Power will not stay on

There are several known issues that can cause that.

The top candidate is the main board, the next is the Y-Main board.

Here's a link for repairing the power supply board of LG 42PG20, which also contains a link to how to test your own board to see if it is good or not:

http://www.coppelltvrepair.com/p/716/lg-42pg20-ua-power-supply-board-repair-service

Hope this helps!

The problem with the set is bulged electrolytic capacitors in the power supply.

This will bge faulty capacitors in the power supply, Take the back of the TV and check the power board for capacitors that are bulged /swollon on top, they may also leak a brown like substance, usually they are around 1000uf / 10v

Change any that look suspect and if capacitor related this will resolve your issue.
Hope this helps

This is not good. Was your tv unplugged or just power button off when you left for vacation. PlasmaTvs are highly susceptible to damage from power surges caused by lighting. Leave unplugged for at least five minutes then plug back in and see if this helps.

Here's the number to HP case management 877-917-4380 ext.79, try this number and be firm that they need to fix this, I just had an HP plasma that was 3 yrs old replaced for free, no charge. Good luck

Hav 50 inch lg no pic but got sound wtf how do i fix it an there r 5 flashes b4 green light stayes on at the start

Our LG 50" plasma tv screen went black after a popping noise but still had sound, after great diliberations decided to take the back off and have a peek!
We unplugged the tv and tested the fuses (there were three we could see) one had blown, the one on the left as you look at the back of the tv it also has one above it. We wrote the code/seriel number down and took the fuse to the electrical wholesalers Maplin and bought a pack of 10 fuses for £1.29 replaced the fuse in the tv and everything now fine!!!!!!
Hope this might be of use to anyone whose lost the picture after a loud popping/snacking noise but still has sound.

Same thing for me. TV just turned off one day and won't come back on. LED flashes red. Someone said it's because a cooling fan went out. If I can't find someone to fix it I'll take it apart and tinker myself. 32" with dvd built in was barely over a year old.

no kidding? what is the problem so prevelant in this unit? obvious design flaw.