X06 servos go crazy with GR6

[Landru]

I've run into a very odd problem with a brand new GR6 receiver and four brand new X06 servos. As shown in the video below, the servos move almost continuously without any command input.

The problem occurs with all four servos whenever telemetry is enabled for the receiver. Reducing the telemetry power to 25mW has no effect. However, disabling telemetry entirely removes the problem. At least, in my limited testing it seems to. Whether it's a fully reliable solution is yet to be proved. Plus, I'm not keen on giving up telemetry.

The video shows the equipment located close together so I could capture it all in the video frame. However, the problem still occurs with the transmitter and receiver at 1m distance from the servo.

To make matters stranger, I cannot reproduce the problem with other servos I tried: KST X08, FrSky 5601 HV, an old GWS analog. Plus, the four suspect X06 work flawlessly when connected to a GR8 (ACCESS) or G-RX8 (ACCST v2) with full power telemetry. I've tried different firmware versions on the GR6 and different power sources. No dice. Changing the PWM rate for the GR6 changes the frequency of the glitching but does not remove it. Once or twice, the servo did quieten down. However, the problem re-emerged after the receiver was power cycled.

Anyone come across something like this before?

I've experienced mild jitter in servos caused by telemetry before, but nothing this extreme.

Andrew

 

[HENNY]

What happens if you move the TX 2 meters or more away from the servo and receiver. You could be swamping the receiver and gear with TX RF. Some servo have not or little tolerance to RF.

 

[Konrad]

I suspect there is a weakness in the layout of the GR6. What is that you need with the GR6 that another 6 channel RX can’t offer?

As a “fix” try tying some knots down the servo leads. Braiding the servo leads or using a ferrite bead. Straight ribbon leads act like antenna picking up the RX telemetry transmission swamping the servo command signal. All servo leads should be of a twisted design. Flat ribbon is only used to aid robotic assembly.

 

[Landru]

Thanks guys.

Moving the transmitter to the other side of the room (~3m) had no effect.

I had purchased this GR6 for a 1m DLG. My preference would have been a G-RX6 but they weren't available at the time. As it turned out, the project got set on the back burner and now the G-RX6 is back thanks to Aloft.

The GR6 and X06 servos seem to be a popular choice for DLG. I can't imagine everyone resorts to disabling telemetry, at least not for sport flying. And I haven't read any reports of adding ferrites or other special treatment. The GR6 design may have design flaws but I'm starting to suspect that my particular unit may be defective in some way. In any case, I don't think I can use it as intended.

 

[Konrad]

With the use of the X06 I had assumed that the ferrrite rings wouldn't be a practical solution, unless the X06 were used out of space concerns rather than weight concerns. All the fixes I suggest are what I often use to suppress noise on my long servo leads. I find neat wire looms are often much noiser than rat's nests. Just trying to find something to quite the noise then backtack to a practical solution.

DLG, why would one want a the FrSky Glider RX in one of these? I hope it isn't for the Vario. In my flying I find that hunting for low level thermals that any vario is next to worthles as the responce is late and they don't tell me where the thermal is. I find DLG is all about reading the ship as she is signalling where the thermals are. Having a vario tell me that I've stumbeled into one doesn't help me. In fact I find varios detrimental as I get distracted and fly the tone and often chase stick thermals!

I'm not saying there is a design flaw, as you say other appear to get these to work. I assume they are useing telemetry reporting (batery and signal strength).

 

[Landru]

In a DLG, the altitude data is useful to know launch height.

In fact, I prefer to have a vario in all my gliders for data logging purposes. Like you, I find the vario itself of no help in flying. However, I do often use altitude callouts every 10s. I find them useful for keeping track of range when the model is high. But as you said, there's far more useful info on thermals to be gleaned just by watching the glider and feeling the wind.

 

[Wayne]

A lot of folks use the vario with a LUA script that helps grade their performance with the DLG. Pretty neat really.

I'll go setup a test with the same gear here and report back.

 

[Landru]

Super. Many thanks, Wayne.

 

[Konrad]

I can see I'm real old school. Data loging and maintaining data bases reminds me of work (flight test)!

 

[Landru]

I hear you. Sometimes the computer-related stuff in the hobby does feel like work.

 

[Wayne]

OK - same gear, 1 servo, no issues.

 

[Wayne]

Can you get that ESC out of the loop and just run a 2S lipo or MiHM battery instead?

 

[Landru]

Thanks, Wayne. I've already tried a NiMH pack (4 x AA). It didn't solve the problem. I'll try 2S Lipo and report back.

Really appreciate the awesome hands-on help!

 

[Konrad]

I hear you. Sometimes the computer-related stuff in the hobby does feel like work.

Computers? Heck I'm talking file cabinets!

 

[Wayne]

Pretty sure this is a popular combo of this receiver with those servos, for sure would have heard from others if this issue was repeating.

More than one servos does this for you?

 

[Landru]

Ok, now we're getting somewhere.

• With 2S Lipo at ~7.6V, the X06 test servo behaves properly even with full telemetry power.
• With a CC 10A BEC outputting 5.1-5.2V, the servo jitters a little.
• All four of my X06 experienced the problem when tested with NiMH at ~4.8V or the ESC BEC at ~4.9V.

So it's starting to look like a voltage-dependent issue.

However, the mystery remains as I'm pretty sure the GR6 / X06 combo is often used on 1S.

 

[Wayne]

I have my sample here powered by 4 Nimh. Perhaps there is something wrong with this receiver you have where the receiver is not getting clean voltage, but the servos are. Take a look at the header pins, we occasionally see a junky solder joint that was able to pass the automated QC tests. Sometimes reflowing those joints will get things going well again.

 

[Landru]

Good call. I previously looked at the pins and saw that not all had solder that had flowed from one side of the board to the other. Perhaps that's the culprit.

I'll take another look and see if my skills are up to resoldering the pins. Should be, I think.

P.S. On reflection, there's some other circumstantial evidence for poor soldering. A couple of times, a servo was totally non-responsive. And just now, I had to unplug and replug the 2S Lipo to get the receiver to power up.

 

[Konrad]

I have my sample here powered by 4 Nimh. Perhaps there is something wrong with this receiver you have where the receiver is not getting clean voltage, but the servos are. Take a look at the header pins, we occasionally see a junky solder joint that was able to pass the automated QC tests. Sometimes reflowing those joints will get things going well again.

Good job, this kind of remote troubleshoot is very difficult, well done, both of you!

 

[Landru]

Ditto to Wayne!