Topic Subscribe
WATCH  2 pages [ <<    <    ( 1 )     2     NEXT    >> ]3063 viewsPOST REPLY
Thunder Power RC . Mikado . Futaba-RC
. .

e-
Align T-REX 100 150 250 450 500 550 600 700 800
 >

T-REX 450
Servos Twitch
BilJac

Senior Heliman

Phoenix - AZ

A while back, my servos would twitch randomly on my Trex 450. To fix this I have replaced everything. New frame, head, tail, servos, ESC, motor, Rx, Tx and battery. The only thing left is the GY401 and 9260 tail servo. Could the gyro and/or tail servo cause the cyclic servos to twitch?

06-04-2008 Over year old.
arffy

Senior Heliman

Ny

Try different electronics placement.

06-05-2008 Over year old.
realwiz

Senior Heliman

Medina, Ohio, USA

What RX and TX did you try? You could have some metal to metal rubbing near the RX. If you went from a FM to a Spektrum and it still happens then it's most likely not an RF issue. I've gotten jittery on over charged batteries, BEC's built into speed controls aren't the best. To determine if it is the BEC. Just temporarily attach a 4 cell reciever pack to the helicopter to see if the jittering goes away. If it does try an external BEC.

06-05-2008 Over year old.
HOMEPAGE  
BilJac

Senior Heliman

Phoenix - AZ

I originally had a JR 8103 with a PCM receiver and now have a XP9303 an 2.4 ghz. I have also use multiple batteries and purchased 2 new ones to try that out but it still happens. The first esc was a quark 33A and now I have a Scorpion Commander 55A. Truely, it's an entirely new hely except for the gyro, tail servo and the blades. Could any of those 3 cause glitches?

06-07-2008 Over year old.
R38133

Key Veteran

USA

I too have problems with twitching with the scorpion and Quark ESCs. Went to the Jazz and now all is good.

06-07-2008 Over year old.
xxcysxx

Key Veteran

Baltimore, MD - USA

i haven't seen anyone mention damage servo. perhaps you should replace the twitch servos instead.

[edited]

try this, power up your heli by plugging in the battery and turn on the transmitter, and just leave the heli and transmitter sitting on the table or bench. don't apply any throttle to the motor, or have the rotor head spinning. just let it sit there stationary.
constantly stare at the cyclic servos while it is sitting on the bench for about a minute, or two. if you see any servo twitch on its own, just replace that servo. do it about two or three times to confirm that the culprit servo is indeed bad.

by the way. if you are by any chance using the castle creation 10amp bec (ie. CCBEC 10AMP bec) i advise you to unplug the castle bec from the receiver and use a separate 4.8v battery pack to analyze this.

let us know how it turn out

Tam

06-07-2008 Over year old.
dkshema

rrMaster

Cedar Rapids, IA

if you accidentally plug the servo reverse into the receiver, ie. having negative plug into the signal and signal into negative, just once, and power up the electronics. the servo sensor is damage.
WRONG. Absolutely, unequivocably, totally WRONG. Plugging the servo lead into the receiver backwards does NO damage to anything, the servo just doesn't work until you plug it in correctly.

I don't know where you heard or read that plugging a lead in reversed will kill or damage the servo, it's simply nothing more than incorrect, and you are spreading misinformation.

-----

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

06-07-2008 Over year old.
OU812

Heliman

Louisville, KY - United States

Servo Twitching

I had this problem as well a few months back! I had wrapped the servo wire around the frame to make it look better and hide the wires - wrong way to do it! It was definatley the problem! After un-wrapping everything I just hid the wires in sleeves or shrink wrap and it cleared the problem I was having! Just before this I thought it was a damaged servo because I had crashed really really good (if that's even the right thing to say)! Anyway I had replaced the gears on some of the servos and it wasn't until I unwrapped all the wires that the problem stopped? You may also try a ferite ring (magnet)?
Good Luck!

06-07-2008 Over year old.
Eagle2bravo

Veteran

Out flying somewhere

Servos twitch when they go bad.

