FW8G-STXL fails: "CFW Motor Timeout"

Discussion in 'Filter Wheels' started by Eric Dose, Dec 4, 2016.

  1. Eric Dose

    Eric Dose Cyanogen Customer

    Joined:
    Jun 20, 2015
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    Location:
    Albuquerque, New Mexico
    After a year of great service, my FW8G-STXL has started failing after about 2-20 filter changes; CCDOPs gives a message dialog box: CFW Error // Error Occurred in the Query State // CFW Motor Timeout.
    • The filter wheel is mounted on a STXL-6303E.
    • The error occurs in CCDOps 5.57 (giving error dialog box noted above), and in MaxIm 6 (fails silently).
    • SBIGDriverChecker64, drivers, and firmware are all fully up to date.
    • Asynchronous USB IO is turned on.
    • I see nothing amiss at all in the interior. Filters are secure, there is nothing catching on the belt, and the carousel and gears turn smoothly by hand and without carousel wobble.
    • The carousel's center hex nut, which I assume is some kind of tension adjustment, has been tightened and loosened without apparent effect.
    • The power supply has always been inactive during all cable connections or disconnection.
    My very active variable star observatory is down until this is fixed. I would be grateful indeed for any guidance.

    Eric Dose
    Bois d'Arc Observatory, Kansas
     
  2. Tim

    Tim Staff Member

    Joined:
    Sep 25, 2014
    Messages:
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    Has anything changed in your setup recently either hardware or software? If nothing has changed, it may require service. I suggest you give Bill Lynch a call to see if he can help:

    Bill Lynch – SBIG Service & Repair Center
    3769 Constellation Road, Unit D
    Lompoc, CA 93436
    Bill Lynch – bill@sbig.com
    Phone: (805) 308-6979

    Note: Please contact our authorized service & repair center for an RMA number prior to returning your equipment.
     
  3. Eric Dose

    Eric Dose Cyanogen Customer

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    Location:
    Albuquerque, New Mexico
    No, no hardware changes for a year, and no software other than SBIG's recent driver update (but the problems existed before and after that update).

    Sounds like I'd better call Bill. I want to rule out a low-voltage problem before I ship anything (my camera unit strangely has no voltage LEDs as shown in the manual).
     
  4. EricC

    EricC Cyanogen Customer

    Joined:
    Jan 31, 2015
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    195
    I had the same issue with my new CFW8-STXL. The colder it got the quicker I started getting motor timeouts. Indoors it ran forever without an issue.
    I asked Bill @ Service if there was anything I could do. He suggested very slightly loosening the belt that moves the filter wheel. He said if it's too tight it might bind the motor and if it's too lose it will slip. I loosened the belt and the problem appears to have been fixed.
    You have to remove the filter wheel from the camera so you can get to the bolt on the bottom. Before doing so, note how tight the belt is so you know whether or not you've gone too far. Loosen the bolt just enough that you can move the arm and gear that's attached to it every so slightly.
     
  5. Eric Dose

    Eric Dose Cyanogen Customer

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    Location:
    Albuquerque, New Mexico
    Well, yes, if you just spoke with Bill, then you have the benefit of his having my own camera and filter wheel for several weeks.

    The problem is that there is no clear way to "note how tight the belt is" or to know "whether you've gone too far" or even which sprocket to adjust. And the design seems real wrong if we have to remove the whole filter wheel from the camera just to adjust a belt's tension. If it's really that critical to operation--and it is--as well as that touchy--and mine was--then we should be able to adjust the tension without even taking the camera off the scope, the same way we can adjust the guide mirror position.

    Bill says mine is on its way back to me and working. Good. I have bought some tension gauges and will measure its tension before mounting it. If it does prove to perform now, at least I'll know what the target tension is.
     
  6. EricC

    EricC Cyanogen Customer

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    Eric D, Bill told me which sprocket to adjust, I just didn't mention that in my last post. I gather that adjusting the tension isn't normally needed, hence the reason it's not easy to do. Perhaps if a bunch of people have the same issue we did, a future version of the filter wheels will include a way to easily adjust the tension.

