U Can Do 46 - Jittering Servos
 

I have just completed my UCD 46 and I have a lot of jittering when I do a range check.

The antenna is outside of the fuse, it goes to the vertical fin. I replaced the receiver, the quartz but the pb. remains. Does someone got this jittering pb. too? If yes how did you fix it? Could it be due to the long tail servo leads?

What Any suggestion.

Thanks, Chris.

RE: U Can Do 46 - Jittering Servos
 

Do the servos jitter when the engine is running? If not then I would say that the servos are bad. I have the Ucan do 60 and they jittered only after about 100 flights and then it was due to I neede to replace it. Now it is fine. JIm

RE: U Can Do 46 - Jittering Servos
 

What brand servos are they? What voltage battery pack?

RE: U Can Do 46 - Jittering Servos
 

How many servos jitter ?
At what distance does it start or stop ?

RE: U Can Do 46 - Jittering Servos
 

Had the same problem when I put in a 6 volt pack, went back to the 4.8 no more problems. Just what happenbed to me. BTW my antenna is inside, running back to the tail by the servo leads, has been working well.(damm snow shut mw down).

RE: U Can Do 46 - Jittering Servos
 

being indors too close to a TV (on or off does not matter... the servos can jump all over the place.

Being too close to a chain link fence or other grid of metal can give all kinds of strange results to a range check (one guy gave up on a TX antenna down check at 300 yds... still had good ressonse. turned out the rebar under him and the model was tuned to his frequency. From the days of AM on that one.)

try to eliminate potential external influences. They can drive you nuts.

RE: U Can Do 46 - Jittering Servos
 

There are many causes and most were stated above! Servo type? Depending on the type, going to a 6v pack will cure it. Also increase your amp rating on the pack. 1500+ should do the trick. If your leads are long(24" or more) then try heating the leads and twisting them into a spiral. This prevents noise from traveling. You could also install a noise trap(ferrus ring). It could be location, tx battery pack, metal to metal hookups, ...etc.

RE: U Can Do 46 - Jittering Servos
 

I had the same problem once and all I did was disconect the leads and plug them back in about 15 times each I guess it just makes the contacts better.

Darin

RE: U Can Do 46 - Jittering Servos
 

Look for metal to metal vibration. Lost a spad due to loose screw. Also sometimes off a hot charge the servos will be a bit jumpy till the voltage drops a bit.

RE: U Can Do 46 - Jittering Servos
 

First, thanks for your advises.
My servos are 5 Futaba (non digital) and 1 Hobbico, they all jitter. Battery is 4.8V, 1100mAh
Sometimes I can be at 100ft and it is fine and the next time they jitter when I am a few feet away :(

- I thought to a local interference, then I turned on (at the same time) the RX of my helicopter which is on the same channel, I had no jitter on the chopper.
- I also tried with the Rx hanging out of the fuse -> Same pb.

I will twist the lead and check if this makes any difference.

Thanks, Chris.

RE: U Can Do 46 - Jittering Servos
 

Just for fun try another switch, sometimes they do not contact right, I have had a problem or two with them?

RE: U Can Do 46 - Jittering Servos
 

Also, disconnect the hobbico servo and check it. I had some hitecs that didnt like servo boosters hooked into them. Also if you have extensions in the tail it might benefit you to go to the heavier guage wire!
On the subject of twisting, you need to seperate the wires(if its flat!) and then warm and twist. Typically this will keep out noise up to 36" of wire length(coupled with a higher amperage battery!)

RE: U Can Do 46 - Jittering Servos
 

Plug in one servo at a time only, and range check. Also try plugging the battery directly into the rx. This should help determine the cause.

RE: U Can Do 46 - Jittering Servos
 

I have already tried the "one servo at a time" thing -> No change
I will try to plug the battery directly to the Rx and also another switch.

Thanks, Chris.

RE: U Can Do 46 - Jittering Servos
 

It looks like the next step is to try a different receiver.

RE: U Can Do 46 - Jittering Servos
 

I already tried a different Rx (fuatba R127...)

Chris.

RE: U Can Do 46 - Jittering Servos
 

Has that RX been through a crash since it passed a range check?[:-] the recievers CAN be damaged inside and have no visible damage ti the case. They can have a cracked crystal... cracked solder joints... damagec resistors... al kinds of things can get broken in there and you won't see a thing.

Try your RX out of the heli in the fixed wing plane. If swapping RX's makes the fixed wing work and the heli have the jitters, you found your problem.
******

well... timing... someone else was posting while i was writing :eek: