LG 4250DC - - 42" LCD TV Technical Manual page 99

mm_ Press the VOL or VOLUME button.
mini Sound muted? Press MUTE button.
mini Try another channel. The problem may be with the broadcast.
mini Are the audio cables installed properly?
mini Adjust Balance in menu option.
mmff A change in ambient humidity or temperature may result in an unusual noise
when the product is turned on or off and does not indicate a fault with the
product.
mini Check HDMI cable over version 1.3.
mini Check USB cable over version 2.0.
m_ Use normal MP3 file.
Adjust resolution, horizontal frequency, or vertical frequency.
Check the input source.
Work the Auto configure or adjust clock, phase, or H/V position. (Option)
m
z
x
99