On my Insignia LCDTV26 I have almost 3" of black screen on the right and left side of the picture.

If it is left side/ right side problem it can be the tcon board or the connection to tcon board.

If you have tried using different input devices, looked for loose contacts
in power outlet, RC Jack, cable and connectors, the TV might need service.

the ratio you speak of is the 4x3 and the set may have locked on it--If you have not tried to: unplug the set from power for a while and plug back in to see if set will reset itself.

I presume you went into customer menu and checked to see if you have the option to change from 4x3 to full or 16x9.

Hello,

Problem is in either power supply or the Y-Sustain board.

The Y-Sustain is a relatively large board out of which go connections to the side of the display; it's therefore closer to either the left or the right side of the display, has at least one rather large heat sink on it and fat power cables connecting it to the main power supply.

Often there are fuses on that board - one or more. Check those.

if they are blown you can try to replace them, but expect them to blow again - usually the whole board needs to be replaced.
I hope this will help to solve the problem...

Having same problem. Smacking it or applying pressure often works. Extremely annoying (inconvenient) that a nearly $1000 machine breaks down very soon after one year ( how long the warranty is, of course)

Tv turn on now,u only have a flashes of a picture for a few sec. than died have sound left ony?Yes,the tv have 2 long boards call the LCD inverter boards,one on it left and one on it right sides.These 2 long LCD inverter boards are dead.These 2 long LCD inverter boards help the LCD picture screen panel to have a backlight to produced a picture.Tries websites like Shopjimmy.com,Ebay.com to buy those refurbishes 2 long LCD inverter boards for the replacement.

could be a panel driver (if it looks like lines) or just poor digital connection(most of the time) could be in the tv (the connector is faulty) or your cable.

I've never have actually tried fixing these sets. Best Buy usually has the geek squad replace them with a LG product. If unplugging, and resetting doesn't work hopefully, they'll let you do the same. It has to have a service adjustment.

is it posible the menu settings have been changed, go into menu select picture check to see what mode it is on ie; 4.3 16.9 etc, set to wide screen 16.9

I have the same problem with my insignia.

The screen was all "pixel-ated" .

Sometimes the picture would be clear and then it would go all fuzzy.

One day in frustration I kinda smacked it. Guess what? ... the picture cleared up.

Since then about once a week I kinda have to smack the right or left side jst to the left or right of the screen.

Good luck.