If you only have "a thin white line at the top of the screen", with no sound and no picture, how can you tell if you are changing the channel and how can you see the 'on screen menu'?

If you have no picture, no sound, but do have a visable 'on screen menu', then you have either a defective cable, defective tuner, or power to the tuner is missing.

This is strictly a guess, due to the poor symptoms listed.

good luck,

pw

Hi Pee Wee,
I have a Magnavox 20mt1331/17 T.V. and it also comes on and has a 1" white line that flickers for about 5 seconds and then nothing. I saw another post with a 25" T.V. and you led him to the resister 3340. I also saw the one where you took another person to the resister close to the 3 wire plug-in on the board on this Model 20mt1331/17. I ohmed out the resister and it was bad, so I replaced it. After I replaced it I turned on the T.V. and the resister smoked and opened. Can you tell me what this resister protects? It looks like the tube but I am not sure. Do you have any suggestions.
Thanks,
canman1355

I have a magnavox 20mt1331/17 (smart series) after i turn on the tv it takes a few seconds to lite up, but no picture its just blue with specks. it stray on for just a few seconds, and cuts off. I saw were u told some to replace resister #3340. I ckecked, but only have #3300-3318 on the board thats attached to the picture tub. what should i do. Please help.