No sound on one channel MacPro

[Hannah Mackinlay]

Hi all

Any ideas on why my MacPro (15 months old) is not playing any sound on
one channel, whether you use the front or back jack plug outputs?

I have tried rebooting, checking the balance in sys prefs zapping
pram, but no improvement

They have an integrated sound card so I am glad i got it from J Lewis
with an extended warranty if it needs to go back as that would mean a
new motherboard i guess if the card is bust

Kind regards

Hannah