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Autopilot Pitch Servo Installation

WingedFrog

WingedFrog

Well Known Member
You could as well call this "A bad day at the workshop""
I was working on the installation of the Autopilot Pitch Servo, a difficult to reach area with lots of challenges to pass your hands as well as the parts. I was practically finished, just tying the Molex plugs and Noice filter to the housing of the servo when I heard a click... The connection of the wires to the noice filter had broken under stress.
Here is the victim (I am not considering myself as a victim, just the perpetrator!):
http://3.bp.blogspot.com/-rEOwHNmzk7k/UKuZFQ8MCwI/AAAAAAAAA8o/sYoBybRumeY/s1600/100_3471.JPG
Here is the victim lying by the instruction's drawing that caused its demise:
http://2.bp.blogspot.com/-AueSYIm0R-M/UKuYKMQSkDI/AAAAAAAAA8g/kzPNsaRxu70/s1600/100_3470.JPG
I have orderd a new filter but I fear the same will happen. Reason: the fastening of both the filter and the Molex plug to the servo housing with one big tie-wrap seems questionable to me. If you want these items to be secured, the pressure caused by the tie-wrap will cause stress to the filter casing which is just a chemical capacitor.
Any suggestion?
 
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A suggestion. Add another piece of heatshrink that covers the capacitor and also covers an inch of the wiring to provide some strain relief.
 
Experimenting on the damage filter, I found that it is possible to shape the outgoing wires to match the curve shown on the drawing. This shape will not come naturally through tension which is why mine snapped. I am still looking for material to provide cushion under the tie-wrap. I am afraid the heat shrink proposed by Marty will not be enough of a cushion. It would help if I had an idea on how hot the servo housing can get under constant operation to select the appropriate material.
 
Perhaps you could carve/shape a small piece of stiff foam the size of the filter, drill a hole in the center to pass the wires through and heat shrink it in place as a strain relief? Something that keeps that portion from bending will be of value, I'm certain.
 
One suggestion. That's $50 at Van's, and @1.29 at Radio Shack. You already have the wires w/lug and terminals.
 
After receiving a new filter, I decided to go with two tie wraps rather than just one. The main advantage is that the tie-wrap used to secure the capacitor of the filter can be tied with less tension than the one securing the plug. In addition you don't need to juggle three things together during installation. Here is the result:
http://4.bp.blogspot.com/-p-zprrpyc74/ULFjb7ffysI/AAAAAAAAA9A/5M6QOqYCkoQ/s1600/100_3472.JPG
I also added a third smaller tie wrap (visible on the picture) to secure the plug.
 
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