Television and Home Theater

The video input jack on my Toshiba CF27G50 (about 12 years old) is not working properly. I have the TV connected to a relatively simple (HTB)home theater system and I often get no picture when I turn on the TV. If I turn or reinsert the video cable on the TV, that often fixes the problem. I have tried numerous new video cables and it doesn't correct the problem. Is repairing the video jack a complicated repair? Any other suggestions would be appreciated.

The picture-in-picture feature works fine against a background of 'snow'. I can't get a full screen pix. The TV is six years old. Any sugestions, please.

just got new sanyo t.v recently was watching it the other night n turned it self off now when i goto turn on with remote or on tv just makes the electricy click sound but no picture or light to the power on light. wondering if you may have an idea as to what seeing crapy warranty just ran out. some one said power surge but i dont think so any help be great thanks