What would cause a TV to have great sound but no picture?

SOURCE: sound no picture, which component is tcon board? where all audio/video/cable/hdmi plug in to?

for bn94-00963b go and change your backlight inverter

SOURCE: sound no picture, which component is tcon board? where all audio/video/cable/hdmi plug in to?

I have LNS4692D. Returned from vacation, turned tv on - no picture. Tried turning tv off for 4 hours- nothing. Symptoms are: tv is on - no picture , just sound; menu doesn't show, volume bar doesn't show;E.Saving is working - the backlight is changing from lighter to darker.
Found this website and ordered T-con, otherwise known as the LCD panel driver board, p/n# Bn8101286a ( thanks premtech) from partstore.com for $124. Part number BN81-01286A A/S T-CON Board.
Installation:
1.Remove plastic cover. There is an arrow for each screw that needs to be removed. Make sure to unscrew pins next to VGA port. I've spent some time trying to figure out what else is holding the plastic panel until I found this pins.
2. Remove big metal shield in the middle of tv that is covering main components. This shield is being held by small black screws all around it.
At this point you will see cover of T-CON. Here is the picture
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=118863&d=1220531321 (thanks ldac9). Do not attempt to remove that cover yet. Proceed with a next step

3.Remove metal panel that holds main components. Locate big chrome screws that have arrows pointing to them and unscrew them. Remove 2 more screws on the bottom of the panel that holds it together with a box for cables. At this point the main panel will be lose
4. Carefully start lifting the panel. You will see that there are connectors going from components on the panel to components on the lower panel and T-CON. Carefully unplug these components and raise the main panel.
5. Remove 4 screws that holds T-CON cover. Pull the cover so that T-CON is completely exposed. The cover is connected by thin alluminum , don't hesitate to pull it , but don't rip it out.
6. Once T-CON is exposed you will see 2 red ribbons. I've spent some time to figure out how unplug those from old T-CON board. Here is the suggestion. Don't try to pull it out. All you need to do is to lift small plastic lever that is part of a connector. Then ribbon can be slided out. If not sure what to do, see how this is done on the new T-CON. It has a principle of buckle on airplain safety belts.
7. Remove old T-CON and install new you.
8. Follow reverse order.

I've never fixed TV before , but this was totally successful project.

SOURCE: how hard it is to replace by yourself main board Samsung LN-T4065

You need to do some more diagnosing of the problem. If you get sound and change channels take a bright flashlight and place it again the screen. Look for an image around the edge of the flashlight.
If you see an image that means the LCD controller board (TCON) is probably good.

The problem is probably one of three causes;
1) Inverter board is bad
2) CCFT (cold cathode fluorescent light) are bad.
3) Power to the inverter board is bad. You can also check the connectors.

SOURCE: my vizio tv,VX37LHDTV10A darkened and shows

This may work for you. My Vizio went black except for the blue channel rectangle in upper right corner; I couldn't change the channels or power off. I called Vizio, was told I needed a hard reset, and this fixed my problem: I unplugged the TV; held down the on button for one minute, then plugged it back in. It works fine now.

SOURCE: I have a NS-LCD37-09 tv. No picture or backlight

Your main board is faulty. I've done several of these but haven't been able to figure out which component is actually bad these yet. I've simply had to replace the board itself, and it fixes it every time. One thing you can do to get your backlights to come on (and so you know I'm not Jive'n you) Is unplug the three wire bundle that spans from power supply to main board. This will usually make the backlights fire up. I even had one that after I left it that way for a minute (with the backlight on) it suddenly started working again! But this was short lived. :-(
One time I even tried recapping the entire main to see it that would fix it. It did not. I think it might be something to do with the small chip labeled SL37HA37. It's a 16 legged bastard near the 3-wire plug I told you to pull. It's that or possibly the bigger IC near it that has a heat sink on it. The ball grid array solder joints may be faulty. Just guesses, if any smart guys out there figure this one out, be sure to tell the rest of us please!
Thanks, Chris Boise LCD www.boiselcd.com