My Zenith t.v was working fine now when I turn it on the screen is completly black but there is still sound??

Answer 1

The fact that you have sound means that the horizontal and high volts circuits are ok because the volts to run the sound are taken from the eht transformer !!

With the room in darkness look into the back of the TV ! you should see a glow in the tube neck !!
If there isn't one then there will be a bad solder joint either on the CRT neck board or where the wires are connected to the main board , start by resoldering the neck board or get help to do it .
Cheers Pete

Answer 2

Assuming this is a standard CRT (picture tube) TV, you may have lost the high-voltage circuit to your picture tube. Or it could be any of the video circuits that are in line from the TV tuner to the screen.

If the input to your TV is a video cable (single RCA cable to the video input), you may have a problem with the video output from whatever device it's coming from (cable box, for example) or the cable somehow came loose.

Someone also might be messing with you and turned the brightness all the way down on the TV.

Press the menu button on the TV remote to see if any menu options appear. If the TV is working and it's one of the other problems I described above, you should see the menu options appear on the screen. If you still don't see anything, the TV is broken, and will either have to be fixed or replaced.