Talion Servo horn not centered.

K29er

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The servo horn does not sit centered when trimed to 0. Can I take the servo apart and set the gears to make the horn mount center or will it always sit half a spline off.
 

WoodiE

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@K29er you're better off setting the trim to 0, removing the servo horn and then trying to place it as close to center as you can then use trim to make any fine tune adjustments if needed.
 

K29er

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I have pulled the horn off and it will not mount center. The trim is adjusted 50% or more. I have never seen a servo horn mount so far off center. Without adjusted trim the servo hits the etc at full travel.
 

K29er

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This is what I am going to try. Different servo but same idea.

From " Rc groups.com"

"first you need to make sure the servo is in the neutral position.remove the servo arm by taking the screw in the center out and pull the arm off. plug it into the receiver, turn on transmitter(controls centered) and connect the receiver battery. the servo will go to neutral. remove battery and disconnect servo.

take the 4 screws on the servo case out and open the front. you will see 5 (6?) gears.note that the one that connects to the external servo arm has 2 ribs in a V shape.

looking at this gear you can see that the teeth on the raised part of the gear are relatively coarse.however the rest of the gear train is very
"fine grained" and although you can only get within a few degrees if you only rotate the final gear or the servo arm, if you adjust the relationships in the rest of the gear train you can get the arm very close to 90 degrees.

pop the final gear off (V ribbed). be careful with the rest of the gear train because 2 of the gears are tiny and easily lost.

now lift up and rotate the gear under the final one one or two teeth then put the final gear back on.

the V on the final gear should be, as you look at the servo from the front, upside down ( vertex pointing to top of servo) .

imagine a vertial line bisecting the V angle, set the gear so that those
ribs form an equal angle on both sides of the vertical.

put the servo arm on the final gear and observe what you did.

keep adjusting the relationship of the gears until the arm is exactly at 90 degrees to a vertical. you will know you have achieved this when those rib/vert angles (above) are equal.

note that in removing/assembling the gear train as you adjust it
you might move the servo motor out of neutral position. put the front of the case back on and then the servo arm and holding/squeezing the case together re-initialize the servo as above. if it moves then you rotated the motor while working . do the above again until it doesn't move on initialization, being more careful. replace the case front and the screws.
reattach arm which should now be perpendicular to the case.

using this method i have all the servos on my 2 birds perfectly adjusted
without a computer radio or radio-side trimming .

i have to emphasize that this really works and takes all of 2-5 minutess/servo."
 

K29er

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Lol. Well that is not the way to get the servo centered. I did get it center by moving the sensor/potentiometer. If the horn is mounted 90° to the servo it sits right so the servo was built right but the number of splines won't let it sit center when installed parallel the the servo. Removing the potentiometer and flattening the alignment tab alows it to be adjusted till the horn is center with trim at 0. The problem with using trim to center a servo so far off center is it does not a just end points. This causes the servo to bend into the esc putting it a 100% load constantly when turned in that direction. It also won't turn one direction very well.
 

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