Resolved SC3 shutter sticking

Discussion in 'Guiding and Adaptive Optics - StarChaser and AO' started by Mark Marfoglia, Jun 19, 2025.

  1. Mark Marfoglia

    Mark Marfoglia Cyanogen Customer

    Joined:
    Oct 19, 2014
    Messages:
    204
    Location:
    Montreal, Quebec, Canada
    My rig was idle for 5 months in the NM desert. The mechanical shutter makes a small noise when attempting darks indicating that it is being triggered, but the sensor sees no stars. I opened the cover of the SC3 and the shutter moves reluctantly, when it used to clearly slide back and forth when handling the device in my hand. Is there anything I can do to correct this myself?
     
    Mark Marfoglia, Jun 19, 2025
    #1
  2. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,801
    Perhaps it got contaminated with sand / dust? I'd suggest opening it up and hitting the mechanism with compressed air from various angles while moving it back and forth.
     
    Doug, Jun 19, 2025
    #2
  3. Mark Marfoglia

    Mark Marfoglia Cyanogen Customer

    Joined:
    Oct 19, 2014
    Messages:
    204
    Location:
    Montreal, Quebec, Canada
    Your suggestion worked but not for long. I have it open and connected, and putting it thru a sequence of alternating lights and darks. It just does not seem to have enough strength and eventually sticks. A little nudge gets it moving again but that is not going to cut it. Can I lubricate it?
     
    Mark Marfoglia, Jun 20, 2025
    #3
  4. Mark Marfoglia

    Mark Marfoglia Cyanogen Customer

    Joined:
    Oct 19, 2014
    Messages:
    204
    Location:
    Montreal, Quebec, Canada
    Graphite?
     
    Mark Marfoglia, Jun 20, 2025
    #4
  5. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,801
    Might make a mess. Maybe try a dab of petroleum jelly?

    That said... I have another thought:

    upload_2025-6-20_14-18-41.png

    The runners that the shutter runs through was made of plastic in earlier versions of the SC-3. We later switched that to anodized aluminum because there was some tendency for the plastic to flex when the four mounting screws were tightened, and that increased friction with the shutter. So the assembler had to be very careful with how much torque was applied to those screws.

    If your runners are plastic you might try loosing the four screws just a wee tiny bit.
     
    Doug, Jun 20, 2025
    #5
  6. Mark Marfoglia

    Mark Marfoglia Cyanogen Customer

    Joined:
    Oct 19, 2014
    Messages:
    204
    Location:
    Montreal, Quebec, Canada
    They are indeed plastic, and the graphite carefully applied made it worse. It’s very tight. However, backing off the screws really made a difference, in my hands at least. I will see tonight if it works at all angles. Thanks and keep thinking:)
     
    Mark Marfoglia, Jun 20, 2025
    #6
  7. Mark Marfoglia

    Mark Marfoglia Cyanogen Customer

    Joined:
    Oct 19, 2014
    Messages:
    204
    Location:
    Montreal, Quebec, Canada
    Initial testing is positive. Thx for your help. Cheers!
     
    Mark Marfoglia, Jun 21, 2025
    #7
  8. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,801
    Great! I'll mark this as resolved. Feel free to reopen if you have trouble again.
     
    Doug, Jun 21, 2025
    #8

Share This Page