Resolved Compatability issues between ST-7E and SkyWatcher EQ6-R Pro mount

Discussion in 'Legacy Models - Community Support' started by CrossoverManiac, Feb 20, 2020.

  1. CrossoverManiac

    CrossoverManiac Standard User

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    I have an ST-7E with a CFW-8 filter wheel. The first time I hooked it up, my telescope would drift off target. At first, I thought it was the weight of the parallel port wire. But then I noticed the drift was entirely in the declination going downward in the negative direction. When I disconnected the RS12 cable from the CFW-8 serial port plug it stopped drifting. Also, that same downward drift happens when I try calibrating my mount in CCDOps for self-guiding.

    Then I installed the CFW-8 on another ST-7E camera that I have (yes, I have two ST-7Es. The other one came with the CFW-8 and an AO-7 but I didn't know the seller tossed the other camera in until after I made the deal.). And I had the same problem as before. So, I know it's not the camera. Then, I disconnected the CFW-8 serial cable from the ST-7E and then connected an RC Relay Connector to the serial port and ran the RJ-12 cable from it to the autoguider port on the mount. And I had the same problems as before. It would start drifting in the -Y direction until I disconnected the RJ-12 cable from the camera. So, I at least know it's not just the camera unless both are broke.

    The only thing I can think of is a compatibility issue with the EQ6-R mount. Maybe the negative Y direction (going down in declination) is because the wires are crossed and the tracking is trying to operate the RA motor and track the sky but I'm just guessing at this point. If you know what I can do to stop the mount from drifting, let me know.

    Thanks
     
    CrossoverManiac, Feb 20, 2020
    #1
  2. Colin Haig

    Colin Haig Staff Member

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    The core of the issue is probably the wiring of the RJ12 in the EQ6-R is flipped left-to-right, as compared to the classic mounts like the Meade LX200.
    What happens is the ground pin is being connected incorrectly to the Y-, so the mount is constantly running in that direction.
    The standard telephone style silver satin (flat) RJ12 cable is a jack-to-jack cable with the ends flipped. If you hold the modular plugs, gold fingers toward you at the top, tabs away from you, and check the color of the wiring, you'll likely see a blue wire on one end. If you have both blues on the left, you have a straight-thru cable; if they are on opposite ends, you havea a standard telephone style cable. You need the other kind.
    Also, do you have a relay box for the ST-7E ? That may be necessary as well.
     
    Colin Haig, Feb 20, 2020
    #2
  3. CrossoverManiac

    CrossoverManiac Standard User

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    I just ordered a relay box online
    Which one is the other kind - the one with the blue wires on opposing sides or the one with the blue wires on the left?

    .

    I just bought one online at Cloudy Nights as suggested by the SBIG Yahoo Group. Do I need any special adapter between the relay box and mount?
     
    CrossoverManiac, Feb 21, 2020
    #3
  4. Colin Haig

    Colin Haig Staff Member

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    On opposing sides = the standard, aka USOC RJ12 6p6c silver satin telephone cable.
    On same sides = straight through wired version

    I suggest you have a look at the manuals so you really know what is going on - and whether you need(ed) that relay box.
    We've archived them here:
    https://diffractionlimited.com/support/sbig-archives/
     
    Colin Haig, Feb 21, 2020
    #4

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