Throttling up causing servo to jitter

]Hi all,

I am encountering servo jitter when throttling up. It’s the back left servo only.

My TX is a Devo 10 and I’m flying the V977 heli and I recently loaded Deviation into the TX.

For the last couple of weeks, flying the heli has been normal, no servo jitter at all. Today, I noticed the jitter and thought my servo was on its way out.

So I decided to change to a new servo. But same problem. Through elimination, I tried changing the receiver board, then ESC but still same problem. Now the new servo is not working and stuck in the maximum “up” position.

I also tested the TX with my other heli and the same jitter problem. This made me think my TX is now the problem, either software or hardware. So I tried installing the latest nightly but same result. Then tried the base Devo v5.0.0 but still servo jitter. I’m figuring now it is hardware issue. BTW, I bought my Devo 10 second-hand and converted it from mode 1 to mode 2 and installed the 4-in1 and Deviation.

Questions:
1) is my throttle stick malfunctioning? If it is, any suggestions to self-repair? Or worse case scenario, find new part/parts?
2) can low battery voltage cause this problem? ( I noticed the battery strength was around 9.0v when the servo problem surfaced. Then the voltage dropped to 8.7v while I was testing the TX with the other heli.
Jitter occurs even with full battery strength and seemingly worse.

TIA

PS. I did more testing on the other heli and it seems that the jitter problem is now in the range from mid-stick zero when pushing the stick downwards. Intermittently, it happens in the same range on the way up and to both L and R servos also. When in idle-up, the jitter is not there or greatly diminished.

The jitter is getting worse and occurs even in idle up in both travel directions of the stick. Now, at zero travel, the servo intermittently jitters.

Does channel monitor on the devo show the jitter?
Have you tried calibrating the tx?

Hi Gerry,

Thanks for taking the time to reply.

I checked the channel monitor according to your suggestion and the jitter doesn’t show up on the channel monitor for throttle but I did notice the “0” in the rudder channel 4 flickering slightly when moving to the top and showing negative sign (-) briefly. Could this be the problem?

And yes, I tried calibrating the TX from the beginning as I that was my first thought too.

do you have stock WL Toys transmitter or another devo to compare or test with?

I don’t have a stock WLtoys TX but I managed to get hold of a Devo 7E to test/compare it with.

The results are a little startling. Because it seems like the jitter problem also occurs with the Devo 7E. I’m surprised why the previously unaffected heli (no servo problems) is also now showing signs of the servo jitter. I’m beginning to wonder if the problem can be transmitted (pun not intended) from one TX to another via the heli receiver board?

Rather perplexing.

can you share your model ini

Ok will do in a while. Am out and away from comp at the moment.

other than model6.ini has protocol option 1Mbps = yes, I think it should be = no, I can't see anything that would cause your issues.
I would be double checking heli mechanics and electrics. Rx board loose or not damped? Swash moves smoothly up and down main shaft? Main shaft bent? Loose or binding linkages?

Gerry wrote: other than model6.ini has protocol option 1Mbps = yes, I think it should be = no, I can't see anything that would cause your issues.
I would be double checking heli mechanics and electrics. Rx board loose or not damped? Swash moves smoothly up and down main shaft? Main shaft bent? Loose or binding linkages?

Roger that on the software side for model.ini.

Will go through the heli mechanics and electrics as suggested. But you have an interesting point on loose linkages. I was always under the impression that loose is good for freedom of movement. And my problem heli does have rather loose linkages on the swash ball joints.

Anyways, will go through step by step and report back. Thanks for checking out the model files.

Best regards
H