First off center your trim and sub trim.

On the bench turn on the receiver and watch the light, it should blink for 3 seconds them come on steady.

Move the throttle stick from idle to full and back and verify the light remains steady. While you are moving the throttle make sure not to move it side to side. If the light flashes in normal mode while moving the throttle find and inhibit REVO mixing (you didn't say what radio you are using)

If the above test passes flip to idle up. If the light starts blinking then you have different trim settings that are tied to your flight mode switch, find and set the rudder trim to 0 in all flight modes and start over. Also check do the throttle stick test to make sure you dont have revo enabled in idle up either.

Also verify your mounting tape is secure and that you are turning the gyro on and letting it boot to a solid light in HH mode before disturbing the helicopter. If you have the 9253 or 9254 servo also check that you have DS MODE ON on the little dip switches on top of the gyro.