Help! Servo jitters

mayan

Legendary member
Ok so am puzzled I can’t understand why this is happening.



I have already advised over PM to try figure it out and did a bit of checking. So here is what I already tried and what I am still to try.

Hai-Lee said:
Having said that I will ask if you can replicate the issue using a servo tester?

No. I don't seem to be able to replicate the issue using a servo tester.

Hai-Lee said:
If you just swap the aileron servo connection and the rudder servo connection on the Rx does the problem stay with the rudder servo or does in transfer to the aileron servos?

If I connect the servo to the ailerons channel the issue stays with the rudder.

Hai-Lee said:
Does it do the same thing with the motor leads disconnected from the ESC?

Yes the issue stays the same.

Hai-Lee said:
Does it still do the same thing using an alternate ESC? (No need to have motor connected)!

Hard for me to check because the other ESC that has the same banna connecters (3.5mm) is also giving me an issue. It's the one used in the Tedge which has a similar issue with the ailerons. So using a different ESC that also gives an issue won't give me a good indication.

Hai-Lee said:
Has the ESC/Motor ever been crashed?

On the Mini Edge yes on the Tedge no. On the the Tedge the servos, motor and ESC are all new.

Hai-Lee said:
Have you ever got your Tx wet?

Not that I recall but the issue hasn't happened with the TT or SpiTTT. The only difference between these models and the others where the issue occurs, is the 3.5mm banna connectors.

Hai-Lee said:
Does it still do it with a different motor fitted?

Won't make a difference if the problem occurs even without the motor connected.

Still puzzled here so I want to open this up to everybody someone might have another idea or learn from it.

I still need to try to power the Rx using dry cells to eliminate the BEC failure.

Any other ideas why this happens?
 

Arcfyre

Elite member
Hey buddy. I have this happen to me too when I'm standing too close to the plane. For me it's always the elevator servo though, lol. Usually by giving a small control input it goes away, and I have never (to my knowledge) had it happen in flight. I always just assumed it was a feedback error or something, like what happens when you hold a microphone too close to the speaker it's broadcasting out of.
 

Merv

Site Moderator
Staff member
Are the gears in the servo is worn out, too much slop, backlash. Metal gear servos will wear out much quicker than others.
 

Paracodespoder

Elite member
I had the same issue with my ft edge, didn’t cause any flight problems. I thought it was just because the control surface was so large, still don’t know what it was.
 

Piotrsko

Master member
You have what sounds like 60hz buzz which indicates reception of a "Polluting" signal at some odd harmonic. In my experience it usually affects only 1 receiver channel (usually #1) where the servo is hunting to keep up with a signal. Also known as zero beating. It might affect #5 or 6, ive never flown more than 3 channels.
Straight crystal does this when you get too close or have cheap imported fluorescent lights on some frequencies. Separate the radio/transmitter a couple of feet, go outside. I've never had it affect a flight. 72.4 mhz is famous for this due to police/fire bands, 75.5 ditto
 

Wildthing

Legendary member
One of my 3D planes the elevator servo did it, I could sit there and watch it jitter, touch the control surface and it would stop or when I moved the stick. Never affected it in flight at all. I think with the weight of the large surface plus the control rod was mounted on the farthest hole on the servo arm the servo itself had a hard time keeping itself centered. I changed out the servo and even rx and still had the same jitter.
 

mayan

Legendary member
Thanks for all the inputs at least now I know that I am not alone. I also haven’t had issues with this during flight but still launching a plane that way is kind of scary you all must admit.
 

Bricks

Master member
I have run into this when the BEC could not keep up with the servos, in other words the servos were trying to pull more amps then the BEC could put out. Many times people blame this on the receiver and ultimately leads to a brown out of the receiver so they blame the radio system..
 

Wildthing

Legendary member
It’s a 40A that I am using can it be that the ESC can’t hold up?

Take a close look at your esc, it will tell you how many amps the BEC is rated at. Most esc's are only 2 or 3 amps , 3 or 4 servos you are usually good for but anymore it can't hold up. Then you install an external bec that is rated say for 5 or 6 amps.
 

Hai-Lee

Old and Bold RC PILOT
What drives me nuts is that on some planes using the same equipment it just doesn’t happen.
Just a recommendation to possibly help with the resolution of your problem or issue!

You could post all of the things that you have tried to resolve the issue without effect or had a minor effect so that you do not get many suggestions all very similar. Like most problem solving from the other side of the world the more info the better and this should include failed measures as well.

Just a suggestion!

Have fun!
 

mayan

Legendary member
Some great suggestions here. Like @Hai-Lee recommended, I’ll find time to post all of what I have tried so far what worked and what not including the lastest suggestions received and that might help all of us figure this out.

More later...
 

bracesport

Legendary member
@mayan - as you know I have experienced some flutter lately and have worked through most of the options to find the root cause - at the moment I believe it is the servo or the servo plug - when I moved the servos around the flutter continued - when I removed the servo the flutter stopped, and when I replaced the servo the flutter stopped.

These tests were done with control rods both on and off, and I added an extension cable as another test (same result).

I have not checked the plug or opened up the servo just yet - they are new so I am getting a replacement and that should show definitively its a crook servo (fingers crossed).

As you say other planes with the same Tx and Rx are fine so it is unlikely the gear!