BEFORE you plug in the flight battery, make sure Tx is on, crystals are sitting properly, and throttle at minimum and perhaps center all trims. Make sure the switches on the Tx are on the right position. Don't have my Tx at work here but IIRC 2 on the left are on lower position and the 2 on the right are on upper position. Also, on mine the throttle trim has to be about 5 notches below center at startup or the Rx LED would stay red. The Rx takes some reading at startup so all of the above has to be done BEFORE plugging in the flight battery. In normal startup procedures, the LED should flash red perhaps twice first. If the Tx is "talking" to the Rx properly, the Rx LED should flash green 3 to 4 times initiating the gyro. After that, the LED should stay green. All the while, leave the heli on flat ground and do NOT move it or any Tx controls. Any time you adjust the mixer proportional trim on the Rx, you have to disconnect and reconnect to make it effective. Other than that, it might be a genuine problem.