Pixhack v3 dont start up with the PWR wire

Hi, im Cristian, new with the pixhawk technology.

i’m having a problem with the Pixhack V3 controller, in a quadcopter bought to a particular manufacturer.

The problem is, when i connect the batteries x2 6 Cells 22.2 V 488.4 Wh 22000 mAh. to the dron.
The peripherals starts, the gimball stabilizes, the rotors spins, but the main controller won’t start even the main LED don’t start .

When i disconnect the POWER wire from the Pixhack, the controller start, the status LED starts, and the ARM button powers up.

Any idea or suggestion? THANKS!!!

What POWER wire? From the powermodule to the pixhack? Sounds like you’re shorting something.

From this video, I learned that the Pixhack v3 can be powered EITHER through the ESC’s or via the POWER wire. Watch the tests they do between 3:42 and 4:50ish: https://www.youtube.com/watch?v=ax5obKcmSmA&t=3m42s

I recommend that you try the tests they performed and see if yours behaves similarly, or not.

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yes, the power wire comes from the power module.

and seems to be right

thanks! i watch the video and i can deduct the Pixhack has powered via the ESC’s connector, but, why this shutdown when i connect the POWER wire? thats make me crazy.

i tested with a voltmeter the power wire and this delivery 5v.

What happen if you just plug in power without anything else?
Just USB?
Why the Rotor spinns without fmu Start?

when i plug the usb, the pixhack starts and i can connect to the mission planner.

the rotors dont spinns, just make a little pulse

You seem to only be answering some of the questions that @Cipta and I are asking. Please answer them all, to help us understand what might be wrong.

You didn’t answer this question yet, right? Please answer it.

At 4:11 on the video I linked, they connect the battery and see the system initialize correctly. Does yours behave like this?

At 4:20, they measure the output on the rail to be 5.15V. Does yours behave like this?

At 4:28, they disconnect the power and see that the backup power works. Does yours behave like this?

At 4:45, they show the current draw when powering the system ONLY via the power cable. Does yours behave like this?

At 5:15, they verify that the power cable does not supply servo-power. Does yours behave this way as well?

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when i plug the usb, the pixhack starts and i can connect to the mission planner.
the rotors dont spinns, just make a little pulse.

OK, when i connect the battery the pixhack dont start, but the peripherals starts.
when i disconnect the power wire, but the batteries keep plugged, the pixhack starts and starts the leds lights.

i measure the output of the power wire and is 5.0v

when i disconnect the power, the backup power works.

i dont test powering the system only via the power wire.

i will update when done the test.


So you are connecting 2 batteries in series to the power module or in parallel to the power module? Because as far as I remember, the Power Modules can not handle more than 6S configuration. I could be wrong , but that was my experience so far

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yes, have the 2 batteries in series, but previously the pixhack works fine with that configuration

today, i tested unplug all the servos and ESC’s connector, only powering via the POWER Wire, and nothing happens. the voltage of the power wire is 5.0v.

im testing the 5.0v on VIN + and GRND -. Testing on VOL_S & GRND give me 3.0v

Most Powermodul should deliver five point three Volt. What kind of PM you use? May you can test another one or power suply. If that doesn’t work I would say the pixhack regulator is not healty anymore.

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Good test. I think this demonstrates that there is something wrong with the power circuitry inside your pixhack. If you have the ability to exchange or replace it, that’s the best option.

But, if you don’t have the capability to exchange or replace it, you might try the suggestion by @Cipta to provide 5.3V via a power supply. If that works, the problem is actually with your power module, as @Cipta suggests, which is a less-expensive replacement.

The video linked above (at 4:28) called powering the system via the Servo rail a “backup power source.” Does anyone know if it’s dangerous to power your system exclusively this way? (and just leave the “power” input disconnected)

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Thanks! i will replace the PM buying another new, or maybe powering the Pixhack with a 5.3v and 0.24 A power supply.

with this, the pixhack should starts normally.

when i start the pixhack only powering via the servo’s, it’s impossible arm the drone and connect to the mission planner.

Just a quick note on the above, if you have the breakout USB and led module plugged in- the main LED will not light at all. I can’t tell from your image if it is plugged in but it’s a quirk and I wish it wasn’t a ‘feature’, but it is. This may not be your problem but will hinder your trouble shooting if you aren’t ready for it. 2 6s batteries in series is 12s. The cuav pm is good for 6s maximum so that may be the culprit although I know this has been discussed above. More pictures would help us.

Thanks everyone helped to find the solution for this problem.

finally, i opened the pixhack and i found inside a little component burned.

i bought a new CUAV v3 controller and all works good.