Question about Flat Panel Televisions

1 Answer

No picture This 42" lcd tv has sound but no picture the backlight is working. is it the lcd controller power supply or main board?

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 2,267 Answers

The way to isolate the failure to the power supply would be to measure the voltages going to the backlight inverter board. If all the voltages are normal then is more likely a defective backlight inverter board or LCD controller board.

Posted on Jan 05, 2009

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

2 Answers

How can I fix black screen on Philips 42" LCD TV?


chances are it is cracked solder joint on internal board,
check link below, press the helpful button

http://www.repairfaq.org/samnew/tvfaq/tvtmmqcs.htm

Jan 24, 2016 | Philips 42PFL7422D 42 in. LCD TV

1 Answer

I have a Samsung LN40A450C1D TV that has sound but the backlight doesn't come on. I replaced the power supply board and same problem. I then replaced the backlight inverter. Same problem! I'm absolutely...


You have to check all the voltages, that comes from its main power supply board, to its back light inverter board. These is one pin at the backlight inverter board; comes from the main board; which controls the back-light inverter to start and off. This voltage is generated at the main board, and send to the back-light inverter board, as control voltage. It will be best to contact any service technician. If you wish to get some details; check the site linked here.Viewing it in "Mosaic" will make surf easy.
http://electronicshelponline.blogspot.com/

Feb 24, 2014 | Samsung LN40A450 LCD TV

1 Answer

Backlight issue


Check the incoming power supply voltage to its back-light inverter, from main power regulator board. Check the main power regulator board.

Oct 17, 2013 | Vizio XVT3D474SV 47 in. 3D LCD TV

2 Answers

The screen on my 42"


Hi.

If the screen is dark and there is still sound is usually because there is no power to the inverter board. Parts that cause this are inverter, power supply or main controller board. Power to the LCD panel should also be tested.

before declaring the TV faulty make sure that the problem is not cable settings or source selection.

Check if there is on screen display (the menu). If OSD is displayed, then the problem is either cable/source settings or a defective input circuit. Try also disconnecting power cord for ten minutes and then up to one hour. Power drain may fix temporary faults.

If all that does not work, then the problem is either inverter or power board. In some case the main controller board may also be responsible.

The inverter is a power board that converts DC voltage from PSU into AC high voltage, powering the whole backlight system. When there is a problem with the inverter the whole screen will be completely dark, while the sound keeps going on.
A problem with the inverter will mean that either inverter is bad, power supply is bad and does not power the inverter, or main board is bad and does not turn inverter on. Those are the three parts that must be tested when the inverter does not fire up ( sound and dark screen). Here broad description of how to test the three parts: Before proceeding...

From a user level point of view, all you should do is disconnecting power cord for fifteen minutes, and testing the TV with different connected devices and different cables (e.g. with a DVD, a receiver box, using a SCART and using HDMI).
Disconnecting power will allow a power reset that sometimes can fix temporary problems (usually not sound but no picture).
Testing different cables and devices excludes the chance of the problem being given by a bad cable connection.

If that does not work, call the manufacturer at the number listed in the owners manual. Verify warranty status (warranty may have expired 09/10). Make present to the operator that the TV is just out of warranty, and that the fault occurred without you making any wrong use of the TV. Some manufacturer in some case apply special condition.

Here replacement parts for most flat panel TV models:ShopJimmy.

See also:
PartStore

Regards.

Ginko.

Sep 13, 2011 | Philips 42PFL3603D/27 42 in. LCD TV

1 Answer

I have a X2Gen 42" LCD (MV42P) that has no picture


if there is no dispay in the screen atall then it has to be the screen or the unit controlling the screen which can be in the same unit as the screen sometimes also if you have replaced the power supply the main board and the controll board then there is either something wrong when fitting them or one of the units are faulty but i am thinking the screen mate i cant explain the sound it could be caused by the fact there is nothing to display meaning there is no picture being send and no sound,,,,


if you have any light atall in the screen when the tv is turned on this cant be the problem

it sounds like the input device is not inputing anything ie the hdmi or scart is not sending through and the tv and dtv are not sending this would explain why no screen and no sound because there is no sound or picture being send through and because the unit is broken there is not even any menus

Feb 24, 2011 | X2Gen HHE-MV42R 42 in. LCD HDTV

1 Answer

42 sharp lcd tv picture won't come on but the sound works fine


There are two places to look for the problems, the backlight inverter board and the power supply. Look at the power supply first since it is easier to get to, look for burnt parts, bad capacitors, etc.
http://en.wikipedia.org/wiki/Capacitor_plague
Please post back what you find.

Dec 08, 2009 | Sharp Aquos LC-42D62U 42 in. LCD HDTV

1 Answer

Sound is good but no picture


If there is no backlight (check it in a dark room - if there's a backlight the display will be emitting light, albiet still all dark) then you're looking to replace backlight inverter (or two of them, if it's master/slave) OR the power board. To know which of the two, measure the voltage on the cable that comes from the power supply to the LCD backlight inverter board - it has lots of cables but most of them are split in 2 groups - ground and positive usually 24V. It's fairly easy to see which are which, especially on the power board.
So if there's 24V there then it's the inverter(s) and if there's nothing then it's likely the power board; it's a little tricky, though, because the main board may turn off the backlight power - so make sure you check the voltage when turning the TV on from off and watching the read.

If there *is* backlight then you;re looking at replacing the tcon board or, less likely, the main board or, least likely, the cable between them.

Please rate my response if it helps.

Nov 06, 2009 | Vizio VO42L 42 in. LCD TV

1 Answer

Sharp Aquos HD black screen. Sound but no picture. Remote will turn TV on, but will not change inputs or do anything else. Happened suddenly.


Look at the venting grills to see if you can see any white lights inside, if there is no light, the backlight inverter board may have gone out or the main power supply for the inverter board is not working. If you do see the lights then the problem can be in the main controller board.

Nov 06, 2009 | Sharp Aquos LC-42D62U 42 in. LCD HDTV

1 Answer

LG LCD 42" tv sound but no picture


The backlight inverter board may have gone out or the power supply is not supplying power to the inveter board, those are the two places to check.

Nov 02, 2009 | LG 42LC2D 42 in. LCD HDTV

1 Answer

I CAN TURN THE POWER ON. THE SCREEN STAYS BLACK.


This TV has 2 main circuit boards (2 LCD backlight controlers): the Power Supply board may have fried the video board on it's way out ...
You can either arange to have the TV replaced under warenty if not have it serviced. In any case best of luck with Vizio support line.

Everyone bought this TV because it was so cheap... now we find out why: Vizio cuts corners on everything from engineering to support!! All brands are not created equal. Sometimes you get what you pay for.

Feb 09, 2009 | Vizio Gallevia GV42LF 42 in. LCD...

Not finding what you are looking for?
Flat Panel Televisions Logo

Related Topics:

299 people viewed this question

Ask a Question

Usually answered in minutes!

Top Flat Panel Televisions Experts

The Knight
The Knight

Level 3 Expert

68157 Answers

Donald DCruz
Donald DCruz

Level 3 Expert

17129 Answers

Jaime Hernandez

Level 3 Expert

2267 Answers

Are you a Flat Panel Television Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...