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Dan, Master Tech and Repair Facility Trainer
Category: TV
Satisfied Customers: 7201
Experience:  USAF trained; A.A.S Electronics; A.A.S. Education; Currently teaching advanced troubleshooting and repair for the DoD.
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I have an 42inch LG LCD tv. The sOund works but after a few

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I have an 42inch LG LCD tv. The sOund works but after a few seconds, the picture will blink out. I switch to another input and get the same response- but the picture may remain for a longer time using the DVD or avi inputs
Any ideas. Is this a fuse or bad circuit breaker? Is this worth fixing? Can I order parts and do it myself?

I had been able to switch inputs from the menu: now the picture input cycles off before I can change the input. I get a grey screen, with the avi input and then all goes black. Now more sound not more picture. But the lack of sound Kay be due to the lack of a sound input signal. The sound was working fine when I had the hdmi input sell Ted. I cannot get the tv back to this input.

There is no back lighting as farbas I can tell. But then again, I have nothing to input anymore.

model number 42 LG 30 UA
Product code : 42 LG 30 UA austljm
Serial 803mxzj01741
Thanks for the question. My name is Dan.

Yes, you can order parts for this TV... they're readily available. And you should be able to affect repair yourself if you have some mechanical and electrical inclination.

Questions for you:

- When the picture goes out, does sound continue?
- When the picture goes out, please make the room as dark as possible. Are the backlights working? The screen might look dark gray (glowing slightly) as opposed to solid, pitch black.

Kindest regards,
Dan T.
Customer: replied 6 years ago.

Thanks dan
the sound continues to work fine.
The screen goes completely out. No back lighting, no grey.
I have some limited skills- more theory than technical ability. But I can learn.


Ok, turn the TV on so you can hear the audio, then again please make the room as dark as possible. Then hold a flashlight very close to the screen and look for faint images, shadows, or movement of what should be displayed on the screen. You can try to bring up the TV menu, too... so you'll know what to look for. Can you see anything?

Customer: replied 6 years ago.
I am having trouble switching back to cable hdmi input. I plugged in my kids wii and now can't switch back. The tv goes on and displays the input (avi) that is selected and then blinks off.there is a sound that is a little like a modem that I hear which also cuts off when the screen goes blank. It is black. I see nothing but blackness.

Now the wi iis booting up to display an image....or sound.
So you turn it on and you see the selected input for a second, then it turns off and audio continues?
Customer: replied 6 years ago.
Yes, that is what was happening. Now I am no longer in an input mode that has audio so I can't tell. I can't get the imput back to hdmi so now I get nothing after a few seconds. Wnen the input was on hdmi, I still would get the sound signal because the tv is hooked up to my cable (verizon) box. I am on my blackberry for the 2 hours and away from my set and my computer.

Ok, let me know when you're ready to continue. You should be near the TV. No rush.
Customer: replied 6 years ago.
Hi Dan-

I am back home near my tv. When I was out my son played on his wi for a while until the picture went out. He said that the sound kept working. It is not working now.
Silver Spring, Maryland
Ok, now can you double check that flashlight test please?
Customer: replied 6 years ago.
The wii is working now..... Image and sounds. So I do not think the flashlightbtest is valid.
Wait for the picture to go black again... then use the flashlight. It'll go black again, just give it time. Let me know.
Customer: replied 6 years ago.
My son says he can see movement, (link ). I am having motor trouble than him.... Sound is on, faint shadows....hard to see......but something is there. It is picture any more...
Ok, thanks!

There's about a 90% chance you're going to need new inverters. Your TV has 2... master and slave. The inverters are, essentially, the power supplies for the CCFLs in the backlight panel. If they fail, the CCFLs don't get the proper voltage and can't illuminate. The master is part number 19.26006.414, slave is 19.26006.413 and they'll run you about $50 each from (they rebuilt/recondition then resell).

Now, there's a slight chance you have a faulty main power supply (4%) or that the CCFLs themselves have failed (1%)... but both of these would be much more rare. If you have a voltmeter handy, check to see if you have 24VDC leaving the main power board and going into the inverters. If you do, the power supply is fine and will be removed from this list.

Please click ACCEPT (even if you're a trial or subscription member) if you are 100% satisfied with my answer and plan on leaving me positive feedback (your acceptance is the only way I get paid for my work). A bonus would also be appreciated!

I'm sorry if my answer wasn't what you wanted to hear, but it reflects the most honest and accurate information available. I hope you take that into account when deciding whether or not to accept and leave positive feedback.

That said, if you aren't fully satisfied please do not accept my answer. Instead, let me know what else I can do for you!

Finally, please know that accepting my answer does not mean our dialog is over... you can still post follow-up questions or comments afterward.

Kindest regards,
Dan T.

Dan and other TV Specialists are ready to help you
Customer: replied 6 years ago.
Thanks for your help. I will give it a shot. For 100.00 it may be worth it. But If the price of plasma keeps dropping I may just get a new set..... If i can fix it, i may learn something along the way. ( I used to do some work for chungwha picture tubes from Taiwan. If I can fix a tv ( even a Korean one) I would get street cred.

Thanks again.......
Andrew c. aitken

Sorry for the delay... it was getting late last night. Yes... fix this yourself... you'll be happy you did, even if you replace it. Though for what it's worth, I would only get a plasma if someone gave it to me. LED (LCD) is a much more reliable technology... fewer things to go wrong.