How to repair Mits TV?#TS-5053picture went dark but has sound?

I tried to use a dvd player also; but no luck either (hoped it was the cable)when you turn it on,normally you will hear the volume and then a click and shortly after,you had picture.Now there is no click and the picture is green for a second and then goes away(no picture), but there is audio the whole time.I left it off for a couple of days then tried again,this time i saw the picture(sweet)for around 20 sec and then did the same thing as before.I am a utility repair man,before i jump in; any ideas???