If I understand your symptoms right, when they power up and the red LED flashes that means

"Flashing Green OR Red while beeping = indicates speed control is looking for full throttle (green) or full throttle (red). If it continues for more than ~ 8 seconds, indicates speed control is seeing partial throttle (green) or reverse (red), increase endpoints on transmitter so speed control sees full throttle/reverse.


Increase your end points onteh radio and try again.