I have heard of the following fix

by Pepe7 - 6/7/13 11:32 AM

In Reply to: Samsung ht-tx500 home cinema by susatsniper

Unplug everything in back, except the power cable, and leave it so the device can cycle/reset itself. This may take several hours, FWIW.

My other thought is that it has something to do with HDMI/Anynet. Not sure if this is related to your actual device though. Try asking in the Samsung forums here for this info maybe....