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-   -   Servos JR 8411 always humming (https://www.rcuniverse.com/forum/rc-radios-transmitters-receivers-servos-gyros-157/3514412-servos-jr-8411-always-humming.html)

thinano 11-02-2005 12:50 PM

Servos JR 8411 always humming
Hi everybody,
First, excuse me by advance if my english is not perfect. I'm french. (don't hesitate to correct me !!...)
I've got 6 JR 8411 servos in my new plane.
When I supply the plane (it's ready to fly !!), the servos are always humming and when I touch the flight controls, I feel them a very slightly vibration.
All my servos are new (out from the box).
I have tried another receiver and another input voltage (4,8 volts). No change ...
What do you think about that ??
Is it normal ???
What do the others users of JR 8411 think about these noises and vibrations ??
Can I fly safety like that ??
Is there no risk of damage for the servos in the long term ??

Thank you by advance for your answers.


juanes1969 11-02-2005 01:05 PM

RE: Servos JR 8411 always humming
Hi, I had the same worry with the 8611 I have, but it seems that digital servos always humm, it is them always centering themselves. When you have everything in neutral position, the weight of the surface makes them humm like that. However, make sure that you have no binding in the control linkage and that the vibration is not more than that humming noise.
As I was told here in the forums, digitals always make that humming noise and there is no problem with them.
Hope this helps and someone else will probably give you a better explanation, I don`t think you have anything to worry about.

panzerd18 11-02-2005 03:45 PM

RE: Servos JR 8411 always humming
I have standard JR 539 servos. Sometimes they hum too when all controls are centered. I also wanted to know if this is normal because I am new to the hobby.

dirtybird 11-02-2005 04:29 PM

RE: Servos JR 8411 always humming
As per the JR advertisement, the JR coreless digital servos are set with 0 us deadband. This means there is no resting place so it will always be trying to find a resting spot and continue to buzz.

Spacey 11-03-2005 02:53 AM

RE: Servos JR 8411 always humming
Yea it's the day the digitals stop humming you have to be worried! LOL

A digi will always have that slight humming noise to it BUT! NOTE BUT! Take one of the servos out or disconnect the control surface completely so you just have the servo horn connected and nothing else. No pushrods nothing. Switch the servo on and listen to the humm it makes. You'll notice it's a rather low volume humm. Now take your hand and apply a very slight pressure to the servo arm and listen to the volume of the humm increase (Stop doing this as soon as possible :D). Now you'll know what to listen for when the servo is binding near the ends of the throw range. Avoid binding as far as possible! Now the servos in 3D planes will go through some strain sometimes at full throw as the mechanics of the control setup gets less efficient. We live with this but try to minimize it as much as possible. Think of a car rolling forward...doing what it's supposed to do right? Now put a brick wall in front of it...it's not going to be able to do what it's supposed to and well definitely stop working to a certain degree. You don't want this happening in any servo!

thinano 11-03-2005 11:58 AM

RE: Servos JR 8411 always humming
Thank you for your different answers,

Don't you think there is a risk of "non-reliability" for the servo (especially for the potentiometer) after a long time ??
In flight, is there no visible fluctuation in the flight path of the plane caused by these small permanent corrections ?
I'm afraid to undervalue the capacity of my reciever's battery if the servos operate permanently. Which capacity do you use for 6 servos ?


AirmanBob 11-03-2005 02:02 PM

RE: Servos JR 8411 always humming
Yep...you better get a bigger reciever battery if you want to fly more than 2 or 3 times. I'd get something like 1500mah or bigger depending on how much weight you can afford tocarry with your airplane.

Happy Landings, BOB

DMcQuinn 11-03-2005 05:58 PM

RE: Servos JR 8411 always humming
i have had trouble with the pots wearing out on my 8411 servos. I think it is a side-effect of the servo always oscillating around the neutral spot. Other lower-cost servos last for years, but the 8411 servos need new pots every year.

panzerd18 11-04-2005 02:33 AM

RE: Servos JR 8411 always humming
Can anyone tell me why my standard 539 servos also hum?

thinano 11-07-2005 11:44 AM

RE: Servos JR 8411 always humming
Hi Panzerd18,
I'll try to help you.
The JR 539 servos are Standard High Torque Servos type and normally, they don't have have to hum beacause this type of servo has a resting point (at neutral position).
First, try to disconnet all the pushrods to let the servos free of charge.
If they continue to hum when youy don't operate the transmitter, the servo (or the servos) has (have) a problem. See your dealer for after-sales service.
If they don't hum, you have surely a "stuck point" in your control rod (s).


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