# 42lg3000 TV



## berts (Aug 4, 2012)

Hi,

I have a 42lg3000 LG television. It powers on and I have backlight. But the image displayed flickers along the Y-axis. Does anybody know which part to inspect / replace. Seems like a waste to bin it.

thanks


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## octaneman (May 13, 2009)

Hi berts 

Inspect the power board for bloated capacitors.


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## berts (Aug 4, 2012)

Hi,

Thanks for helping.

Inspected board, no sign of bloated capacitors. 

Next steps?

Berts


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## octaneman (May 13, 2009)

Using a DMM you will need to check supply voltages going to the main board and T-Con board. The voltages are written on the power supply pin outs that go to the main board and T-Con board. The voltages on average range from; 3.3v , 5v, 12v, 18,v.. These voltages need to be there for the monitor to work.


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## berts (Aug 4, 2012)

I haven't tested this as I dont know how. I do however have a digital MM. 

I thought I would show you my problem as a picture paints a thousand words.

https://dl.dropbox.com/u/74442358/2012-08-17%2013.09.04-1.jpg


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## octaneman (May 13, 2009)

It has the symptoms of a bad t-con board, the video signal is not being processed the way it should be.


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## berts (Aug 4, 2012)

That's what I was thinking although from what I can tell from Googling this problem the T-board may also be getting some sort of voltage spike from the power board. 

How would I test for this? I don't really want to be buying parts to test for faults.

Thanks again for your input, much appreciated.


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## octaneman (May 13, 2009)

To test the the voltage spikes you will need to locate the 5v,12v, 18v, on the power board and using your DMM see if they remain steady on the pins. If the voltages do not remain steady then its either a MOSFET or voltage regulator on a heat sink that is getting hot. For thermal issues techs use cold spray on the components while the board is powered up to pinpoint the failure.


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## berts (Aug 4, 2012)

Would a cold TV that has this malfunction from the start indicate that me freeze spraying components is a waste of time?


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## octaneman (May 13, 2009)

berts said:


> Would a cold TV that has this malfunction from the start indicate that me freeze spraying components is a waste of time?



No, Because the problem could also stem from the LCD screen itself. If the monitor is on standby mode when the screen comes on the components are not cold.


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## berts (Aug 4, 2012)

Hi, I have now replaced the Tcon board, the inverters and the power board. i also replaced the connections board (Hdmi , Scart etc) The Tv now powers on and works sometimes. I have noticed that if I tap the back and turn it off and on it works. Any ideas?


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## octaneman (May 13, 2009)

Check your ribbon connections carefully some connection is loose or there is a cold solder joint.


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