Most new TVs have a timer in them. So do most TVs sold in the last 8-10 years or so.

If you know that yours doesn't have a timer, then the TV must have a mechanical on/off switch for an outboard timer to work properly.

If your TV does have a mechanical on/off switch, then a simple lamp timer should suffice. You simply leave the TV power on and then set the lamp timer to activate it.

They are available at most hardware stores such as Lowes, Home Depot, etc.

This TV is not that old. It is a 13" Sansui. It has a push button for turning in off and on. I plugged it into a lamp timer. The timer turned it off but it would not turn it on. When I had an older TV that I had to turn the knob for off and on, the timer could turn it off and on without a problem. Any idea why the timer works for one and not the other?

The on/off button on your old TV makes a mechanical connection. If you unplug that TV while it is on, then plug it back in, it will turn back on. The physical connection inside the switch was never altered.

The on/off switch on your Sansui TV is an electronic one. If you unplug it while it is on, then plug it back in, it will not turn back on. Someone has to push that on/off button to make the electronic connection.

If you want a TV that turns on and off with a timer, then it looks like it is time to buy a new TV with an on/off timer built in.