I have JR 811 digitals and on a 5 cell nimh they twitch worse than I do after a pot of coffee. I had to disconnect the rudder while I dialed in the throttle linkage on my new EF Edge 540 because it starts oscillating so bad. I am going to get a 5.4 v regulator and start using a lipo rx pack, but will a 5 cell pack cause any damage from the twitching?

OMG! It says JR on it! Simple as that! ....... No seriously just kidding, I fly 99% JR equipment. I saw the same thing yesterday on a katana at our field. The rudder would look like it is shivering or well gettin cold and shaking when there is no load on it. Didn't do anything in the air because it seemed like as soon as you put your finger on it it would stop. I would also like to know what is causing this.

There are a couple threads on this subject in the JR tech forum. I have these servo's too, and they do "chirp" a lot, but I don't get any noticable movement on the control surfaces they are assigned to unless I am in my garage around a metal bench.

Best I can remember, the folks at JR said that the chirping was the servo constantly finding center. Just as others have said, when I put a load on one (stick movement) the chirping stops and the works fine. If I move out into the yard or am at the field (i.e. not around all the metal stuff in my garage) the chirpping all but stops.

Just my .00000002 worth.

Thanks BB, what voltage are you running? I have the twitching and rudder oscillation with the JR 811's in both my Funtana 40 and my new EF Edge, any location. The rudder oscillation stops when the engine starts, but it is seriously annoying. I might have to run an analog on my rudder.

I've run them both on 4.8 NiCad and 6.0 Nimh.

I have read on several thread that the Jr 811 with the 770 rx have that problem also a unregulated 6.0 pack wll jitter with a hot rx pack I read somewhere its because a freash packs voltage is higer than 6 volts I use to let mine set for a few min. on and working the surfaces and it would stop as the voltage came down and never a jit after the first flight or two made me nervous tho heh

I am running 4 of them (digital 811's) on my Extreme Flight Edge 540 with a 1400 mah 4.8v NiMH battery. I get some jitter but as soon as I put even the slightest amount of pressure on the control surface it stops. I can just touch the control surface with my fingertip and it ceases. I have just over 5 gallons of fuel through my Edge and never had a glitch in the air. I have 4 more 811's that I am planning to put in my OMP Katana kit. I am very happy with them.

Yep, same here, JR 811's getting mighty shaky at times, but never any trouble in flight. But for about the same money, I think I may like the Futaba 9001 on 6 volts better.

I have seen this problem and it isnt "chirping" or "centering", it a sHaKiNg with almost a growl from the servo. Once the surface is moved, it stops and if you bump the surface again it begins again.

I have seen this years ago on my super old (1990ish) JR coreless. You would have thought they would have fixed this problem by now.

Thanks for the replys everyone. The twitching went way down as the 6 v pack ran down a bit, but I still bought a Hitec 625mg today to put on the rudder. For whatever reason the rudder servo twiches at the natural frequency of the rudder system and it starts oscillating like crazy. I posted in a thread about the same thing in the JR support forum, and the reply is that it has to do with some play in the 811's gears, combined with a powerful centering force.

I had this same problem with only one of my 811. Here is how I fixed it. As we all know is trying to find center. since theres really know load on it, it keeps jumping back and forth.

so what I done, Its on my sledge's elevator. so I tightened my clevis up on my control rod, and put the servo arm back perpendicular to the fuselage, where is suppose to go. No my elevator is pointing down a little bit but my servo is still centered. then I used subtrim on my JR8103 to bring my elevator back to level. that solved my problem.

The way I figure it works is with the control rod being shorten than needed it, the servo is at its center with having a little down elevator but there won't be a load on the servo. but when you add the subtrim on the radio it makes the servo work again, with the up elevator putting a load on the servo, making the oscillation stop.

I am running a 720mh NimH 6volt back and JR R700 RX
about 4gallons of fuel thru it so far and no problems yet.