Hitachi 50UX58B No sound

If anyone can get me pointed in the right direction on this....
I was layin back, watchin the eastwood marathon, then POP, no sound. Pic
is fine. There was no warning signs, buzzing, humming,
blips...nada...all I got now is a pop when I power the set on and
off...I am still watching, but using the surrond receiver for my audio.
I have been working in electronics as a tech for a while, but I never
tinkered with a TV set...and of course, the warranty on this thing was
for 1 year P/L, and it is just over 13 months old.
I might get my wife to cry on the phone to the warranty hq if I can't
find any obvious resolutions...

thanks in advance..
Boyd
dobbe @home.com