Pixhawk fail to Power RX

Hi Everyone ,

I have been using my Pixhawk for the past 3 months and all works fine. today im having a problem with my TX and RX to bind . the only way to i managed to bind them using an external power supply.
any idea how to solve the problem .

Thanks

Perhaps some more information would help. What TX/RX are you using? When you say external power, do you mean BEC directly to the RX or you mean it will not work powering PH off USB, please elaborate?

Do you get any power at all to the RX from PH? If you have a multimeter, see if you are getting 5V between + and - on the RC port of the PH. Best to take the plug out of the RX and measure on the metal tabs on the back of the plug, rather than try put your probes on the pins of the socket on the PH, assuming you’re using servo plugs.