Was flying my rex yesterday when the motor stopped mid flight. landed. Checked & had a wire going to the motor broken. Fixed. Put back in the air for about 1 minute. Quits again. This time no broken wire, but it acts the same (kind of surging but won't turn). Is it the speed controller or the motor?

sounds like the esc has gone bad.. i had the same problem.. so i took the esc out of another bird i had and tried it and it worked fine.. my problem was the blades would spin up real good at first and then slow down to a complete stop.. jake.

Could be either one, if you have an extra esc try that first. I had the same issue and swapped out my esc cause I had an extra layin around but that turned out not to be the issue, it was one of the wires inside the motor case that was bad.