Small glitch with my Hitec 7954 servo

[2-shot]

I'm finishing up my Wraith build and got all of my electronics wired up and powered up today. Everything is good, except for my Hitec 7954 servo glitches every 2 to 3 minutes. It glitches the same if the wheels are straight, or if I have it at full lock in both directions. When it glitches, the servo quickly moves in one direction maybe 1/8" - like the servo twitches. It's like someone quickly and lightly bumped the steering wheel on the transmitter. If the truck is sitting still, the servo will glitch. It will also glitch while moving. I've only ran it indoors today for a few minutes to test the electronics.
The throttle is working great - no glitching!

Here's what I have installed for electronics:

Hitec 7954 - new
CC 10amp BEC (set at 7.2 volts) - used
Rx bypass plug - used
Tekin RSX - new
Tekin ROC 412 3100kv - new
Futaba 4PLS and receiver - new

I do have my receiver mounting in a RC4WD aluminum fuel cell receiver box in the rear of my Wraith. I have the receiver antenna coiled up inside the fuel cell box.

I've never had a servo glitch issue before. I'm kinda puzzled on what could be causing it. My first thought was the receiver being enclosed in the aluminum fuel cell receiver box, with the antenna coiled up inside the box. But, I'm not having any throttle glitching...
Maybe my RX bypass plug or BEC is bad, or going bad?

I wanted to get some opinions or ideas on where I should start with troubleshooting the glitch. Maybe someone has some experience with the same or similar issue.

Thanks in advance for your help and input!


Sent from my modded TI-83 plus

 

[SINister]

If you haven't already try plugging the servo directly into the RX without the BEC and bypass. If it still does it plug the servo into the throttle channel since it seems to be working fine. That should help you narrow down the problem.

 

[2-shot]

If you haven't already try plugging the servo directly into the RX without the BEC and bypass. If it still does it plug the servo into the throttle channel since it seems to be working fine. That should help you narrow down the problem.

Thanks!! You're right, that would be a good starting place. Start eliminating possible culprits of the problem.
One thing I just thought about. My internal BEC my Tekin RSX is set at 6.0v. Even though I'm running a BEC and a rx bypass plug, I wonder if I should bump up the internal BEC voltage to 7.2v???


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[JokersWild]

Thanks!! You're right, that would be a good starting place. Start eliminating possible culprits of the problem.
One thing I just thought about. My internal BEC my Tekin RSX is set at 6.0v. Even though I'm running a BEC and a rx bypass plug, I wonder if I should bump up the internal BEC voltage to 7.2v???


Sent from my modded TI-83 plus

Nah, should be fine at 6 volt. Nothing there to draw power....... What bypass adapter are you using.......? Maybe grounding issue? You check actual voltage from bec? If over 7.2 it may freak out. May have pot issues or bearing issues on servo

 

[2-shot]

Nah, should be fine at 6 volt. Nothing there to draw power....... What bypass adapter are you using.......? Maybe grounding issue? You check actual voltage from bec? If over 7.2 it may freak out. May have pot issues or bearing issues on servo

I think the RX bypass adapter is from Holmes Hobbies, but it is used. I've had it in a couple rigs. I have a couple more of them, maybe I'll swap it out with another one. I have not checked the actual voltage coming from the BEC.
The servo is brand new. I'm not saying it doesn't have issues. It could be a bad servo out of the box.

You guys have given me some ideas on where to start. Like I said, if built 4 crawler rigs and numerous go fast race rigs, and this is the first glitching issue I've had with any of them!

Thanks for your help!!! Much appreciated!!


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[JokersWild]

Like stated, drop the adapter....... Swap servo to another rig....... Etc etc. Process of elemination

 

[2-shot]

So I have an update to my servo glitch / twitch issue. I was looking everything over good, with the esc and servo powered up. The servo does it twitch thing when the lights on the Tekin RSX blink from LED 3 & 5 to LED 1 every few seconds. It's normal for the LED's to do this on the RSX. LED 3 & 5 blink while not moving to show it's in blinky mode. The RSX will blink the #1 LED every few seconds to show that the ESC is at ambient temp. This is when my servo twitches!!! It twitches when the esc LED's blink the #1 LED!!!

Could that be a ground issue???

 

[2-shot]

Update!!!

I figured out my issue!! It's the rx bypass plugs. For whatever reason, my setup doesn't like them. I tried 3 different rx bypass plugs, and all 3 caused my servo to twitch. I removed the rx bypass plug and ran my BEC through my receiver.
Good to go, now!! No more servo twitch!!

Thanks again for everyone's help and input!!


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