Motors Emit High Pitch Whine

Hello all,

We are totally new to VEX (but not to engineering) and just began toying with a new starter kit.

All was well until I decided to experiment with a servo motor. Since then, every time we plug in a motor, it begins to emit a high-pitched whine. It does rotate and respond correctly to commands. Whine is dependent upon the transmitter being on. We have reset the transmitter config, but this has not helped.

I am sure that this is simple. Any assistance would be appreciated.

Looking forward to collaborating with you all.


first a servo is differant from a motor a servo only turns about 90 degrees and for the whining sound all the motors do that u just have to adjust the trim untill they are silent

Thank you for quick response. Adjusting trim did correct problem.

It is interesting that we did not experience this with the first motor we worked with. The introduction of the servo was just a red-herring.

IIRC, the Motors (and Servos) will all vary a little, due to Manufacturing Differences. What this means is that two motors at the same “level” will run at different speeds.

Your Motor that is “whining”, if you move the Joy Stick up or down a little, does the “whining” stop??

Set your Bot up on a Block(s), so the Wheels can turn freely and the Bot won’t drive around on the floor.
Setup your Square Bot for 4 WD (jumper on Input #15 for Tank Mode 23), and place the “whining” motor on the Left (Motor Port #3 for Tank Mode 23) and another “non-whining” in the Rear Left (Motor Port #8 for Tank Mode 23) (or Both on the Right Side if that is easer).

Use the Left (or Right) Joy Stick… Press it Slowly up, then return to the Neutral Position. Press it Slowly Down, then return to the Neutral Position.

You will most likly find that the Motors start turnning at different times, and turn different speeds for the same Joy Stick possition.

The Motor or Servo can be different from device to device… Adjustments must sometimes be made for different units.


Quick experimentation suggests that this is indeed the case. Thanks for the info.


Not a problem. There is quite a bit to learn about these little “kits”…