No picture tv sreen lights up half when you turn it on then goes black. voice is fine

You have answered your own question, someone needs to open it and find a loose plug or broken solder connection--if it reacts to being tapped on that is the issue- a physical problem inside.

Good news - don't worry about this TV anymore and just trash it out the moment you buy a new one!

Sounds like the backlight or backlight inverter is out on your TV.
You will likely want a seasoned professional to repair this for you assuming the TV is out of warranty.

There is a problem with the board of your television.That problem is in vertical section, theres a leak capacitor at the vertical section of the board.Its better to replace all the leak capacitor to make the picture back to normal appearance.If you can't do the repair or replacement of of capacitor try,Call a repair technician to do the repair or troubleshooting..Thanks..

sounds like your actual tv tubes blew causing no picture usually more expensive to fix than to just buy a new tv bad luck

Yes

This sounds like the power supply that feeds your back-light is going out. This repair should be done by a qualified technician

turns on and off by itself

I have a similar issue. Sometimes the entire screen goes black and sometimes only one-half - either the top or bottom half goes black. The only solution we have found is to gently tap the TV (usually the front side) and the picture will come back for awhile. It almost seems heat related as it only goes out after the first 10 minutes of use. There must be a fix to this.

it is due to loose contact near 1 anrena or cable socket. 2 cable wire loose. 3 loose contact near tuner. 4 tuner b+ line or agc line loose. 5 horihontal hold tunning is not proper.or control loose. hope this will help. good luck.