Curtis,
I have a 5 yr old Plasma by Panasonic. I had the same issue and spoke to a tv repairman. He informed me that a new circuit board would cost around $175 and a new Panasonic Plasma would be $400 so it wasn't worth getting a new circuit board. I was able to use a "band aid" solution below that seems to be working for now. I'm probably going to have to purchase a new tv within the next 2 years.
Try the following:
Unplug the TV for 1 minute and plug into a different power circuit, if possible, separate from the other components. Turn it on and it should work.
Try taking out the back cover and use a compressed air cleaner to clean all of the dust off the board.
Avoid powering off your tv and quickly turning it back on. The blinking light issue will surely occur.
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I didn't see any fans inside the tv
crwdns2934271:0crwdnd2934271:0 curtis crwdne2934271:0
This model has two exhaust fans at the top of the set. I just replaced nine.
crwdns2934271:0crwdnd2934271:0 John Baird crwdne2934271:0
modelTH50px80u. yr:2008 .no cooling fans.
crwdns2934271:0crwdnd2934271:0 tlewin808 crwdne2934271:0