I have a 2+ year old Panasonic 50" plasma (CT-20G8, CT-G2133, or CT-G2173). I started hearing ahum a few weeks ago. Now there is no audio, hum still there. I have other TVs hooked to the same incoming cable service. No problem there. I tried a few simple tests and it is TV, not cable issue. Is this a common problem? What is likely issue?

I have a Panasonic TX26LXD52 flatscreen TV and I cannot get rid of the sign "HDMI" in the left top corner of the screen when watching SKY HD Digital. It even records so. Can you please help?

Thanks Gaborjudit