LG 42pc5d plasma television. As soon as you turn it on, it turns back off immediately. Started off with problem of turning it on and had sound but no pic. Once you turned it off and back on again, it would work perfectly. Now you turn on with tv power button or remote, and acts if it it's turning on but immediately goes back off. Power light goes from red to green and quickly back to red.

Hello,

It's the problem of overheating in the power supply board of the TV.on the power supply board of the TV there are few capacitors and IC.any of this IC is got short or may be weak.so due to this when you start the TV the current passes from electric outlet to the power supply board of TV.but when the current passes from that weak/faulty part at that time current gets stopped or slow and the board overheats and TV shuts off. this is a common problem faced by many other users too.the possible option to solve this issue is to check the power supply board by a meter and continuity tester and replace the faulty component on the board which is short due to which power supply board is getting overheated.its bit technical job but yes its not at all a costly repair to do or get it done by the technician. for required parts it can be easily available from local electronic hardware shop.

Hope this will help in solving the problem.......

Those were in the era of bad capacitors. You can take the back off the TV and inspect the tops of the capacitors for bulging. If they are raised at the top, they are bad and need to be replaced.