I had the same problem when I first got my 990. I almost threw it out the window. To fix mine I did a System Reset (page 48 of owners manual) and also unplugged the 990 from power overnight. Then I configured the 990 manually. I'm not sure which one of those fixed it. I suspected it had something to do with the Automatic Setep.
_________________________
Outlaw Audio Model 990
Outlaw Audio Model 7500
Polk Audio RTi150, CSi40, FX500i, PSW650
Sony KDS-55A2000
Onkyo DX-C390
Toshiba HD-A2
DirecTV HR20-700
Philips Pronto TS-1000
Pics of My System