Hitec servo issue?
 

I have some hitec servos and they make this awful buzzing sound and get really hot because of it. What is going on. Thank you for the feedback in advance.

Makes noise lock to lock? Ck your EPA. Noise at neutral? Steering Bind, Linkage or knuckles.

It's noisy at center and during steering, epa is set proper. No binding either. Running Futaba radio.

Disassemble servo, clean gear and relube. Grease probably harden. If that doesn't work, purchase new servo or upgrade. Still noisy when you remove the Horn?

Send it in for service.

Thank you and yes

It sounds like you have digital servos, which will make a digital buzzing sound due to the circuit always trying to maintain position. A couple of questions to help us help you.

1. What servo model is it?

2. Are both servos doing the same thing? I ask this because to have 2 servos "fail" in the same manner is very unlikely, which would then lead us to look more in to the installation and powering of the servo.

3. What are you powering the servo with?

axial/castle ae2 Esc with 2s lipo. Also tested with a tekin rsx Esc as well

Is this a crawler? Asking because of your esc use.. If it's a crawler, you might need a external bec, not to mention a 7955tg

This is in a crawler but this is happening in bench test under no load and also in the crawler under load.

Ok, we have a little more information to work with. All three servos that you mention are analog servos, so the noise you are hearing would be more of a growling noise than a digital buzz. Analog servos will only ever growl when there is a constant load on the servo. You will want to remove the horn from the servo and check the steering linkage on your truck and make sure that it is free from binding. Keep in mind, that because the vehicle is a crawler, there will be a load on the servo while driving, so expect some noise, and a little bit of heat build up due to the load and the fact that there is very little air flow on the servo.

I will say again this is happening both under load and without load. There is no binding on the steering. I would suspect some noise like a savox but not like this. This is constant. It gets extremely hot as well pushing 200degrees.

If you feel you have checked all that you can check, then the next step would be to send the servos into us for examination.

Thanks! So I tried a different receiver switched it to analog and the 965 seemed to work with no humming under load and no load. The 945 still hummed but if I turned it to full left and right and then held it then let it return to center it would stop briefly. And the same with the 645. Someone had mentioned the grease hardening would this be the culprit and a break down of each and relube possibly remedy the problem?

Our grease is not lithium based, and should not harden unless the servos are extremely old. It's not that hard to check the gears, so i guess it couldn't hurt to check.