Well, no sound no picture = power supply unit
Sound no picture= flyback
picture no sound =tuner/audio logic
You get my drift?
You power supply is bad you replace it you got another new TV, with this digital conversion hitting I would rather advise you to get a nice flat panel and donate that one to Goodwill
Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edwy_1a56970cf1ea4620