I dug this picture up from Ricks. Don't make me RE one of the servos I have.
Look in the feedhorn. See if in fact the probe snaps to the H-V positions.
A pulse from the receiver or mover tells the servo to go H or V.
The dude that tells determines probe position is the feedback potentiometer.
Think of a rotary volume control that goes scratchy or has dead spots in volume.
If the servo circuitry is looking for ~100 ohms for H and ~1250 ohms (only an ex.) for V.
As the gears spin which also rotates the feedback device (pot) and the probe is rotating in the feedhorn. And the pot has a range of 0-2500 ohms.
With the circuitry looking for a resistance match. The pot is dirty, defective......has a dead spot(s).
What happens? The servo stops or starts hunting trying to get what it takes to satisfy the circuitry.
Heaven forbid the same thing happened to an RC airplane or chopper and gave the neighbors dog a haircut!
Or kept right on going to Kansas.
Look at the notes.
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