Staff Assigned: Bill Lynch Horizontal banding (random)

Discussion in 'Image Capture' started by Doris Thibeault, May 5, 2017.

  1. Doris Thibeault

    Doris Thibeault Cyanogen Customer

    Joined:
    Apr 21, 2015
    Messages:
    14
    Hi !
    My ST8 camera now longer displays a flat background. Instead I get some random horizontal banding (see attached file). This makes precise photometry impossible. I tried changing the usb cable for a newer and shorter one; I also plug the new cable straight into the computer, no usb hub. I stll get the banding.<It does it in all modes, light, darks, biais etc..
    Any idea what to do next?

    Doris Thibeault
     

    Attached Files:

  2. William B

    William B Cyanogen Customer

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    Location:
    Christchurch, Dorset UK
    Could be a power supply problem that is generating the noise, check the power plug and socket to the camera is clean and not oxidised and that the pins are not loose, if running the camera off a mains adaptor try test running off a battery to eliminate the mains power module.

    Has anything changed to the environment around the camera such as new WiFi or Bluetooth transmitters that may be inducing noise into the power supply or USB cables? if so, try fitting ferrite clamps over both ends of the camera power cable and USB cable.

    Check for possible earth leakage from the PC/Laptop to ground via the camera. Laptop and PC power supplies can become leaky after a few years of operation and if the leakage path to ground is via the camera this can induce the banding noise, if using a laptop try running on internal battery only to see if the noise disappears.

    Also, check the camera off the telescope/mount, just the camera alone, a mount power supply problem can also induce leakage currents that find their way to ground via the camera and PC.

    Otherwise, inside the camera it may be an internal power supply component problem or a poor contact with one of the internal inter-board or sensor connectors which would need the camera to be returned for service.

    William.
     
  3. Doris Thibeault

    Doris Thibeault Cyanogen Customer

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    After further eximination, I tried with the power supply alone with the camera, without extension cable. There is current on the Power suply pins. But now the camera wont start. The red led is no longer on....is the internal supply dead?
     
  4. William B

    William B Cyanogen Customer

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    I think for the ST8 camera the red LED only lights and the fan runs when the camera has established communication with the PC over the USB cable. While only the power lead is connected the red LED is dark and the fan does not turn.

    To test stand-alone the camera must be connected to power, mains adaptor or battery and the USB cable must be plugged in to the PC. When the camera is connected by USB and power it should appear in Windows device manager.
     
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  5. Doris Thibeault

    Doris Thibeault Cyanogen Customer

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    Apr 21, 2015
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    Well, I finally did everything that you proposed:

    Tried without the scope power supply. Tried with the camera about 15 feet from the camera power supply; Tried with a different power cable. Tried Inside the house and in the observatory...always the same banding...

    Is the only solution left looking at Inside the camera for internal power supply...?
     
  6. William B

    William B Cyanogen Customer

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    Location:
    Christchurch, Dorset UK
    I think so Doris, the tests you have carried out point to an internal camera power supply or other electronic problem.

    It may just be a failed capacitor or resistor but I don't have any SBIG cameras and never have taken one apart so I can't advise you on this.

    You could email the SBIG service agent Bill Lynch, the address for the web contact page is below, attach the sample image or link back to this post and ask for his opinion, I am sure he would have seen similar problems with other cameras.

    http://diffractionlimited.com/support/technical-support/

    Hope you are able to have the camera repaired and be back working soon.

    William.
     
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  7. Doug

    Doug Staff Member

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    Our ability to repair these older cameras is limited by problems with parts availability; many of the electronics parts have gone obsolete. But Bill may be able to help.
     

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