FW8G-STXL Guide Chip Images with ramdom "banding"

Discussion in 'STX and STXL Series Cameras' started by rodror, Jan 21, 2019.

  1. rodror

    rodror Standard User

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    Hello everyone,

    I am looking for assistance in resolving an ongoing issue. Hopefully someone else has run into this issue in the past and has a resolution.

    A little background...I own two camera packages.
    The STT-8300 with FW8G-STT and AO-T for a Televue NP101is
    The STXL-16200 with FW8G-STXL and AO-X for a 10" RC
    All in an Observatory so the equipment is not being torn down and setup all the time.

    The STT package was working fine for almost 2 years. The Guide chip started having "banding" appear in random images and was making guiding impossible. After talking to Bill Lynch, and verifying HDMI cable was tight, swapping HDMI cables and verified that the USB cable is directly plugged into the computer (no HUB) with no change, I returned it for repair which seemed to resolve the issue.

    I have since swapped the 8300 out for the STXL-16200 package on the TV 101. After several tests and tweaking in the adapters for the 8300 to 16200 package swap, I am now having the same banding issues with the 16200 Package.

    Researching this shows that SBIG assisted a user with the same issue by adjusting the GAIN is I recall correctly. Has anyone heard of this issue in the past, and if so, how does one adjust the camera properties to eliminate this banding issue.

    Attached are photos of the FW8G issue.

    Thanks,
    Randy

    FW8G Banding.png
     
  2. Doug

    Doug Staff Member

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    That does not look like a gain problem. It may indicate a problem with the substrate bias on the guide sensor. But before we get too alarmed about this... make sure you aren't massively overexposing the sensor. That can produce strange artifacts like this.
     
  3. rodror

    rodror Standard User

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    Thanks for the reply Doug. I could have recalled the GAIN setting incorrectly. The symptoms were the same (banding), the camera STT-8300 camera and FW8G-STT was in the article I read, but for the life of me I cannot find the article again! IF I recall, Bill Lynch said he had to replace a circuit board in the 8300 camera and the FW8G-STT to resolve the issue with my 8300.

    On my STXL-16200 camera this is happening on all exposures from .5 sec to 2 sec exposures.
     
  4. Doug

    Doug Staff Member

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    The guide cameras in both filter wheels are identical. Can you get the two cameras beside each other for a test? Just cross-connect the HDMI cables so that the STT camera connects to the STXL wheel, and the STXL camera connects to the STT wheel. (Just the HDMI cables; the I2C cables can stay where they are.)

    Then take very short guider images with both cameras (block the light so they are not saturated). This will tell you whether the problem is in the guide camera or the main camera.
     
  5. rodror

    rodror Standard User

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    I assumed that was the case.
    That sounds like a great test, however, it would be impossible to do that since I only have the single pier / mount in the OBS.
     
  6. Colin Haig

    Colin Haig Staff Member

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    Doug was suggesting you could do this on a workbench, not on a second mount.
     
  7. Doug

    Doug Staff Member

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    Correct. All you need to do is get the two cameras near enough to each other that you can crisscross the cables.
     
  8. rodror

    rodror Standard User

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    This makes much more sense. :) Thanks I will try this.
     
  9. rodror

    rodror Standard User

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    Thanks for the clarification Colin.
     

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