Hello Everyone!

I have a rcb6i which i use to connect to my megapirateng setup. (Quadcopter)
Recently i noticed a problem while starting up, my quadcopter tilts towards the sides and flips over. After repeated rebuilds and analysing each component, i found that the radio was giving a value of 1300 range instead of 1500 on the roll channel. (I have calibrated the esc multiple times)
And one more thing i noticed was the two channels were giving either the end values or the middle value and no intermediate values (yaw channel and roll channel).

Please do help me, this thing has been troubling me for many months.
(I can't fly cuz of it) 

IF that is the case do a test whether its the problem of radion or megapirate itself. If you have arduino with you load multiwii firmware into it and connect receiver and look in multiwii GUI.
Or take a servo connect it to receiver and check for every channel whether it skips any positions by slightly varying stick inputs.

Make a reset in radio.
To do this press enter , exit and up keys and power the radio on.

As instructed by Balakrishna Reddy, i connected the reciever to a motor via esc directly. Still i face the same issue. Motor runs on full value, half value or no value. No intermediate values.

@Voice of Deaf
I did as you told. The transmitter powers in and gives a blank screen. Then i tested the motors again. Still same issue.

May be calibration issues on both tx and the ESC...

Or use an new model in tx... Calibrate the radio also

So this really helped.
As told by you all, i reset and recalibrated the sticks on the transmitter again and voila!
It solved the issue.
I think something must have messed up it in the first place.

Thank you all for helping.