200 can take? I'm using the power supply that came with the camera but have an adjustable power supply I can try. I've only been able to check the LEDs on the side of the camera when it was around 60 degrees F (15 C) and it was fine. The filter wheel checker also went over 1000 at that temperature.
    It normally fails around 40-50 degrees F (4 - 10 C) or lower.
     
    EricC, Nov 29, 2022
    #14
  15. Doug

    Doug Staff Member

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    The manual recommends a maximum of 14V. I'm not going to recommend going beyond that, and you do so at your own risk.

    I did have a quick look at the circuit design to see what safety margin was used. It is definitely unsafe to go to 16V.

    Also the fan is often the limiting factor; several different models were used over the years so I can't tell you what the absolute voltage limit is on the fan. There is about 1V drop between the input terminals and the fan.

    Personally, I'd stick to 14V max.
     
    Doug, Nov 30, 2022
    #15
  16. EricC

    EricC Cyanogen Customer

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    Doug,
    Thanks for that info. I'll set it power supply to slightly under 14V just to be safe.

    Any idea why power cycling the camera would get the filter wheel working again, usually for the rest of the night?
     
    EricC, Nov 30, 2022
    #16
  17. Doug

    Doug Staff Member

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    Power cycling the camera also power cycles the filter wheel...

    This sounds like it could possibly be a weak motor. If it has a bad bearing or magnet then that could degrade its torque.

    If you want the problem permanently resolved it would be best to send it back to Ottawa for service.
     
    Doug, Nov 30, 2022
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  18. EricC

    EricC Cyanogen Customer

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    Doug,
    This is a new motor as of earlier this year. The old motor did the same thing.
    I put power supply with 13.6 volts so I'll see how that goes.
     
    EricC, Dec 2, 2022
    #18
  19. EricC

    EricC Cyanogen Customer

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    The 13.6-volt power supply didn't help.

    Are there any other choices short of sending it in? It's in a remote observatory that I only get to every few months so if I sent it in I wouldn't be able to take pictures.
    Do you sell used filter wheels?
     
    EricC, Dec 11, 2022
    #19
  20. EricC

    EricC Cyanogen Customer

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    Doug, Colin,
    Is it possible the STXL-16200 is the cause of my filter wheel stopping? For example, the camera isn't supplying enough power to the filter wheel when it's cold outside?

    I noticed you still have a few filter wheels for said, and I'd be willing to buy one if I was sure the problem with my current filter wheel was with the wheel itself and not the camera.
     
    EricC, Feb 17, 2023
    #20
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