Lg 47LN400

[Jtroutt19]

This LG unit will flash on then the screen blacks out. No sound or any other signs of life. Upon inspection of the p/s board an issue with a transformer was found. New board was purchased and installed. Issue persists.
Any ideas would be great.

[budm]

Re: Lg 47LN400

Start by uploading good clear pictures of the whole backside of the TV showing how all the boards are connected together, I do want to look back and forth between this thread and your other thread with the wrong info.

[Jtroutt19]

Re: Lg 47LN400

Ok added pics of the boards

[dick_barton]

Re: Lg 47LN400

Is it a 47LN400 or 47LN5400?

https://www.youtube.com/watch?v=Bf5T2wwtydY

[budm]

Re: Lg 47LN400

I cannot read the P/N on the barcode stciker of that power supply/LED driver board, picture is not in focus.

[cliff_hootarski]

Re: Lg 47LN400

I believe it's this one, courtesy of Shopjimmy:

http://www.shopjimmy.com/lg-eay62810...upply-unit.htm

[johnboy1313]

Re: Lg 47LN400

After the backlights go out, use a flashlight up against the screen to see if you can still see a picture. This is almost certainly one or more failed LEDs.

[budm]

Re: Lg 47LN400

The set has two set of LED strings, so you need to check the DCV at those 4 pins (LE D+, LED -, LED +, LED -) of the LED connector using chassis the GND ref. for the meter.

[Jtroutt19]

Re: Lg 47LN400

OK upon testing the backlight power circuit these are the result. My test point was the rectifying diodes for each circuit. One side jumps to 180v and the other only to 100v. So I am assuming I have a backlight issue at this point. PS board number is EAX64905501 REV3.0