I don't know if you have the original owners manual, so I am posting the pdf below. Everything that I have read indicates that your unit is a quality product. If your settings are correct per the manual, the manual states you should try resetting the unit per the instructions given on page 18. If that fails, I suggest you contact product support.

For Product Support Team Only:
1-800-229-1687
http://www.us.onkyo.com/


http://filedepot.onkyousa.com/Files/own_manuals/SN29401537A_LS-B50_UM_02_EN_130808_web.pdf