Question about LG 47LC7DF 47 in. LCD HDTV
When problems arise that kill both video and audio, it is normally related to the failure of the main power supply.
Nearly all modern electronics uses a 'switched mode power supply.'
They are more efficient while being much more complex and prone to failure but offer the added benefit of being designed so a 'downstream' fault will cause the supply to shut down to avoid setting fire to your home.
The supply itself will also cycle if it has an internal problem; once again, to prevent destroying itself or anything dependent on its outputs.
Supplies built a couple decades ago could only do this by blowing a fuse and there are conditions that can occur that would not blow the fuse but would allow overheating and further damage as well as fire.
You might try the following: Pull the AC plug from the wall and ignore the set for a day or overnight, then plug it back in.
There are literally millions of semiconductors in a modern TV receiver and sometimes, they trip and lock themselves up.
When that happens, removing all power from the unit will allow everything to return to a stable state and function as designed again.
If that doesn't help, I hope your set is still under warranty as this could be a multiple hundreds of dollars to repair.
The power supply is often on a separate board and unfortunately, component-level technicians aren't that common anymore so frequently, the board is replaced and the old one discarded.
Posted on Sep 14, 2008
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