[suicideneil]

You do mean an external UBEC right? In which case, you dont have to do anything! So long as the redwire is re-inserted into the Rx lead from the esc, you just have to plug it into the receiver like normal, and the built-in BEC of the MGM will power the radio and servos. If the toasted UBEC is still connected up, just de-solder it/ cut it off of where-ever it is soldered upto, and toss it in the trash.