Tv screen blank/black and audio only until a few hours the screen appears

Its just the error of loose soldering joints on the main board of the unit.and it needs dry soldering on whole board that will make the loose components firm and then it will work as normal.if u have the cold soldering machine with tyour self u can do it yourself.and if dont have take it to the repair center to do it.

Usually when a tv goes black it means that it is toast. Unless it is new and under warranty it is not worth trying to fix at todays prices.

Please check when TV is in black screen state, filament / heater glows in CRT gun. If not, check lose connection of heater volt supply at board connected with CRT pins.

Ensure that it is not the receiver, or the cable.

If tv has only audio, then it is probably a cold joint on the flyback transformer, or a fault on the intermnal boards circuits.

Try hard reset .

Unplug your tv from power chord for 30 minutes and plug back the power chord to the tv .
This will reset your tv .

If your problem continues then you need to replace the convergence ICs