Question about LG 47LC7DF 47 in. LCD HDTV

3 Answers

Have audio but screen is completely black. no audio. Tv had been working perfectly for about 3 years. unpluged it for a couple of hours but did not help.

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3 Answers

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  • Master
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First, look at the screen in darkened room to see if you can see any slight glow from the screen, if it does, then the problem can be the T-CON (not getting the 12vdc) or the main logic board not feeding the signals to the T-CON board.
if not, next place to check will be the power supply module, make sure it has 24vdc which is required by the backlight inverter to work, the reason for not having 24vdc can be from bad DC filter caps (leaking/bulging top, high ESR) or short circuits in the inverter board which will cause the 24vdc supply to go into shutdown mode, so you may have to disconnect the power cable that feed the inverter board to see if the 24vdc will work without the inverter board hookup, you will need to apply about 3~4 amp of load to the 24vdc to make sure it can handle that. There are fuses on the backlight inverter boards also. So there is some troubleshooting you will have to do to find out the causes of the problem you are having.

If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

Failed TV and Monitors: http://s807.photobucket.com/home/budm/allalbums

Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague

Parts: www.shopjimmy.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.

Please post back what you find.

Posted on Nov 11, 2010

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  • LG Master
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Tv turn on now,have a picture flashes only a few sec. than died and have audio left only?Yes,than the tv have dead 2 long boards call the LCD inverter boards.These 2 long LCD inverter boards help the LCD 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.

Posted on Nov 08, 2010

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  • Master
  • 320 Answers

There must be a problem with your power supply board. Check for any busted fuse or components.

Posted on Nov 08, 2010

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