My 2002 Panasonic 32" Tv will power on but no picture appears. After warmin up and tapping the sides of the TV the picture will appear but occasionally will go off.

Any ideas of the cause and if it's worth fixing.

Steve,

You didn't describe how the picture appears and disappears - fade in and out, or appear/disappear suddenly, perhaps accompanied by streaks and 'flashing'? And you didn't say what happens to the sound when the picture goes on/off.

Nevertheless, it sounds like the typical symptoms of a 'dry joint' on one of the printed circuit boards. A dry joint is a solder joint where the solder has not properly wetted both conductors being joined. As a result the connection relies on physical contact between the two parts, which can be intermittent, and affected by temperature (expansion) and vibration (hitting the TV).

A competent TV technician should be able to fix it in less than an hour. Mind you, competent TV technicians may be hard to find these days (depending on where you're located), with the throwaway/board replacement mentality that afflicts modern technology [though I have to say trying to fix (at the component level) printed circuit boards using surface-mount technology is a lot more difficult than the through-hole technology of old!]

Daniel