Play around with the remote to see if any buttons are working correctly. Turn the TV on manually, and methodically press each one of the buttons on the remote while observing the results. Make note of which buttons are working.

If at least some of the buttons on the remote are working, then the batteries are fine, the remote is sending some commands to the TV, and the TV is responding to them. Two possibilities remain: either some of the buttons on the remote are bad, or the TV is not responding correctly when commanded.

If you have a second remote control from the same manufacturer, see if it works with your TV. If it work correctly with a second remote, then the problem lies with the original remote.

If a second remote also fails, chances are that the problem is inside the TV. That repair is possible but outside the scope of this repair guide.

If you have a second TV with the same brand, try pointing your remote at the second TV. If it works with this second TV, then the fault is with your first TV.

In my case, I discovered that my remote's Power button was ineffective, but that pushing the "TV" button on the remote turned the TV on. This told me that the TV was capable of turning itself on when commanded, so the problem lay with the Power button on the remote.