I bought LG 60PZ550 plasma 3D in 2011 now in 2017 the sound audio is out. I unplugged the tv for 5 min held pwr button, tried connecting a sound bar via optical cable still no sound out, Please help

SOURCE: LG LCD/DVD TV no sound on TV - DVD works fine with sound!!!!

HERE is the servce manual for this TV

SOURCE: NO AUDIO/set up problems

For this Sony, you have to use separate audio cable(s). Either optical in BD or Digital Audio in DVD (single coaxial cable will do the trick) I bet the display says UNLOCK. I had the same problem, very dumb.

Good day!

SOURCE: connecting lg tv to two external speakers

Yes,
depending on how many speaker you intend to run will determine the type of amp you will need.  Set the output on the source unit to optical out.   Connect the optical cable to the amp.  Connect the speakers to amp.  turn them all on and select the iput of the source unit on the amp and enjoy.
good luck
chachig

SOURCE: Lg Plasma Display settings keep switching

When you boot up your tv for the first time, you get to choose between home and shop-mode.
In your case, he TV is set to "shop-mode".
Then it will go back to factory settings after 5-10 minutes. (so that customers won't mess up the settings all the time)

So change the settings from shop to home, and your problem is fixed!

SOURCE: Trying to connect an ipod to LG plasma tv via USB

Hey - I'm in the same boat, did you get it working? I connect and get the USB menu up, but the tv says that the file is corrupt, even though the iPod works fine when it's not connected to the tv.