My hd tv has sound but no picture

SOURCE: No sound on NON HD channels

I had the exact same problem on a brand new Insignia 26 " LCD with DVD. Comcast tech was able to fix it by changing the Comcast box diagnostics. Here is what he did. Using the Comcast remote with the TV on - press power, cable, menu in that order. A comcast diagnostic srceen will appear. Select Additional HDMI options, then audio options. Change the audio options to L-PCM. Press power again to exit the diagnostics. That will fix it and you get to use the HDMI cable.

SOURCE: Sharp Aquos LC-65D64U Picture Quality

You need to change your TV's settings and enhancements. Directly from the store and out of the box, the settings are adjusted for easiest sell in the store. That means that:
Your contrast is cranked to 100. Move this down to 50 to 60.
Your brightness may also be cranked up high. Lower it to a level nearer the middle range but not so dark as to lose detail in the shadows.
Your TV is set on "Dynamic" or "Vivid" mode. Pick "natural" or "normal" or standard.
Your sharpness is at least on, if not cranked up. Turn sharpness down or off, and the same with "Edge Enhancement" and "VSM", all to off.

Lastly, I bet you upgraded size and you are now sitting too close to the TV. Roughly, if you are sitting closer than 130 inches (about 11 foot) you might do some rearranging or save some money and get a smaller TV.

SOURCE: Need help hooking up TV, BluRay, Home Theatre & cable box

I found that since the Panasonic TH50PZ80U TV has only 2 HDMI ports on the back of the TV, the best solution for me was to use component (red, blue, green) cables to connect the Home Theatre to the TV. I suppose I/you could connect the home theatre to the HDMI port on the front panel, but I don't want cables hanging out the front of the TV (personal preference). Unfortunately, I am no longer able to use the VIERA Link functionality available by connecting all Panasonic components to each other using HDMI cables, but I feel it's a small price to pay for the incredible picture quality acheived by using the HDMI cable to connect the HD Cable Box to the TV. I may yet be able to control everything using the HD Cable Box remote, but I haven't gotten that far yet but I've got Comcast coming on Saturday and hopefully they can let me know if this is possible: let me know if you have a solution.

So here are the components and the cable types used to connect:

1. HD Cable Box to TV: HDMI cable & Optical Audio cable
2. Home Theatre to TV: Red, Blue & Green component cables
3. BluRay Player to TV: HDMI cable

SOURCE: i have hd picture but no sound, tv says hdmi audio unavailable

I called Verizon and exchanged my STB from a QIP 6416 to a QIP 7216 and it solved the HDMI audio problem. This looks like the fix.

SOURCE: no picture on flat panel tv. has sound

Sounds like the digital control board, 6871qch038a Lg Digital Control Module subs to 6871qch038c. But that's just a first something I would check in this unit. Replace also capacitor C19, 630V big blue square cap very common failure for no video. You might want to shop this one thee are a host of problems with this unit that would certainly get some needed attention if a qualified tech were testing it and looked up the bulletins.
Good Luck!

William Rayburn, CET
Premium Technologies