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Re-soldering leads in 8700G servo

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Old 05-23-2004, 11:39 PM
  #1  
marked23
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Default Re-soldering leads in 8700G servo

My tailboom completely busted off in today's crash. It pulled the leads clear out of my 8700G servo. It was a totally clean pull and the servo is otherwise undamaged.

So I cracked open the servo to re-attach the leads, and noticed that there is a flexible glue substance covering the pc-board. What is the solvent to remove this glue?

Also, all the wires yanked off in such a way as to leave no indication of which one goes where. In my diagram below, did I get it right?

Code:
 +--------------+
 |              |
 |              |   Bottom View of 8700G Servo
 |              |
 |    Motor     |
 |              |
 |              |
 |              |
 |              |
 +--------------+
 | +-+        O |<---Orange
 |++-+          |
 |++            |
 |    O  <--Red |
 |  +-+         |
 |  | |         |
 |  +-+         |
 |    O <-Brown |
 +-----+  +-----+
       |  |      
       |  |
Thanks Danny,

-Mark
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Old 05-24-2004, 10:23 AM
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Default RE: Re-soldering leads in 8700G servo

Due to the potential for many possible problems that could result in a failure and loss of a heli, I would recommend sending the servo in for repair.
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Old 05-25-2004, 01:54 PM
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Default RE: Re-soldering leads in 8700G servo

Thanks for the advice Danny. Under any other circumstance, I wouldn't hesitate to send it in, but it's just the leads. In spite of the fact that the boom was busted off, the tail-rotor pitch mechanism was enitrely unbroken and unbent. The tail servo was still on-center even.

I soldered the leads back-on this morning and gave it a try. It works like new. I inspected the gears and will give it a thorough stress test before puting it back into service.

BTW, for those tempted to try this at home, my diagram above appears to be correct. However, there are two points just above the "red" pad where you are likely to create an accidental solder bridge while working on the "red" pad. A bridge between the red pad and the point on the right will create a dead short between + & -. Test for non-continuity between the red and brown pads before plugging it into your battery, or it will short and may melt something. Also, slip about 1/8th inch of shrink tube onto each of the wires before soldering. The lead wire insulaton can't take the heat. Keep the heat shrink out of the way while soldering, then slide it up to the end and shrink-it-up to cover any bare part of the wire. One more thing: the glue is there to keep the wires from pulling out...like they did. Re-apply some rubber-cement, silicone or other flexible, non-conductive, removable glue to keep things in place. I would suggest letting the glue dry before putting the cover back on.


-Mark
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