New Radiomaster RX killing my servos?

[cd0g17]

Hey Guys,

Facing a really weird problem right now.
Recently purchased a new radio set. New Radiomaster TX15Max and 2x ER4 and 1xEr6G receivers.

But for some reason, my analogue 9g servo's are just breaking on these new RX's. I know it sounds super odd. But I have 8 dead servo's now on what were once perfectly working planes. Some old, some new, all purchased different times. To prove I am not crazy, I made a video and took a gamble on a working servo and sure enough it broke once I connected the ER6G. In the video I show that the servo is working perfectly on a Flysky setup, then I change to the new Radiomaster setup and within about 3-4 seconds, the servo gives in. It now won't work even if I go back to the Flysky setup. 1 servo I can accept, but 8?

Things I have checked:
* Edgtx on TX15 is the latest 2.12 available from Radiomaster's website.
* ELRS is the latest - 3.6.2 on both TX15max and Er6G. (It was originally on 3.3.1)
* I have not yet updated the ER4 yet but thats still on 3.3.1 and it also breaks servo's.
* I have tried with 3 different escs. 30A, 40A, 30A, all with built in Becs.
* The BEC puts out exactly 5.01v on my esc's according to my multimeter.
* The pin outs on both the Raidomaster and Flysky RX's are also 5.01v.
* The servo's are set to 50hz on the Radiomaster RX in the WebUI

If anyone has experienced this problem, please do let me know how you resolved it.
Yes they are cheap servo's. But I have never ever ever had one fail on my FlykSky setup.

My short video of a servo just giving up on life after the new Radiomaster rx is connected:

 

[LitterBug]

Make sure you are using 50hz with analog servos. They can not handle faster pulse rates.

Go to SYS -> ExpressLRS -> Packet Rate

If it is higher than 50 Hz, that is what is doing it.

 

[cd0g17]

Thanks for this @LitterBug ,

I have thought about that and I have checked my RX's webUI menu and it shows that it is set to 50hz on the receiver. See below screenshot

I am a bit confused now, is "Packet Rate" in the ELRS menu the setting that sends the signal strength to the servos or is it this "Output menu" on the receiver itself that sends the signal to servos?
I ask this because my "Packet Rate" on my Radiomaster TX15 transmitter is set to 250 2.4Ghz as my research said that is a good balance between latency and distance. My thinking is that this is just the signal strength setting between TX and RX and not signal from RX to servo.

 

[LitterBug]

You are correct it is the setting on the RX web interface that matters, not the packet rate.

 

[LitterBug]

Check the throws. Make sure your servos are not in a bind at max stick position. Not sure what radio you are coming from, but the throws on EdgeTX tend to be bigger than some other radios.

 

[cd0g17]

I haven't messed with any throws yet, I think its still on the default 100%. And I am coming from a FlySky fS-i6X setup. Generally with my 9g servos, if they get stuck or bind they make a noise and I can hear it immediately and thats when I change pushrod positions on the horns etc etc but I am not hearing any of that. Its like it works perfectly fine for about 3 or 4 seconds on the radiomaster and then stops and thats it.

 

[Piotrsko]

Sounds like you are frying the signal input on the servo. Duh. What happens if you use a couple of 12" long extensions in series or mostly dead lipos ?

 

[LitterBug]

What voltage input are you using? Straight off a battery or a 5V BEC?

 

[Bricks]

Do you have a volt meter check voltage coming out of the + - pins of the receiver a long shot as that should be controlled by the ESC.

 

[cd0g17]

Thanks for the replies guys. Using 3 different esc's with the built in 5v Bec to power the radiomaster rx. My voltage readings are 5.00v on the bec and 4.99/5.00 on the radiomaster pin outs.
All 3 of my new radiomaster RX's are set to 50hz on the webUI.

I think all I can blame right now is that my 'well-used' (ie, couple flights) servo's can't handle being rapidly moved - they just burn out.

I have since replaced the 8 broken servo's on my 3 different aged planes. But I am not rapidly moving them. Just a few movements to ensure they operate smoothly and move enough of the control surface and then leave it and go fly.

 

[Piotrsko]

Go find an old servo or three? Mine all run 6-7v all day long. (Dry cells way back in the day) might even go higher than that, vaguely recall my gen 1 futaba servos running on a 9 volt cell for a while