Need help! Servo twitching to the right and I've tried everything with vid!

[Crazykev]

First is my setup:

Factory Vanguard 3,150kv motor running 3S

Mamba Max Pro with the BEC only running my motor fan and Rx

Savox SV-1270TG HV running @ 8 volts wired directly to the BEC

Castle CC BEC wired directly to the Savox steering servo with Deans micro plugs and only the signal wire ran to the Rx

Spektrum DX4C

Spektrum SR410

Spektrum "glitch buster" cap hooked up to Rx in seal factory Rx box.

Antenna runs out to factory post location directly from inside sealed box by drilling hole in bottom of antenna mount.

Everytime I punch the throttle in forward or reverse the servo whips to the right. Only if I punch the throttle and always does it to the right. I have the antenna ran straight up into the antenna from in the box. I have the CC BEC wired directly to the Savox servo and have a cap on the Rx. I am at a loss with what else to try? Sorry for the crap vid. Hard to drive and record.

Picture of overall layout:



Crappy vid, but you get the idea of what I'm talking about.

http://vid19.photobucket.com/albums/b181/Crazykevwrx/002_zpsks8zclnn.mp4


I would appreciate any help for what may be going on here. Thanks guys!

 

[ninja turtle]

I'd try running a ground wire from the servo/bec to the Rx.

 

[Crazykev]

I'm willing to try anything. I know that you aren't supposed to run two BECs tied together, but just running the ground shouldn't close the circuit, so I guess it won't hurt anything?

I was also considering using only the CC BEC to run everything. Only reason it is setup how it is now is because I was going to install the 2 speed kit and run the factory old steering servo to shift. That servo won't handle 8v and now I no longer want the 2 speed because I don't want the added weight and rotating mass. I don't do any sort of crawling at all. The fan only draws .23amps and will be just fine running at 8v.

I personally think that the voltage is dropping and is why I threw the cap in.

 

[rcbasser]

My guess is the servo is not "communicating" with your receiver properly. Try using Holmes Hobbies receiver bypass harness. If it is the above or a "grounding" issue ( like Ninja Turtle suggested ), this should fix either.

 

[Crazykev]

Well I fixed it, but can't tell you why it didn't work how it was set up before. I just totally ditched the MMP's BEC and have everything running on the Castle CC BEC. I figured I would give it a try and it has worked. I went ahead and left the glitch buster cap hooked up too. I already have it and it sure isn't going to hurt having it.

My only guess is that I was feeding the Rx 7v and so the signal output to the servo was coming from the Rx and the servo was receiving 8.2v. I honestly have no idea and that is my best guess?

Whatever was causing it, is gone now. I'm sure the CC BEC can handle the .23amp 40mm motor fan I have and the Savox servo. I haven't ever found the amp loads for the Savox SV-1270TG HV, but it has to be really high being that it's specs are 487oz and .11 transit at 7.4v and I'm pushing 8.2v to it and at the very least those specs must be 500oz and .10 transit! I would really like to know exactly what the amp draws are though.

 

[gbean]

1. Don't over volt the servo.
2. Always have the servo ground and the rx ground tied together with the BEC ground.

You were likely experiencing ground loop noise and exacerbating the problem with too much voltage.

 

[DenisLM]

I have the same servo and it works great with the CC BEC (at 7.4V) and the Spektrum radio. The grounds are tied together with the ESC but the 7.4V is only feeding the steering servo. The radio and the 2 speed servo get the 6V from the ESC.

 

[Crazykev]

I'm sure that it was that I didn't have the ground tied in. Only reason I had the CC BEC running only the steering servo was because I planned on having a 2 speed and I no longer even want to do that. It was easier to run everything like I would normally do by bypassing the ESC's BEC. It's working perfect now.

Thanks for the input guys! At least I know what I have to do if I change my mind later.