    I will be curious to hear back once you have measured the belt tension with your gauges. I thought about that when adjusting mine, but I don't have a gauge and don't know what the correct tension is anyhow.

    BTW, when I was talking to Bill about the belt tension, he mentioned the belt on the unit he was working on at the moment seemed tight - it may have been yours. I had the impression he noticed as he was talking to me.
     
  7. Rolf Sveinhaug

    Rolf Sveinhaug Cyanogen Customer

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    May 15, 2015
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    I got this error also now, but I only gets the warning message in the TSX Camera Ad On, when I use Maxim DL, I can see "Filter moving" as there was no problem, but my whole RGB session was taken with the red filter, so the Combining of the RGB's was a sad story, but I have a lots of good red data :)
     
  8. Bill

    Bill SBIG Service and Repairs Staff Member

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    I don't have one in front of me to verify but I'm pretty sure the FW does not have to come off of the camera to make this adjustment. The front cover does have to come off but the rest of the FW can stay mounted to the camera. With the front cover removed, the nut for the sprocket can be accessed from the top and the screw head from the bottom which is external to the camera body. The picture below is a an unmounted STT FW but I think it's basically the same in the STXL.

    Sprocket Nut and Screw.jpg
     
  9. EricC

    EricC Cyanogen Customer

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    The STXL filter wheel is different from the STT one, at least on my STXL wheel bought a couple months ago.
    The screw on the bottom of the sprocket that needs to be loosened goes inside the camera. Other than the motor, nothing sticks out the bottom of the filter wheel when it's attached to the camera.
    Eric
    CFW8-STXL filter wheel.jpg
     
  10. Doug

    Doug Staff Member

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    Yes the tension adjustment sprocket screw ends up inside the camera when the filter wheel is installed.
     
  11. Bill

    Bill SBIG Service and Repairs Staff Member

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    Sorry for the bum info.
     
  12. Rolf Sveinhaug

    Rolf Sveinhaug Cyanogen Customer

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    May 15, 2015
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    The motor-timeout on my FW8G-STXL filterwheel was not a belt tension problem, but the beltdrive motor had seized!
    Thanks to Bill for super rapid service, a new motor is allready on the way with UPS.
     
  13. EricC

    EricC Cyanogen Customer

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    Rolf, how were you able to determine the issue was with the motor and not the belt?

    After I slightly loosened my belt I didn't see a problem in 150 filter changes. The next day, though, I got a filter error but failed to write it down. It was not the "motor timeout" error I had seen earlier, though. Perhaps my motor is also part of the problem with my FW8G-STXL as well.
     
  14. Rolf Sveinhaug

    Rolf Sveinhaug Cyanogen Customer

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    Eric- took of the belt and tried to turn the motor shaft, but it was stucked, an simple electromgnetic motor like this with no power connected, has to move.
     
  15. Eric Dose

    Eric Dose Cyanogen Customer

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    Location:
    Albuquerque, New Mexico
    Have my filter wheel back--thanks, Bill!--and it worked well tonight.

    I know Bill took some care in adjusting my filter wheel's sprockets and belt, so to record a reference before installing it, I measured 3 moments that I could do without interfering with his work. They are:
    • force to move wheel between filter positions: 40-50 grams force (0.4-0.5 N) as measured at filter center (pretty sure that mine was way higher when I sent it in for repair)
    • force to move wheel out of a filter position: 250-300 grams, again measured at filter center
    • force to cause 5 mm lateral displacement of belt (middle of longest belt segment): 500 grams
    These were measured with a cheap spring scale, and could be off by 10%, which wouldn't matter. The first two were just a matter of looping a soft twist-tie through a filter hole, hooking that with the scale and tugging gently until I got motion.

    I'm still not sure I know how to make adjustments if that time comes, but at least I can rule tensioning in or out.
     

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