I Got Nothing...

Discussion in 'Radian' started by Chris Daidone, Jan 29, 2014.

  1. Chris Daidone

    Chris Daidone Member

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    I want to publically thank Andy Johnson-Laird, Shaun Stanton, and Gary Haynes for all their help both on the forum and also behind the scenes. For their wealth of knowledge, and help they provided to get my Radian issue resolved. The late night and weekend phone calls just prove there are some that are willing pull all the stops for a complete stranger, and I'm forever in your debt. This is truly a great community to be involved with.

    For the record, after all the troubleshooting, it came down to a blown roll servo. It has since been replaced and working as it should.
     
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  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Glad to hear that you got it all sorted, Chris. These aircraft and associated subsystems are quite daunting to learn -- and when they fail, you have to follow a fairly rigorous diagnostic strategy. The best hardware diagnostic strategist I ever met was a computer engineer (who, being a modest man would prefer to remain anonymous, but his name is Jesse Cable :) ), and after working with him for several weeks I realized what he was doing: "You take stuff out of the system [EDIT] from the back end of the system until the failure goes away. Then you add stuff back in until the failure comes back."

    The other strategy he taught me (which, in a way, is a variant of the above) was to start at the beginning of the system, and then work, painstakingly through the system, step by step, verifying at every point that you can, that the system is working.

    One thing that is quite hard for us with copters is that we cannot easily see whether there is DC voltage where it should be, and whether there are control pulses happening at the right places in the system. For that, IMHO, you owe yourself a treat: http://www.amazon.com/Seeedstudio-DSO-Nano-Oscilloscope-v3/dp/B00BB4ETJW
    EDIT: For the record, it was Gary Haynes who found this first. I was using a different brand and this is far superior.

    Learn to use this -- it's battery powered so you can use it on location and it can, in a heartbeat, tell you whether or not you have DC voltage where it should be, and pulses where they should be. It's the functional equivalent to a doctor's stethoscope or a nurse taking a pulse.

    The only problem I've found with this unit is that the peak-to-peak voltage measurement is not accurate, but I rarely need that.

    Hope this helps.
    (And profound thanks to Jesse Cable!)

    Andy.
     
  3. Chris Daidone

    Chris Daidone Member

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    Thanks Andy!!!
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Funny you should say that, Steve, I'm in the planning stages for the next RGG which will include a section on using a scope. The documentation for the DSO Nano is a little, errr..., sparse -- yeah, that's it, sparse. If you've used other oscilloscopes, then you can figure out how this one works, otherwise, I grant you it's more challenging.

    Did I mention that the doco is "sparse?" ;)

    Andy.
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

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    I shall set my DVR post haste. Do you have an air date yet? I assume it’ll be on the Discovery Channel? Or are you going for Pay-Per-View this time?
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Gumroad.com. You'll be able to download them without any DRM imposed on them -- I grew weary of having to hassle with DVDs and also felt bad for folks outside N. America who had to pay duty on atoms and hassle with NTSC TV Standards ("Never The Same Color"). See my confession at http://rathergoodguides.com/videos/

    Andy.
     
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