T-rex 600n super pro , Trex 450 se, Gaui 200, Trex 500, Blade cx, . "If ya plant corn, ya get c

06-07-2008 Over year old.
xxcysxx

Key Veteran

Baltimore, MD - USA

WRONG. Absolutely, unequivocably, totally WRONG. Plugging the servo lead into the receiver backwards does NO damage to anything, the servo just doesn't work until you plug it in correctly.

I don't know where you heard or read that plugging a lead in reversed will kill or damage the servo, it's simply nothing more than incorrect, and you are spreading misinformation.
i'm just trying to help the guy troubleshoot his problem. i dint mean to accidentally spread misinformation.

though i did read somewhere a while back that plugging in the servo backward could potentially damage the servo internal sensor. not the pot though.
i couldn't remember this site or could i find any other evidence to backup my statement. so we will just see it as misinformation. i have edited my post to save the debate, and carry on with the help.

Tam

06-07-2008 Over year old.
BilJac

Senior Heliman

Phoenix - AZ

Yeah, I can't figure it out. The servos are brand new HS-56 HBs. I got these to replace some cheapos I had previously that did the same thing. I thought new servos would fix the problem but it didn't. All of my wires are outside the frame, not wrapped around it. I will try usung my CC 10 amp BEC to see if that clears things up. I will keep you posted. I have never had this happen before so something has to wrong somewhere.

06-08-2008 Over year old.
xxcysxx

Key Veteran

Baltimore, MD - USA

i had the same servo you are using on my hornet x3d a while back and it had the jitter problem. the hitec hs-65 hb.
would you try powering up the heli and transmitter to see if the servo would jitter by it self without any interaction with the transmitter. just leave the heli and transmitter sitting there, and observe the cyclic servos.
then just replace the servo that jitter.

don't use a castle creation cc 10 amp BEC to power the servos when you are observing the servos. use a separate receiver pack. if you don't have receiver pack then you can use the the bec from the speed control.

the castle bec, for some reason causes all the servo to actively buzzing noises when powered on. like as if the servos was actively correcting it self. this is when i was using jr ds285 digital servos on my mini titan. i though it was the digital servos thing, but when i connect a 4.8v receiver pack, it dint make any buzzing noise. i even tried using the bec on the speed control and it dint make the buzzing noise.

your hs-56 servos are analog, so i don't know if it will do the same, but you try it and see if it does the same.

regardless, the cc bec was working fine in flight by the way. however, i would advise against using a cc bec at all, as there are reports of failure. and when it does, it doesn't regulate.

Tam

06-08-2008 Over year old.
BilJac

Senior Heliman

Phoenix - AZ

Powered on but at 0 stick, blades not moving, the servos do not twitch. Therefore it must be some interaction with the mainshaft, motor or power through the ESC. It's just strange it did it on 2 different frames and heads on both my Quark 33A and Scorpion 55A. I will try playing with my servo wires to see if it helps. I have yet to try the ferrite rings on these servos but I did use them on the old ones and it only helped a little.

06-08-2008 Over year old.
xxcysxx

Key Veteran

Baltimore, MD - USA

okay then that eliminate the servo problem. if the servo twitch during flight while the rotor head spools. could also be glitch as well.

could you check the upper and lower main shaft bearing, the front pulley bearings. okay so basically, check any bearings that rotate from the frame to the tail. feel if there is any notchy, if the bearing feels dry and notchy, even a slight bit. just replace it.

you could also check the main blade grips bearing, but unnecessary at this point.

you could also try lubing the culprit bearings to fix the problem, then later replace the bearing at your convenient.

if possible, use an fm receiver to better trouble shoot the problem. pcm will mask the problem, so it is hard to get proper result. don't hover the model under an incandescent light, do it outside.


ps. i could say "esd", but very unlikely at this point. since you dint mention twitch from the tail. so we will leave this problem out.

