a. If utilizing an Antenna, check the Connection, and adjust the Antenna  Position or Direction. Also, try a different channel. 
b. Check for nearby electronic equipment, fluorescent lights, or engines (car, motorcycle) that might cause interference.

a. Check if Power Cord is properly inserted into the TV and into the wall socket. 
b. Check if the TV is plugged into a switched outlet that is turned off. 
c. Check if the TV Power is On. If utilizing a Video Source Device (Cable Box, Satellite Box, Blue-ray Player, etc.), make sure the device is plugged in to a working outlet and turned on.

a. Check the Volume Level and Mute Button 

b. Check the Audio System or Video Source Device

Check for good batteries and that the batteries are inserted correctly.

Check the applicable Owner’s Manual posted.