Hello everyone,
I’m troubleshooting an issue with my Pixhawk 6C Pro on PX4 v1.16.0 and would greatly appreciate some help.
The Problem: My vehicle connects to QGroundControl via USB perfectly. However, the moment I disconnect the USB cable, the main LED starts blinking red, and the vehicle cannot be armed.
The most confusing part is that I get absolutely no error messages in QGroundControl. If I reconnect the USB cable, the main UI is clear, and nothing appears in the MAVLink Console to explain the reason for the arming denial.
My Setup:
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Flight Controller: Holybro Pixhawk 6C Pro
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Firmware: PX4 v1.16.0
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Note: I am not using a GPS module.
Troubleshooting Steps I’ve Already Taken:
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I confirmed that parameters like
COM_ARM_CHKandCBRK_PREFLIGHT_CHKare not present in my parameter list. -
The USB connection check is already disabled (
CBRK_USB_CHKis set to197848). -
The I/O safety switch check is also disabled (
CBRK_IO_SAFETYis set to22027). -
The GPS check is set to warning only (
COM_ARM_WO_GPS= 1). -
I have tried everything to get an error message (unplugging/replugging USB), but nothing is ever displayed.
My Hypothesis: Because there are no MAVLink messages at all, I strongly suspect a power issue (brownout) when the board switches from USB power to the battery’s power module. It seems the PX4 OS crashes or halts before the MAVLink communication stack can fully initialize, leaving only the red LED blinking. My other guess is a corrupted firmware installation.
My Questions:
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Has anyone seen this specific behavior before (a red blinking light with zero error messages)?
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Is this a known issue with the Pixhawk 6C Pro hardware, or perhaps a bug in PX4 v1.16.0?
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What is the best way to diagnose a power brownout? Would you recommend trying a different power module first?
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Is there a way to get low-level boot logs if the MAVLink Console isn’t responding?
Thank you for any advice you can offer!