Question about LG RZ-20LA70 20 in. LCD Television
I have an lg lcd tv it powers up but has no picture or sound. it turns on by remote with a click sound but the backlight fades and it turns back to standby mode.
please can you help
SOURCE: Sony KDL40V2000 LCD TV not
There's a good chance you have failing electrolytic capacitors either in the power section or the inverter section or both.
Any caps in these sections that look bulged at the top, or bulged/leaking at the bottom need to be replaced.
If you repeatedly turn it on, eventually it'll probably stay on, but every time you turn it off, the TV will get harder and harder to start up until one day it just won't.
Sometimes you have to do the opposite to start it up and unplug it for 5 mins, then try.
If you are handy with a soldering iron and can identify the power supply and inverter / FM section for the backlights, an inexpensive handful of capacitors will likely fix you right up.
Match the capacitance on the capacitors. Go over voltage if you can, and still have them fit.
IE - it's not a bad idea to replace a 10V cap with a 16V or 25V or even a 50V, but don't replace a 680uF cap with a 500uF or a 1000uF (unless you are positive it's only doing ripple filtering, and even then, you should go OVER, not under the uF rating).
Most of the caps that go are 10V 1000uF or 3300uF.
I found some great videos of the procedure (for many Samsungs with the same issue) on youtube.
As you can see, this issue spans plasma TVs, as well as large and small LCD TVs and monitors.
The parts are cheap, and skill required is minimal.
Posted on Mar 25, 2011
SOURCE: LG RZ32LZ55
There could be two possible failures:
1. The backlights are defective (not a common failure for a 14 months old LCD) or the backlights driver/inverter is defective.
2. Power supply failure(very common failure on LCDs) will cause the symptoms you described.
Posted on May 22, 2008
no solution, yet... our tv is under warranty, and this is the 2nd time we are going to have to have the SAME problem repaired, and they replaced the whole "INSIDE" the first time!!! so, same problem, 2 different panels, must mean somethings going on, you crappy Sony, you! *shaking fist*
Posted on Jan 20, 2010
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:
Failed TV and Monitors: http://s807.photobucket.com/home/budm/allalbums
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Posted on Oct 21, 2010
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