Servo acting crazy

Servo acting crazy

Post by sucker punc » Thu, 05 Apr 2001 12:38:27



my throttle servo is acting wierd. When the car's power and the radio are
both on, it erractically pulses back and forth. It's doing this at such an
amount as to make the car unsafe, as the throttle linkage moves far enough to
go halfway to WOT.

any ideas? batteries maybe? I would have traded them out, but i'm fresh out
of AAs.

 
 
 

Servo acting crazy

Post by LosiKa » Thu, 05 Apr 2001 14:28:10



Quote:
>my throttle servo is acting wierd. When the car's power and the radio
>are both on, it erractically pulses back and forth. It's doing this at
>such an amount as to make the car unsafe, as the throttle linkage moves
>far enough to go halfway to WOT.

>any ideas? batteries maybe? I would have traded them out, but i'm fresh
>out of AAs.

 Judging by the fact that your steering servo isn't messing up as well, I'd
suggest trying a second servo. If that servo mucks up as well, try a
different reciever... If THAT messes up, then try the xtals, etc etc etc...
It does sound like your servo is going south. I have a servo that does the
exact same thing... combined with a wierd "jittering backing off" thing...
It'll pull 99% throttle, then start to "pulse and let off"... unless I let
off, and then pull full throttle again, it keeps goin... It has to do with
the feedback potentiometer (JR z250 "Race Servo").

 Okay, I'm ramblin, lol. But, Give the above advice a try, and you should
be able to track down the problem.

--
~LosiKane
RC10GT and XXXT

** Hey!! I'm just learnin Nitro!!! XXXNT coming soon! **
XXX Buggy comin soon, too!!!

 
 
 

Servo acting crazy

Post by Tom » Thu, 05 Apr 2001 17:40:30


Quote:

> my throttle servo is acting wierd. When the car's power and the radio are
> both on, it erractically pulses back and forth. It's doing this at such an
> amount as to make the car unsafe, as the throttle linkage moves far enough to
> go halfway to WOT.

> any ideas? batteries maybe? I would have traded them out, but i'm fresh out

Sounds like your servo might need a jolly good clean.  Check out
http://www.csc.uvic.ca/~tyounger/hafh/rc/servo.html

___
TTTTT   OO   M   M The sixth sick shiek's sixth sheep's sick.   |~~~|

  T    O  O  M M M So if it is in it or if it is on it, it is     *  
  T     OO   M   M        as it is, be it in it or on it.        `-'

 
 
 

Servo acting crazy

Post by Divrdan0 » Fri, 06 Apr 2001 04:30:39


Quote:

>> my throttle servo is acting wierd. When the car's power and the radio are
>> both on, it erractically pulses back and forth. It's doing this at such an
>> amount as to make the car unsafe, as the throttle linkage moves far enough
>to
>> go halfway to WOT.

>> any ideas? batteries maybe? I would have traded them out, but i'm fresh out

Try switching the servos... plug the throttle servo into the steering outlet on
your reveiver... and vice-versa. If the STEERING servo starts acting up in the
throttle plug, it's your reciever.
 Same thing happened to me. Seems My receiver had a little moisture in it...
Condensation?
 (had to be condensation... I never run my trucks in mud, snow, or water...
honest, no kiddin, I don't,... really :-)
Cleaned it out and let it dry completely, no more twiching, glitching servos.
Worth a try, and won't take long. That way you will at least be taking one more
step towards isolating the problem.
 
 
 

Servo acting crazy

Post by Dave » Fri, 06 Apr 2001 13:15:23


Quote:

> my throttle servo is acting wierd. When the car's power and the radio are
> both on, it erractically pulses back and forth. It's doing this at such an
> amount as to make the car unsafe, as the throttle linkage moves far enough
> to go halfway to WOT.

> any ideas? batteries maybe? I would have traded them out, but i'm fresh
> out of AAs.

Sounds like a flakey servo.  I had the forward<>reverse servo die on my
T-maxx when I just opened the box and was checking the radio out on my
kitchen table!  Would jitter around the swing all the way to forward
position.  Went back to my LHS and we called Traxxas.  They said to change
plug on the receiver to see if its the radio or the servo. It was the
servo.  Instead of mailing in the servo and waiting for Traxxas to replace
it I bought three new Futaba 3003 servos and replaced everything.  Now I
have three cases and three sets of gears for any of my servos.  (My rustler
and sport love to eat servo gears as I found out that the cars are not
compatible with concrete blocks and sign poles.)  

Another thing to check for is moisture or water on the circuit board of the
servo. Especially around the 3 wire solder joints.  On a new servo I ALWAYS
hit the circuit board and bottom of the servo case with a liberal amount of
Tub and Shower clear silicone caulk.  Then I smear the long screws with
silicone grease before putting them back in the case.  This keeps water and
moisture from "wicking" up the screws and rusting everything.  On my
T-Maxx, I wrapped a balloon around the bottom of the throttle and direction
servos to help keep any water from even hitting the servo cases.  

With my bad fatory servo it was a bad potentiometer so it would never stop
"hunting" around.  

Hope this helps.