What would cause a steering servo to vibrate fast back and forth when I turn the battery on? I have used two different batteries that were fully charged. Servo is fairly new; Protec 130.

Curious myself. Purchased a Used Radiopost servo a little while ago in the sale section here. Just recently installed it (was gonna put it in my pit box for a backup but decided to install it) and as soon as it's powered on it vibrates nonstop. Wheels centered or not, even with the vehicle off the ground. Have yet to get it on the track but wondering if it has one foot in the coffin already. Haven't seen another Radiopost servo do this. They're always one of the quietest servos out there. Only running 6.4 volts to the servo. Tried raising and lowering the voltage with no change.

Have you tried the servo with a different radio/receiver?

Still using the same Airtronics MT-4 SSR 2.4 GHz Radio System w/RX-461 FH4T 4-Channel Receiver that I have been using all last year. This is a brand new Xray XB8 that has yet to even have the motor started! Tried both my LiFe and LiPo batteries. Throttle servo works fine. I am thinking the same thing as King Dork; one foot in the grave. Time for a new one. I just hate to spend $100.00 until I know for sure. I have not had good luck with ProTec servos. Should have bought a Hitec HS-7955TH to start with.

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Are you able to change the servo mode on that radio? Might be some incompatibility. I destroyed an analog servo once when I switched models on my radio and didn't realize the transmission mode doesn't change unless you turn it off and on again. It basically hummed itself to death.

I know the this servo is digital. But maybe Airtronics super high frequency isn't compatible.

How much is it vibrating? I know this is a hard thing to describe.

From page 55 in the MT4 instruction book use the SSR mode for Airtronics SRG type servos and the SHR mode for all digital servos. set your servo for SHR mode or normal and this should work if not you have another issue with your RX. Michael

I looked at the settings on the radio for the servo and they were OK. Thanks for the advice. I guess I will just replace the servo. I don't know what else to do.

I had the same issue with the Protek 130SS. It's a common fault. Amain accepted it back and exchanged it for a new one at no cost.

Thanks for the tip! I will start the return process. Did they require as receipt?
I have a new HiTec on order. I will use the Protek as a spare.

I just started having same problem with steering servo on my tmaxx 3.3 . this is stock traxxas 2018 servo and using transmitter/receiver that came with truck. Servo just started vibrating with no warning. Any ideas?

I replaced the servo with a new one and all is fine.

No they didn't need a receipt as I bought it on their website and all the records they needed. Exchanged it without any issue. The replacement has been fine ever since.

It's often the first plastic gear is worn and the play in the gear causes the shuddering when not under load. Usually works fine when driving but has a little bit of play due to the gear.