Originally Posted by
gigaplex
The Mamba X will power on without the receiver but won't arm, it'll keep beeping until the receiver comes online. The ESC doesn't need to see a receiver for the BEC power rail to go live. If it did, it would never be able to power on.
Also do not plug a battery onto the receiver when the ESC is connected unless you've modified the connector to disconnect the BEC.
I said some escs not "this esc". I've never owned a Mamba X so I don't have experience with this exact esc, but I have seen other escs that shut off the bec if the esc doesn't see a valid pwm signal after a short period of time. If the receiver is not bound to the transmitter the esc won't see the pwm signal and therefore will shut down the bec. This is why I suggested a battery for binding the receiver.