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Throttle servo acting up, need help

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M

mulgore

RC Newbie
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New to the site, hello all!

I can turn on the truck and all the servos reset normally. But when I turn on the radio, the throttle servo looks like it reverses and almost bends the linkage backwards. I can then turn everything off again, turn on just the truck, and the throttle servo resets to normal.

My little one left the truck on overnight but let it fully charge again and still happens, if that info helps. Bad servo??


I just had it out a day ago and everything worked fine, cept it wouldnt keep running-which new glows took care of that. Now it idles fine but no thorttle :(

Any advice would be great.

Thanks.
 
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Have you looked at the servo reversing switch on the transmitter? Sounds to me like a simple fix, flip the switch on the radio. If this doesn't fix it, let us know... someone on this site will know how to fix it.


Oh, and....Welcome to the forum.
 
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Thanks for responding!

Yea, I've tried that and it didnt change how it acted when the radio came on. O, let me add that the trigger does nothing when i apply gas or brake. When i was reversing the switches, I still get no action from the trigger.

Thats the odd thing, when i turn the truck on w/o radio, the servo resets to center (i guess thats what you would call it). If i have the radio on first and turn on the truck, it acts up.

I'm not getting the "twitch" like a dieing battery on the throttle servos either...
 
Reverse the two servo plugs in the receiver. If it's the same servo acting up you need to replace it. If it's the other one, the problem would be in the radio or receiver.
 
Before you buy a new servo, try connecting the servo the the receiver without the optidrive. Personally, I think the optidrive is a joke. Simply unplug the throtle servo from the optidrive and plug it in where the optidrive plugs into the receiver. If this fixes the problem, you know what your faulty item is. Does your steering respond properly?

I purchased a failsafe and removed the optidrive from mine, but If you do this, you would want to install the forward only kit or the center diff also. The optidrive is supposed to save your reverse gears in the transmission, but didn't work for mine.

Hope that this helps you out. Don't get frustrated. One thing to remember... If you are not breaking something, you are not driving hard enough.
 
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No Problem... That is why these forums are such a great tool... what one person forgets, someone else remembers... I can't remember everything, and may have to rely on you at some point.

Thanks
 
Just something to consider. If I take the crystal from my Revo transmitter and plug it in the Stampede transmitter ( One was out of batteries, too lazy to swap em ) it acts the same way. The throttle just steadily backs and locks there exactly like what you described.

I don't have a solution in your case but maybe one of our pro's can use this to help diagnose?
 
Buy new batteries... just kiddin'

I would think that swapping the crystals would work. Don't know what to tell you on that one.
 
Ok..

I attempted to bypass the opti-crap but didnt seem to find the right combination that would work to remove it from the series.

I fully charged the truck and bought new batteries for the radio and did get a different response. Now, I can turn on both and 50/50 on it acting up. I'm starting to think I have a bad wire somewhere.

I can shake the truck and the wiring it you can hear the servo centering, then going back to the backwards thing. i handled all the wires seperately but none seemed to be the exact cause.

Still, the throttle works half the time now but still looks as if it isnt going full throttle when it does work. I did swap out both crystals, radio and truck, and that didnt change how it acted.

I guess it might be time to take it to the shop and see whats up with it...

Edit: Is it just possible the servo is going bad? Do they usually just die or can they just freak out like this?
 
The servo plugs into the optidrive... the optidrive plugs into the receiver.
Just plug the servo into the receiver without the optidrive connected at all.

My servo just had a dead spot when it started going out, and yours seems to be working ok. I would think that is a Tx/Rx problem. Did you shorten the antenna wire? Are you sure that there is no interference?
 
DONT TAKE IT TO THE SHOP!! that wont help you fix it the next time it happens.. try the process of ilimanation.. switch your stearing servo and throttle servo, just pull the servo horn off so the servos are free spinning.. and see what happens.. if the problem is designated to that one servo, the chances are its bad. if the problim switches to the stearing servo then chances are it a wierd problim w/ the receiver. durring this process, elimanate the opti drive.. some body correct me if I'm wrong, its bin so long since i had the opti drive in my revo.. does it act as a fail safe? if so, then when the reciever is on and the transmiter is off(as you stated), the fail safe will kick in, thus setting the throttle servo to "brake" mode.. leaving that on will blow out a servo.. to check to see if your throttle is opening all the way.. just center your throttle dial on the radio, hook back up the throttle linkage(servo horn) and take off the air cleaner. look into the carb barrel and see if its opening all the way. that will also help you with tuning and other trouble shooting in the future... COME BACK AND LET US KNOW WHAT HAPPENS SO WE CAN FINISH HELPING YOU... IF YOU TAKE YOUR RIG TO THE SHOP IT WILL MAKE US FEEL UNWORTHY OF OUR COUSE IN HELPING EVERYBODY.. dont:surrender

to answer your edit: i have only had 1 servo that i can rember just die.. most of my servo's wind up going crazy and taking a FIT before they stop spinning.. heavy glitching and sputtering, and not going full throw.
 
LOL, ok.. ill give it more effort tonight..... lol...

I just had a major :constipat (brainfart :P) by the time i got home, I'll give it more time tonight after work..
 
Ghosts in the machine.......

Get home lastnight and broke it out... tried it one last time before I pulled it apart and it worked fine. I'm so confused...but happy its working.

Temporary stay of execution on the servo perhaps?

Either way, thanks for all the help and the motivational speak to not take it to the shop :0:bow:
 
Yea, didnt figure the honeymoon would last long. Went to take it out over the weekend and it started doing the same thing again so I did what was suggested.

I bypassed the opti-crap completely- Still freaks out

Switched the reverse and steering servo leads with the throttle- Throttle worked both servos just fine. I was able to use the trigger to turn the wheels and reverse servo.

When ever radio was applied, it would freak out the steering servo no matter which lead it was connected to.

So i'm assuming the servo is going south.
 
Servo Problems

Hey Fellas..I hav bought a RC Buggy..
It Ran good for one round..when i fueled it for 2nd tym..the engine din start..
Den i found a prob that was with the throttle servo..
actually when i turn on the transmitter and receiver rather den being at neutral position the throttle servo shifts to full throttle position all by itself..
Bt My Brake mechanism is working...Still the initial position of the servo is the same at full throttle..!!!
Plz Help me out..I hav n upcumin event..!!
 

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