On Sat, 25 Apr 2009 23:26:22 -0700, John E.
wrote:

What fails most commonly in inverter circuits in, for example, 18 inch LCD
displays?

http://www.lcdrepair.us/1800inverterKUBNKM045A.html

I know anything *can* fail. But is there a common, high-frequency failure
component in these inverters?

The transformer seems to be the most common problem. I've only tried
to repair about 4 of these. Three were visibly (under a microsocope)
burned and probably shorted when the insulation melted between turns.
One was open. All were repaired by replacing the transformer (usually
cannibalized from a similar LCD inverter).

I've also seen a few with fried switching transistors. However, those
were probalby the result of a shorted transformer.

Only once have I seen a dead CCFL tube (that wasn't broken by whomever
tried to repair it previously).

At this time, I don't consider it worth the time and effort to repair
the inverters. I might if I can't obtain a pull-out repacement on
eBay or if the LCD inverter circuitry was built onto the main driver
board, as is common on many LCD computah monitors.

Incidentally, I've been tempted to slop some thermally conductive
epoxy on the xformer in order to improve the heat dissipation.
However, without an IR camera, and more spare time, I haven't
bothered.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558