Turn on and stay on

Question

I have a Smart Plus Series, Phillips Magnavox, When I turn on the television with the power button on the tv the picture has black and white lines then turns off. I push the channel "up" button the tv turns on the about 5 seconds it turns off automatically. I tried pushing the "up" volume the tv turns on then about 5 seconds it turns off automatically. How do I get it to stay on??