Steering issue
 

Whenever i give full throttle my servo steers sharply to the right and then goes back to neutral all in the blink of an eye.

I checked the wiring and all seems good, i measured the servo's signal which i believe was 5,66V full to the right, 5,77 neutral and 5,88 to the left which all seem good.
When steering is in neutral and i give full throttle the servo signal seems to dip to 5,75, but this may in reality be even lower since my multimeter may not be fast enough.

The servo is a Power HD S15, receiver Sanwa RX-482, and the ESC is a ORCA BP1001
This problem occured with my old receiver as well which was a Ruddog RR482

The servo signal is no voltage, it is a PWM pulse you can only measure with an oscilloscope or a special PWM meter.

I would advise to play with the EPA setting of your full throttle. If the servo get blocked at full throttle then a huge current can flow making a small voltage drop with which probably the failsafe is activated causing the servo going to center.

Agreed

They're using an ESC, not a throttle servo.

Oeps.....
Yet, it still looks like a glitch or a voltage drop. Things to try:
- place the receiver further away from the ESC
- try a glitch buster.
- try an external BEC

Thanks, i'll try moving the receiver first, and order a glitch buster just incase.
I did use the same layout on my TB Evo which had this issue aswell..

But what could be causing the interference anyway, i initially thought the ESC was pulling too much current.

An ESC is creating a high power and high frequency PWM signal creating a magnetic field. Not directly in the 2.4GHz range but more in the range of internal data signals. Any high impedance data signal can still be influenced by external electro-magnetic fields.

Another thing I have heard. Do you have a 3 wire RC4 transponder put in the battery slot of the receiver? That seems to cause issues with a Sanwa receiver.

Interesting, but no not on this one yet, my A800R has a RC4 Pro but that one isn't giving me issues.
The rest of the electronics are identical aswell.

Check your wiring for loose connections, the following issue was solved after I re-seated the servo connector back into the Rx:

https://www.youtube.com/watch?v=frkmoMhQ5AQ

The following issue was solved after fixed the HV servo harness:
https://www.youtube.com/watch?v=LneubAZ5oX0&t=35s

Solution here:
https://www.rcgroups.com/forums/show...0#post40061288

Also note that it can be anything from an incompatible servo with your ESC and myriad of other gremlins if the glitch buster doesn't solve your issue after checking for loose connections

Strange words.... Some servo's can be power hungry and so they can draw currents beyond the limits of the ESC in the BEC. But lets say a 40kg strong servo in a simple 1/10 tourer will never draw high currents unless the endpoints are not adjusted well.

Beside that, he has the issue with giving throttle, so no active servo.

It's been many years since I've seen incompatibilities but they were mostly around analog servos getting jittery from the digital signals from the ESC. It was a common problem at the track in my area and I had a list of known combinations that did not work between brands of ESC/Servo that I tracked on the URC forums, but that info was lost after URC shut down many years ago. Glitch buster did not solve the issue, new digital servo from a different brand fixed it ;)

It has nothing to do with compatible, there is no compatibility list to find. Basically such issues come from a bad or poor design and most of the time from a switching BEC

I can assure there are compatibility lists out there and it was very painful to manage when servos were still analog, the following is an example from Sanwa that compares their Rx's but it translates back to incompatible analog servos:
https://www.sanwa-denshi.com/rc/comm...e%20180704.pdf

The gist is you need to run new with new and old with old, don't mix match an old servo with a newer ESC and visa versa

...Which can cause incompatibilities despite there not being documentation around compatibility.

That is not the issue. Analog servo's are just made to work with the 50~60 Hz framerate, any faster setting like digital, SR, SSR, SXR etc. The same counts for normal digital servo's that do not support super response modes. In most ways you can set the channel to "analog". Still that is not the issue in this topic.

I would not say incompatible because high chance with others it can work without issues. A tolerance thing, design revision, wrong component choice or an alternative component choice with a production serie and lets not forget the huge amount of fake components that hit the market in Corona time. And I know because I work at an electronic production company facing this on a daily base. All issues that can not directly named as an incompatibility.

In other words, an incompatibility. Tolerances etc can lead to unintended compatibility issues.

Incompatible is directly set by design not after production detected due tolerances, a poor design or a bad component choice that all was normally expected to work.

No. Incompatible just means they don't work together.

Quick update, tried moving the receiver further away from the ESC and servo but didn't do anything noticeable.
Also added the glitch buster from Ruddog to the receiver but still no results.

Also made a video to show exactly what's happening.

The soldering and connectors all seemed fine but i'll check them again just to be sure.

If the servo is a high amp draw more than the receiver amp output, you will never get rid of the problem. get rid of the high amp draw servo.

Watching the video the servo amp draw won't be the problem because they're not turning the wheel.

Does the radio support telemetry? If it does, check the receiver voltage at the points that the servo glitches. It's odd that it always steers the same way, check your fail safe settings to see if the servo position is set. Do you have any other servos, ESCs or radios to test with to see which component the problem follows?

??? That what I was talking about. The steering servi is high amp and when you punch the throttle All the burst go to the motor and the steering servo doesn't have enough amps to not glitch If you can program your esc to low punch tthat should solve your problem?. The receiver can't supply enough power to the servo and esc at the same time. when you punch the throttle. Only other option is another servo with lower amp draw.

When the servo is idling with no load and no input it's not really drawing any current so won't be causing this problem.

The receiver doesn't power the ESC. It's the other way around, the ESC powers the receiver. Giving throttle to the ESC shouldn't put load on the BEC either, about the only thing that'll affect that is if the main battery voltage sags too much, since that battery powers the BEC.
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I swapped out electronics one for one with my other car which are all identical, i noticed that it only happenend when the motor was under load.
Different motor and different ESC seemed to make it slightly worse.

The last part i swapped was the servo which is also when the problem dissapeared.

Could the servo have been causing this somehow? I thought it just carried out commands basically. :confused:

Servo must be faulty if it's causing that.

Electronics/power wise I do not see how it happens, probably vibrations?
Probably when you tick on the servo with the back of a screwdriver it also moves.

Channel mixing.

Check to see if your throttle signal is being sent to your steering channel under mixing.

I put the electronics back onto the original chassis and i think you may be onto something, the servo stopped acting up unless you touch it in a very specific way.

[ Video ]

It baffles me, it looks to have something to do with vibrations, but it seems to do it more eagerly when i touch the servo and topdeck both instead of just the servo.
The mystery is solved though, i'll pull the servo apart to see if anything obvious is loose or broken, but i'm afraid it'll come down to a new one..

Edit : a cable was pinched inside the housing against a sharp soldering, rerouted it to the other side of the servo and all seems good for now.
Also really strange as this servo was advertised as having the cabling on the inner side, however the housing does not have the notching on the correct side to allow this, It seems to be pinched by default. :mad: