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Continous Rotation Servo Mod - Adjustable Method

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Picture of Continous Rotation Servo Mod - Adjustable Method
5k 25t pot digiket.JPG
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I know there are a lot of methods for doing this but I was unhappy with the other methods.  Servos have 4 basic parts motor, gear train, controller board, and poteniometer(pot). The two things we need to modify are the gear train and the pot.  What I will do different is by using a different pot that allows for adjustment in case your servo doesn't spin the same speed in either direction or needs to match speeds with another servo.  The pot im using is a 5k Ohm, 10% tolerance, 25 Turn trough hole trim pot from Digikey.  I'm also assuming that you know the basics on how a servo motor work and if not see the pdf below.  

5k 25Turn Pot - Digikey
http://www.digikey.com/product-search/en?x=12&y=16&lang=en&site=us&KeyWords=A105772-ND

My Specific Servo
http://www.ebay.com/itm/MG996R-Torque-Digita-RC-Metal-Gear-Servo-FOR-RC-Helicopter-CAR-Boat-/390528100232?pt=US_Radio_Control_Control_Line&hash=item5aed49e788
Futaba compatibile arms/spline shaft

Tools/Materials Used:
#1 Phillips Screwdriver
Grease - General Purpose
Needle File Set
Heatshrink
Soldering Iron
Hot Glue Gun
Small Gauge wire
Wire Strippers
Drill 
etc.



Step 1: Remove Existing Pot

Picture of Remove Existing Pot
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A) Remove the four screws on the rear cover.

B) The circuit board and motor should easily slide out, the motor may require some jiggling.

C) With my servo there is a screw holding in the pot that needs to be removed.  Your pot may be directly soldered to the board as in the fifth picture.

D) Now unsolder the pot's leads from the circuit board or from the pot itself.
 
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Gelfling61 year ago
The Futaba S3004 servo is a very similar design, especially the placement of the original POT... I've converted them, but "Z"-folded the POT strips, and fed the tip through the side of the case.. Still, a 10-turn POT is best for super fine-tuning! Great mod!