Hi my 50 inch panasonic has just developed black lines down it and the picture has gone grey it is on all channels hdmi, av1 ?

Hello nthomas

If you have a tube-type television, there is a problem with the vertical deflection section.
If you have a plasma-type television, there is a problem with the display output section.

Whatever it is, there is nothing you can do yourself but call in a repair man, or bring it for repairs to a repair shop.

Sorry to have to tell you that. This type of equipment can only be repaired by specialist technicians.

:)