I have a lg tv, I pushed the on button but no response I changed batteries also

Considering this is a costly set I'd advise taking it to a repair shop for service

Keep pushing the tv input button. This will allow you to cycle back through the other inputs and get you back to your source. When you pushed the button, you changed the source input.

Have you checked the fuse in the plug? Have you tried a different socket in your house?

Check your remote control first by using a camera, (phone is good). When you press the buttons the infra red LED will light up on your screen.

Try going in the settings and reset the tv. If that doesn't work contact the mfg.

I HAD THE EXACT SAME ISSUE ON MY LG TV. WENT THROUGH EVERY PROCESS REMOVE BATTERIES, UNPLUG ETHERNET CABLE, HOLD IN POWER BUTTON ETC ONLY TO FOND OUT IT WAS MY FIRESTICK REMOTE THAT WAS THE PROBLEM.
THATS WHAT WAS TURNING TGE VOLUME UP TO 100.
I CHANGED THE BATTERIES AND CLEANED THE BUTTONS AND TURNED IT DOWN. PROBLEM HAS NOW GONE.

Often removing the batteries resets the remote's circuitry.

If you still have a problem it is probably an activated button on the remote that needs to be freed.

If there is no visible damage press each remote button with a soft tip like a cotton swab and lightly wiggle it to pop the conductive plastic back to shape. Think of a wool hat with one side pushed in...you might need to take it apart. If you use a magnet to keep small screws and GO SLOW taking picture or notes as the pieces are plastic and are easily layered.

Do you mean changer is a remote control? Try to use manual buttons to see whether the TV work. If it does not response either the problem comes from the input/output controler or main board.

Make sure you push the TV button on the top of the remote before you push the power on button.