Problem with throttle servo HELP!!!!!

[Raypadro]

I have a 25% Extra 330L and have a problem with the throttle servo.I'm using a Spectrum DX7 radio with a mix of hitec servos The throttle servo is a futaba 3003 and the problem is only with the engine running.When I try to move the servo to apply throttle the servo glitchs and start to go move back and front in no control at all.As soon as I put the engine on iddle it holds fine.

Problem is I replace the servo with a hitec 311 and the same problem,change the extention cable for this servo and no luck.Lastly I replace the receiver(AR 7000)
and the problem persist and don't know what else can I do to solve this.

Any help is welcome.

[HuckinChikn]

Are you using metal clevises? metal pushrod? I've never experienced it, but i've been told that using metal to metal connections on a throttle linkage causes interference

[Raypadro]

Metal pushrod with plastic ends.

[Marvan Maxwell]

Hi Raypadro , this may help ,I had this happen with my JR PCM 10 on 6 meters . In a 35% aeroworks edge, the problem was I had all digital servos (8611) and a standard non digital on the throttle , I changed it to a digital and the problem went away . I called JR customer service and asked them why and they did not know ?????? hope this helps MarVan

[Raypadro]

Marvan I only have 2 servos available for testing what you said.

Futaba s9151
Spectrum Ds821

I'm using A123 2 cell for receiver(about 6.6v)without any regulator and I'm not sure if this servos can handle that current,any ideas?

[Marvan Maxwell]

Raypadro , I have been using 5 cell packs for the last 5 or 6 years , sometimes after chg they are 6.9 to 7.1 volts and no regulaors . But the new 2.4 stuff may not like that voltage ?? I no not know. are any of the Futaba or Spectrum servos digital ? just some things to think about. how far is your servo from the ing for the engine MarVan

[ericb]

The spektrum receiver should have no problem with that voltage. They are rated up to 9V I believe.

[Raypadro]

Marvan both servos are digitals.The ignition is about 4 inches from the servo.The ignition is in one side of the engine box and the servo is in the other side.It's this too close?

[Al Lewis]

Way too close.

[Rush7]

Here is the issue. You are picking up interference from the engine. I had this same issue on my Extra and I had to completly isolate the engine ignition from the servo lead.
I would sugget that you just start moving things around until you can find the problem. It all sounds like your ground could be breaking down on your ignition.
Hope this might help you......................

[mikeh]

You don't have the ignition pack around the receiver do you? That could be another cause.

[Raypadro]

Mikeh receiver is under the canopy and alone.

Rush I don't understand what you meant by your ground could be breaking down on your ignition.

Can you explain a little more and try to explain very clear my english is not that good...

Thanks guys for your help.Tomorrow morning I'm going to try a couple things of course one at a time to see if I can find what the problem is.

[Delrin]

I had the same exact problem with my GP 25% Yak. I started with the throttle servo in the engine box. It glitched like crazy. I moved it back to the radio tray and the problem disappeared. Also, use a nyrod instead of the metal "antenna" for a pushrod.

[Raypadro]

Will try that Delrin,thanks.

[Raypadro]

Problem solved,after a close inspection of anything close to this servo I found that the spark plug cap was loose on the spark plug I use pliers to close it a little bid and then put some black electrical tape on the outside of the cap to take care of any play.I put everything back on it's original position and no glitch on the throttle servo.

Thanks guys for your help Ray.