Splicing a servo wire

Tutorials > Splicing a servo wire


Sometimes servo wires aren't quite long enough. Extensions are one option; In my opinion, however, it's better to add length to the wire by splicing. There's less resistance and the possibility of a failure at an inaccessible connection is eliminated.

Note: I am not an electronics technician and what I know about soldering I learned through research and practice. I'm not claiming the methods I've used here are the only ones or even the best ones - but they work for me.

1. Gather the soldering equipment - iron (or station), solder, flux and clamp:

Soldering tools and supplies

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2. Make sure to dampen your cleaning sponge:

Dampened sponge

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3. Don't forget the wire strippers:

Wire strippers

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4. Take your brand new servo out of the box, take a deep breath and cut the wires. I like to do it somewhere in the middle so I don't have to deal with short ends:

Cut closeup

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5. Take up the extra length to be spliced in and separate the insulated wires at one end. I use my fingers so as not to nick the insulation:

Strands separated

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6. Strip a bit of insulation from the wires. I like about 5 mm (3/16"):

Stripping the insulation

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7. Once all the wires are stripped, twist the strands of each one:

Strands twisted

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8. Dip each of the wire ends into the flux:

Flux on the wires

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9. Time to tin the tips. Conventional wisdom dictates that you should heat the wires with the iron and apply the solder to the heated wire. However, with my soldering station set to 370 degrees C (700 degrees F) a blob of solder on the tip of the iron wicks instantly into the flux-covered wires:

Tinning the tips

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10. Tin all of the wires:

Tips tinned

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11. Go back to step 4 and do the other end of the splice, then repeat the procedure for the cut ends of the servo wire. You'll be stripping, twisting, fluxing and tinning twelve tips in all:

Both ends tinned

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12. Before attaching any wires, slide on some heat shrink tubing for the individual joints:

Heat shrink for individual wires

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13. Slip on a larger piece of tubing to cover the bundle of wires:

Heat shrink for the bundle

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14. Arrange a wire from the extension splice so that it is stationary and in contact with the corresponding servo wire. I like to make my first joints from the splice to the section of cut wire with the connector attached so that the servo is out of the way as long as possible:

Wires in the clamp, touching

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15. Ensure the wires are touching, and apply the iron to the joint:

About to splice

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16. Solder will flow between the wires to create a joint. Out of habit I join the negative wire first:

Negative wire spliced

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17. Join the second pair of wires:

Positive wire spliced

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18. Finish the connection by joining the third pair of wires:

Signal wire spliced

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19. Take up your heat source of choice to shrink the tubing:

Time for the heat gun

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20. Arrange the narrow tubing over the individual wires:

Individual heat shrink in place

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21. Shrink the tubing for the individual wires:

Shrunk

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22. Slide the larger tube over the individual wires and shrink it:

Bundle shrunk

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23. Go back to step 12 and repeat the process to join the other end of the extension splice to the servo:

Both splices done - another look

All done. Be sure to test the servo connection and direction before taking to the air.

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