HiTEC HS-645MG servo before modification
no soldering, no cutting, no part replacements…..
!!! the modification is reversible (if you keep all the parts and don't damage anything, of course)
* the gear with the pin will come off together with the second gear shown on the piece of paper.
* it should come out very easily, no force needed
* the hole should be big enough for the three potentiometer wires to pass comfortably when you close back the casing.
* hold the pin with a pair of locking pliers. gently hit the top of the gear with a hammer to push the pin out. be careful not to damage the gear.
* you can save the pin, in case you want to modify the servo back to normal
* make sure to put them back all the way so they can move
* make sure the potentiometer's wires are not caught or pressed
* connect the servo to a microcontroller and turn the potentiometer until you find a position where the servo doesn't turn. this will be you 90degrees.
* any value bigger than 90 (but smaller than 180) will make the servo spin clockwise. accordingly, values between 0 and 89 will make it spin counterclockwise. the bigger the difference between 90 and the given value, the faster it will turn.