Be sure to call LG to confirm it's not a setting we can change. I only glanced through the manual and didn't see it. I made the assumption you read it all.
I recently purchased an LG 42LN5300 LCD HDTV with only an optical out port using an OTA broadcast and a sound bar to go with it that also has an optical in port. All was going well until I actually got back and tried to set it up. Turns out that the TV output is only in SPDIF Optical and the sound bar only accepts PCM optical. As I am using an OTA broadcast with an antenna, there is no way to change the optical output mode on the TV to PCM like you could on an STB. I already tried getting an optical to RCA (since SPDIF to PCM converters seem to be nonexistent), but it only accepted PCM optical input. Is there a recommended go-to converter for SPDIF optical to RCA converter box that will actually accept SPDIF optical? Is there a way to manually change the setting on the TV without an STB or an audio converter? The converter does not have to be RCA specifically, as the sound bar also has coax and 3.5mm jacks on it.