A:AnswerYes, it is a known issue. I purchased an open-box version and there was a loud hum from the TVs power supply transformer when the backlight was set to anything less than 100%. Users report the hum goes away when the backlight it kept at 100%. I exchanged it for an unopened box and so far there is no hum at all.
Cross my fingers.
A:AnswerYes it does. When my blu-ray player is connected to any of the HDMI inputs, it is able to pass a dolby digital signal to the receiver through the optical output on the TV.