Disklavier

I have the cable installed  works fine as a player and self play.

Problems:

1. Mounting bracket not there.. will call the dealer. Anyone have the part number?

2. I cannot have Piano  and  Voice at the same time.  On the DKC55RCD  there is a "Piano ON/Off"  in the voice menus, a setting that I have not found in the menu structure of the DKC850

3. And now the biggest issue.  Amplifier HUM.. and Volume of the Voice or CD Audio being played via the AUX in..  With nothing playing there is the hum and there is amplifier hiss,  and when audio CD or VOICE are played I cannot get a quiet volume..  -10 on the DKC850 is still what I would call a "normal"  volume level.. aka 5/10  volume setting.  The Volume dial for the DGT7A (located to the lower left)  does not effect the volume of sound produced from the DKC850..

Thanks for the help...  Is there a Tech support Number to call for Yamaha?