Resolved AOX not working with filter wheel

Discussion in 'Guiding and Adaptive Optics - StarChaser and AO' started by Mchaser, Oct 12, 2020.

  1. Mchaser

    Mchaser Cyanogen Customer

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    Hi,

    I have a 16803, 7 position wheel, off axis guider and the AOX. All had been working perfectly. Recently the filter wheel stopped turning. Bill diagnosed a bad circuit board and replaced it. All components tested fine on his test bench. At the observatory, the AOX refused to move. This was observed in TSX, maxim and ccdops.

    However, when I unplugged the filter wheel from the AOX, the AO works perfectly. On all three software packages. The filter wheel works regardless of the AO status.

    This may be relevent, or just a tangent. Originally I used the SB power cables. I found that running the camera, cooler, filter wheel, guider and AO cuased errors. Another thread expressed the opinion that the through the mount SB cabling is too narrow a gauge to support the electric load. Sure enough, that problem was eliminated by using SBIG supplied power from the wall to the camera.

    I have only one thought, other than to see if Bill can diagnose something else. My guess is that the power supply might be going bad, causing the AO to fail to move.

    Any thoughts from the group? Bill suggested I ask.

    Thank you,

    Mike
     
  2. Colin Haig

    Colin Haig Staff Member

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    Mike, please describe the cabling order.
    e.g.
    STX Camera I2C Aux connection -> FW I2C cable
    FW2 I2C Out ---> AO-X I2c In
     
  3. Mchaser

    Mchaser Cyanogen Customer

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    Hi Colin,

    Cabling goes like this. Camera I2C aux to AO I2C in,
    Filter wheel is hardwired to AO I2C out.
    Guider is plugged into camera remote guide head.
     
  4. Colin Haig

    Colin Haig Staff Member

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    What happens if you power it all off, and try the wiring order I describe above? (I'm not sure if your cables will be long enough).
    Looping in @Bill in case he has an idea.
     
  5. Mchaser

    Mchaser Cyanogen Customer

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    The camera I2C aux is male. The I2C cable has a male and female end. By plugging the female into the male camera port leaves me a male I2C end. The I2C port on the wheel is male. I would need a gender changer to plug that in. The filter wheel RS232 port is female so I could plug into there.

    The white cable hardwired to the filter wheel is a serial female p,lug. So it can only go into the AO I2C out, or into the camera I2C aux.

    If it's easier, I can send photos, but I'm guessing you know what all this stuff looks like! Or I can talk it out.

    Thanks,

    Mike
     
  6. Doug

    Doug Staff Member

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    It shouldn't really matter what order the cables are connected in. The I2C is a common bus shared by all attached peripherals - they are connected in parallel.

    Perhaps you have a bad cable?
     
  7. Mchaser

    Mchaser Cyanogen Customer

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    Hi Doug,

    Since the AO works when the filter wheel is excluded, would that suggest a bad filter wheel cable?

    Also, if they are all in parallel, why would a bad filter wheel cable cause the AO to fail?
     
  8. Doug

    Doug Staff Member

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    Maybe you should pop the lid off the filter wheel and look at the cable end that attaches to the circuit board.

    Also check the power LEDs on the camera - low input voltage could also cause trouble.
     
  9. Mchaser

    Mchaser Cyanogen Customer

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    Good points. I'll check those out.
     
  10. Mchaser

    Mchaser Cyanogen Customer

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    Case solved. At Colin's suggestion I removed the power cable from the thru-the-mount path and ran it externally. Works like a champ. Thanks for all the help!

    Mike
     
  11. Colin Haig

    Colin Haig Staff Member

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    Glad to hear it.
     

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