hello mga audio/video gurus!

i got an 8" lcd tv with tuner from abroad. it receives local vhf signals (though medyo malabo at chan 7 lang malinaw) but it can only get the video. di nya makuha ang audio. static lang. i've tried changing the audio settings na nasa manual (something like 6.0, 5.5, 6.5, etc) pero wala pa rin. pano kaya maayos to? may paraan ba na pwedeng mabago yung frequency nya to receive local channels' audio?

TIA