Vizio L42HDTV LCD

This is a common problem for this kind of TV.

You just put in a new PCB master and slave board.
Or use a repair-kit and replace the defected parts on the board.

INVERTER BOARD NUMBERS REPAIR KIT NUMBER

Master - 6632L-0470A PNEL-T707A KIT63

Slave - 6632L-0471A PNEL-T708A KIT63

As used on the LG / PHILIPS LCD PANEL TYPE: LC420WU5

Examples of models that use this panel:

• PHILIPS 42PFL7662

• PHILIPS 42PFL9900D10

• PHILIPS 42PFL5332D

• PHILIPS 42PFL7332D37

• PHILIPS42MF337B/37

That sounds like an inverter problem. Check the capacitors on the inverter boards. There will be two on each board. The master inverter will be on the far left side, and the slave will be on the far right side. You will have to remove the metal covers over the inverter boards. Should be 4 small phillips head screws. If the capacitors have bulging tops, replace them.

Check the capacitors on the master/slave inverter boards. I just repaired a Vizio VW42LHDTV10A with the same problem. Cost to repair $2. The master and slave inverter boards should be on the far left and far right sides of the TV set. They both have metal covers installed over them so you will have to remove the covers to access them. I'm willing to bet the tops of your capacitors are bulged.

If this set is under warranty you should return it to get it fix/replace. (Being this old it probably isn't.)
If not then;
This sounds like the inverter/backlight board has failed.
This board controls the back-light for the set.

IF YOU KNOW HOW TO WORK WITH ELECTRONICS REPAIR or have a friend with knowledge/skill you can fix it.

>Unplug the set.
>Remove the back cover.
>Remove the shield cover over the inverter board(s).
>Unplug the cables connected to the board.
>Remove the screws holding the board.
>Put in the replacement board and replace the screws.
>Plug the cables into the board.
>Replace the shield cover over the boards.
>Replace the back cover.

When replace the circuit boards, avoid touching the front or back and handle by the edges to avoid contaminates and static

Get the part number that matches your board.

A search shows that this tv has two inverter boards. The one I show is the Master and the other is the Slave.
(The Slave inverter is sometime called Ballast board;)
If you do it yourself you can replace both to know you corrected the problem.

.You can get this part from several places.
http://magictvparts.com
http://www.discount-merchant.com/VIZIO-6632L-0449A-p/1215024.htm
www.shopjimmy.com
http://tvparts4less.com
eBay
etc


It looks something like;

Yes,this problems is the 1 or 2 long LCD inverter boards are dead.Replaced these 1 or 2 long LCD inverter boards,will solved this problems.These long LCD inverter boards help the LCD screen have a backlight to produced a picture.Tries websites like Shopjimmy.com,Ebay.com to buy those refurbishes 1 or 2 long LCD inverter boards for the replacement.

Does the backllght go out after a few seconds? Could still be a lamp or something else on the inverter boards. You could try used inverter boards from the same set with other problems (broken screen), Or a complete working backlight from another set but very delicate operation to swap the LCD display from one panel to another.

Disconnect the slave. If the set operates replace it. If not the main is bad.

sounds like a lamp failure.

If you are using a set top box this might be caused by turnig the box on at the same tie as you turn the tv on or slightly after you turn the tv on.  If you are using compnent or HDMI inputs the set needs to see the signal as it is turned on to know what formt the signal is in. 

I’m happy to help further over the phone at https://www.6ya.com/expert/dewayne_4a10eab6caecdb92