APM 2.5 does not connect via USB anymore

I’ve been flying with my APM 2.5 successfully for some months now. Everything worked perfectly. Since yesterday the USB connection does not work anymore. On USB and without other power the LEDs flash and the calibration seems to be working normally. But there’s no connection to the mission planner. The computer does not recognize the USB connection. I tried it on another computer with other cable and compared with other APM 2.5. I updated the software after the problem occured. Did not help. The problem is definitely in my APM. Any ideas please?

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  • yes ı have the same problem

  • Christoph, do you have the radio modems ? If so try to connect to APM that way. If that doesn't work my suggestion is to solder up the UART0 pins and connect the 3DR modem and see if you can establish a connection. This bypasses the USB/PPM which you may have either a:) blown or b:) the zener fuse blew and you are now being blocked from it. This doesn't mean your APM is dead by any means. I received my first APM from Udrones and it was broken on arrival, I was able to bypass the USB and direct connect via UART0. It allowed me to connect to APM and work with it, I could not flash any firmware updates but that made me confident it was still useable. Then I soldered up the SPI port and used my poulolo USB AVR to flash the firmware and I have a working APM 2.5 that the USB simply doesn't work. So it is possible that yours is not completely gone, however if my suggestions do not work then you will need some one to get on it with and osciliscope to see what is going on or send to 3DR to troubleshoot if they are willing too. 

    Best of luck!


  • Admin


    These are the kind of symptoms you get when the APM had been shorted out and the serial mux and some of the other components have been damaged. How does your APM responded when it is battery powered and in the manual mode?



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