Hello all, it has been a minute since I last was here. I am on a different kind of project right now and have a servo question. The project is setting up a commercial zero-turn mower for RC.
I have all the hard parts pretty much nailed down, but the one I thought would be relatively easy is turning out not so much. I am setting up an FPV system with a Walksanail Avatar HD camera.
I have Sky Zone Cobra V4 goggles, and I downloaded and 3d printed the parts needed to put together a simple pan and tilt setup from Painless 360 on YouTube.
I’m using the Walksnail VRX to plug the HDMI from the goggles to the VRX and am plugging the goggles head tracking cable into my FrSky X20s ethos radio.
That all works pretty much flawlessly; the problem I’m having is the pan and tilt 9-gram servos keep burning up, and I can’t find any reason why.
The one thing I’m wondering about is my servo wire length.
Because of the physical locations of my head tracking servos and my receiver in my electronics control box, the wires need to be about six feet long. Would servo wire length possibly cause servos to brick?
One of the first servos literally melted down, and the smoke visibly left the building. I have continuity tested all six of the individual wires, and they are perfect in every way. If I plug a servo with a stock-length lead into the pan and tilt channels, it works fine. I’m kind of out of ideas except for the wire-length thing.
- Can they provide enough torque for your setup? Normally a servo should operate at ~25% to 30% of its rated torque. 9g servos are very small.
- Is the servo blocked before it can reach its final angle? This would cause it to stall and burn quickly
- Are you somehow feeding it at a higher voltage than it’s rated for?
- How long is the cable
Don’t know your system’s specs. To prevent burning up 9-gram servos, make sure you’re using them within their specified limits, providing proper voltage, and ensuring there are no mechanical issues or excessive loads.
Hey, that’s a really interesting setup — sounds like a fun project! Six feet is quite a stretch for servo leads, and yeah, wire length can definitely become an issue, especially with smaller 9g servos. Long runs increase resistance and voltage drop, which can cause overheating if the servo draws more current to compensate. Signal degradation can also happen on longer PWM lines if they’re unshielded or routed near power lines.
If you haven’t already, you might want to isolate the problem by testing each servo individually before mounting them back into the rig. A Digital Multi Servo Tester is super handy for that — it lets you simulate PWM signals, sweep the servo, and check for current spikes or abnormal jitter without connecting to your radio system. That way, you can confirm whether the servos themselves are fine or if the issue lies in the wiring.
You could also try running heavier gauge servo extension wire or adding a small capacitor near the servo power lines to smooth out voltage dips. It’s often the simplest way to stop those “magic smoke” moments before they happen again.