Don’t throw away that Electronic Speed Controller until you make sure that it’s really shot.
I’ve had about 3 Speed controllers fail on me, and threw them away. A lot of money down the drain. This is usually caused by running more servos than the BEC portion of the ESC can handle and burning out the BEC portion. The motor controlling portion may still be usable if you use an external power source for your receiver and servos.
Most BEC's are rated to handle only 2-3 servos. Check the instruction sheet that comes with the Speed Controller. If your plane needs more servos than the ESC is rated for, you will definitely need a separate power source for your receiver and Servos. This can be either a Voltage Regulator, or UBEC (Ultimate Battery Eliminator Circuit).
if using a se prate power source, (voltage regulator) you must Clip the red wire out of the Speed control cable, and plug the control cable into the Throttle position on the Receiver. Only signal (Normally White wire) and ground (Normally black wire) are required to run the Speed Controller. The red wire provides the power from the ESC BEC circuit to the Receiver/Servos when the BEC is functioning properly.
The Voltage Regulator is plugged into Batt. position on the receiver.
With this setup I get sometimes 2-3 days of flying on one charge on the Receiver Battery, and even better there is always a regulated 5-6 volts going to the receivers and servos. Very important with the new 2.4 Spread Spectrum radio systems.
For about $40 you can get this package, and save the cost of a new Speed Controller.
Try it – You’ll Like it
Link to Some model Aircraft voltage regulators