Tam

06-08-2008 Over year old.
BilJac

Senior Heliman

Phoenix - AZ

I think I figured it out. It's weird since it was happening on my old frame as well but here it goes. I am using a 3DX 450 frame like the one pictured below. The twitching stopped when my hand was touching the upper metal frame piece. So I ran grounding wires between the upper to middle frame then the middle to lower frame. The metal pieces that the motor, servos and rotor attached to. I have never had grounding issius before and this doesn't make much sense to me but it seemed to work. I finally got my first flight on this thing today.

06-08-2008 Over year old.
Sar

Elite Veteran

Saugeties, NY

I had a problem with all my servo's twitching when I switched to a micro-fm reciever. When I was running PCM I had no problem. They would twitch sequentially as if the timing on the pulse train was being shifted just a tiny bit. The solution, for me, was to take the cell phone out of my pocket when I was leaning over the helicopter.

--
Jon

06-08-2008 Over year old.
HOMEPAGE  
tdearth

Heliman

Nineveh, IN - USA

Quote
--------------------------------------------------------------------------------

WRONG. Absolutely, unequivocably, totally WRONG. Plugging the servo lead into the receiver backwards does NO damage to anything, the servo just doesn't work until you plug it in correctly.

I don't know where you heard or read that plugging a lead in reversed will kill or damage the servo, it's simply nothing more than incorrect, and you are spreading misinformation.
--------------------------------------------------------------------------------


i'm just trying to help the guy troubleshoot his problem. i dint mean to accidentally spread misinformation.

though i did read somewhere a while back that plugging in the servo backward could potentially damage the servo internal sensor. not the pot though.
i couldn't remember this site or could i find any other evidence to backup my statement. so we will just see it as misinformation. i have edited my post to save the debate, and carry on with the help.

Tam
Many years ago there were some radio manufacturers that set up there wiring on the rx and servo with the pos. and neg. leads on the two outside positions with the signal wire in the middle.
With these systems if you plugged in the servo reversed you could short out the rx.

Now all manufacturers put the pos. and neg. wires beside each other with the signal on the outside . Thus reversing will do nothing except not let the servo work.

Tim

08-15-2008 Over year old.
jascat10

Heliman

Melbourne Australia

Trex 450SE Servo Twitching

The Hitec HS56 servo twitching in my case started after a nose in crash. The aileron servo was damaged. After all the damaged parts were removed I installed just the main shaft and gear drive and ran the motor to check for vibration and further damage.

I then noticed both the elevator and pitch servos both started twitching only when the motor would rev up.

I checked the servos without the motor running and the servos worked fine.

After googleing for a possible solution I was lead to this forum and read the post from xxcysxx about bearing damage.

As the main bearings were both working ok I then removed the toothed belt from the Tail drive assembly. Guess what the twitching dissappeared. Turns out the shaft on the Tail drive assembly was bent. This was only really noticeable when the whole assembly was removed from the body and spun in your hand.

Thanks xxcysxx for the solution

10-05-2008 Over year old.
Magic Hook

Senior Heliman

Naples, Florida USA

Twitching

I moved my ESC away from my receiver and it went away.

10-05-2008 Over year old.
jascat10

Heliman

Melbourne Australia

Trex 450 Servo Twitching

The servo twitching started again even after changing the rear tail drive assembly and the main bearings. The twitching stops when I removed the toothed belt of the rear tail drive assembly. I then ran the motor full throttle etc and the servo's worked fine. I reinstalled the toothed belt with a reduced amonunt of belt tension. The servos seem to be working ok but I'm covinced this could have been the problem. If would be great to know if anyone has experienced something similar. Thanks

10-06-2008 Over year old.
WATCH  2 pages [ <<    <    ( 1 )     2     NEXT    >> ]3063 viewsPOST REPLY
HeliProz . Boca Bearings . ExperienceRC
. .

e-
Align T-REX 100 150 250 450 500 550 600 700 800
 >

T-REX 450
Servos Twitch
 Print TOPIC Advertisers 

Topic Subscribe

Wednesday, August 27 - 10:13 pm - Copyright © 2000-2014 RunRyder   EMAILEnable Cookies