ESC and motor working only once connected to PC via USB


I am making a new setup with a new plane. I reflashed my Matek H743 - it happens the same thing with both arduplane 4.0.8 and 4.1. I configured that via MissionPlanner (ranges, calibrations and in parameters only disabled arming required)

Once I connect battery up, motor makes intro sound but only a single one. Receiver and transmitter connects - however it takes like 5-6 seconds once the servos start to respond. There is no any further sound of a motor and it does not react on throttle stick movement - only servos work. No USB connection at this point.

When I disconnect battery and as first power up via USB, open up a Mission planner, plug in the battery then motor play intro sound followed by few tones showing it is ready to work - and it does work.

When I bypass entire FB it works right away, it arms and spins.
I checked it on the separate set of a motor and esc and the very same thing happens.

In summary it seems, like only after connection to PC motor works. Any ideas why?

Had a problem here with FC - ESC combination. Changed the ESC and no problems anymore.

br KH

Only esc changed and nothing else in FC setup?
Second set of motor and esc that I’ve used to check if the problem exists, was working fine some time ago with same FC on another plane.

Settings in FC and TX unchanged, but learned again the other ESC with those settings.

cu KH

Thanks but that is simply esc calibration on esc level, it does not answer why my motor does not work without FC being plugged into pc

Sorry, I did not say, it’ll solve your issues.

I had some issues here and a simple swap of the ESC solved it for me. I heard in discussion, that every ESC should work with every FC, but obviously not with me. And maybe not with you also.
Those were two 20A HK ESCs and three CC3D revo minis. Just old stuff.
So in my eyes not worth doing any further trouble shooting.

br KH

One of the esc that does not work right now did work couple of weeks ago

I discovered new symptom today.

Matek H743-wing running arduplane 4.0.9

  1. Following sequence:
    SD card inserted into FC
    FC not connected into the PC
    I power it up (with LiPo) motor will make just a welcome sound (no seeking beeps for binding/arming) only. I can arm/disarm the the motor but it seems not to be connected.
    I need to re-plug the ESC cable on CH3 on the FC board. Then it binds, I can arm and run the motor.

  2. Following sequence:
    SD card inserted into FC
    FC is connected into the PC
    I plug the battery up (LiPo). Motor binds. I can arm and run the motor.

  3. Following sequence:
    SD card is not inserted into FC
    FC may or may not be connected into the PC - work the same both ways
    I plug the battery up (LiPo). Motor binds. I can arm and run the motor.

Seems like only unplugged SD card or PC connection allowes my motor to bind right away without re-connection of the ESC on the board. Tested with another ESC - same issue.
Can anybody explain what is happening over here?
I really cannot understand the logic.

P.S. I can record a short video if that explains issue better.

@Maciek_S did you solve this? I have the same issue. Seems like the h743 is too slow to boot up and the esc will not arm if the time between battery on and pwm signal ok is too long. I am guessing the sd card is slowing down the boot, thus why it works without it.

I have the exact same problem here. Flight controller may not be started at the same time as the ESC, otherwise it wont work. Did anyone manage to solve this issue?

Update 1: For me it isn’t the SD card though, as I don’t even have one installed, but the telemetry module. If I unplug the telemetry module on startup everything works fine, but as soon as it is “involved”/plugged in on startup the ESC needs to be powercycled to function properly. (As if it goes into a locked state)

Update 2: I can even notice the difference before the startup beep get’s played when I have the telemetry module connected / disconnected.