Need Denon A/V help please

[kothdvideo]

Installed a 2307 for a friend. Went to his house the other day to set up a universal remote & noticed a problem with his tuner.

On the other inputs, TV & DVD, the volume is just fine. -20 is nice & loud. But you can't hear the tuner until you set the volume at 0! So you can go +14 max and it's still not loud.

I can't think of any software setting that would make this happen.
Must be hardware. Anybody understand the schematics or bumf to know if this is a feature/problem?
So I guess I'll talk to Denon & ship it back (about 45 days old) unless anyone has any ideas?

Oh the fun of trying to pull it out, label & diagram (best backplane diags are Denon's adv. web site pdfs)
thanks