Hi ,
For my Drone i am using FlySky FS-T6 6CH Transmitter with FS-R6B Receiver , for long time i had not used my transmitter & Now it is not powering On(Even After checking it with Fresh Set of Batteries)

I am Mechanical Engineer with Limited Knowledge of Electronics Stuff

Can some one please tell me step by step  diagnosis to identify the problem (which part is not working)