Monday, June 20, 2011

LCD or plasma TV won't turn on or black screen?

This is a rampant issue, and it spans so many makes and models of flat panels right now, that I am going to post this as a tip so that people can find it more easily.

A while back, an electrolytic capacitor manufacturer that sells their product to a plethora of manufacturer got the electrolyte formula a little off.
Apparently they got the ratio wrong for a stabilizing agent, and these caps fail usually just after the warranty has expired on the product.
Some repair shops want up to $800 to replace the boards in larger plasma units. Well, that's a bit nuts because they can be repaired for about $25.
How you say? well, here's the deal...

There's a good chance you have failing electrolytic capacitors either in the power section or the inverter section or both.
Any caps in these sections that look bulged at the top, or bulged/leaking at the bottom need to be replaced.

If you repeatedly turn it on, eventually it'll probably stay on, but every time you turn it off, the TV will get harder and harder to start up until one day it just won't.
Some units will just click, others give the "7 blinks" of death.
Sometimes you have to do the opposite to start it up and unplug it for 5 mins, then try.

If you aren't tech savvy, find someone who is to help you replace these caps.

If you are handy with a soldering iron and can identify the power supply and inverter / FM section for the back lights, an inexpensive handful of capacitors will likely fix you right up.
Match the capacitance on the capacitors. Go over voltage if you can, and still have them fit.
IE - it's not a bad idea to replace a 10V cap with a 16V or 25V or even a 50V(if they physically fit the board), but don't replace a 680uF cap with a 500uF or a 1000uF (unless you are positive it's only doing ripple filtering).

Most of the caps that go are 10V at 470uF, 1000uF or 3300uF and are usually rated for 105 degrees, but the temperature rating isn't as important.

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