onn LE32LCD08021D

[t1412]

morning fella's i'll try explain this fault here goes, this couple have an onn tv model number LE32LCD08021D, it connected to hd sky box, the problem, they can't seem to mute the tv when the adverts come on and sometimes the  volume doesn't work. they have rang sky for remote codes they have tried all of them, also the tv remote does the same, i'm thinking mainboard or epprom fault, thinking caps on chaps, thanks for your time

regards
shaun