I have a 7954 HV on a 35%. Right elevator servo is shaking, all other control surfaces are nice and quiet. All servo's have about 20 flights on them. I run two 2500 A123's. I have checked connections and inspected the wire's. Unhooked the elevator and the servo seems quiet, put any stress on it and it wants to shake. I don't trust it, any help would be helpful. Thanks Eric

Apparently it's perfectly normal as per this thread -> https://www.flyinggiants.com/forums/...highlight=7954

Hi

I have Hitec7954's in my 30% plane and I like them. I did have a problem with them jittering and i sent them back to Hiitec and they fixed them free of charge, there customer service is very good

Scott

Originally Posted by wally3185

I have a 7954 HV on a 35%. Right elevator servo is shaking, all other control surfaces are nice and quiet. All servo's have about 20 flights on them. I run two 2500 A123's. I have checked connections and inspected the wire's. Unhooked the elevator and the servo seems quiet, put any stress on it and it wants to shake. I don't trust it, any help would be helpful. Thanks Eric

i have them on an EF Extra 60cc.......my left elevator shakes........but it is pretty normal.....flies fine and no bad tendencies in air...

apparently it is due to long extension wires although i use hitec heavy duty ones....try plugging yours directly and see if it happens.

i'd say its normal and go out there and fly!

Originally Posted by wally3185

I have a 7954 HV on a 35%. Right elevator servo is shaking, all other control surfaces are nice and quiet. All servo's have about 20 flights on them. I run two 2500 A123's. I have checked connections and inspected the wire's. Unhooked the elevator and the servo seems quiet, put any stress on it and it wants to shake. I don't trust it, any help would be helpful. Thanks Eric

You neglected to mention which receiver you were using. There is a known compatibility issue between the Spektrum Powersafe receivers and long extensions wires, but that's glitching to the point where the surface would move about an inch or more, and it's unpredictable and random.

Jittering, where the servo wiggles back and forth just a tiny bit at center, isn't something huge to fret about. The 7954 is a high resolution servo and on HV setups that can make the jittering more prevalent. The servo is essentially trying to center very rapidly and with no load on it there can be a minute jitter at center. When you get airborne and airflow begins to flow over the control surfaces, there will be a load put on the control surfaces and the jittering will go away entirely.

If you feel uncertain or uncomfortable about the servo, send it into us and we will take a look at it:

http://hitecrcd.com/support/warranty-service

I am running a Spectrum Power Safe. My concern is that this servo wasn't doing this before and the left elevator is quite, with the same length of servo lead. Would it help if reprogramed the servo? Thanks Eric

Originally Posted by wally3185

I am running a Spectrum Power Safe. My concern is that this servo wasn't doing this before and the left elevator is quite, with the same length of servo lead. Would it help if reprogramed the servo? Thanks Eric

You can try to reprogram if you want, set everything back to factory defaults (use the RESET function).

Like I mentioned before we seem to have some sort of compatibility issue with the powersafe receivers and our high res servos. Are you able to upload a video so I can see first hand?

Xpress,tried to upload video, wouldn't let me? Do you have an email I could send it to. I'm at ericruggles@att.net

Upload it to YouTube and post the link here.

MOV01124 (0 min 24 sec)

If you apply a slight load to the servo, does the issue go away?

When I touch the elevator it will take 95% of the jitter away, down to what I would consider normal. After 5-10 seconds it always comes back to what you see in the video.

HOLY MOLY!!!

Besides the obvious, another consequence of having jittery servos is battery consumption. They are eating milli-amps with every oscillation.

Originally Posted by wally3185

When I touch the elevator it will take 95% of the jitter away, down to what I would consider normal. After 5-10 seconds it always comes back to what you see in the video.

The issue is a Minimal Load Jitter. Typically only happens when on the ground with minimal loads on the servo. Basically the servos circuit is trying to compensate for the tiny amount of play in the gear teeth and it's mostly only notable on HV. When you get to the air, the airflow will put a load on the control surface and cease the jittering entirely.

If you want, you can send the servo into us and we can look at it and see if there is maybe an issue inside of it, but based upon preliminary assessments, there doesn't seem to be much of an issue.