LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

[CapLeaker]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

At this point I'd really like to verify the LVDS on a oscilloscope, if there is any possibility for you to get the hands on one...
BTW: did you already try do disconnect only one of the ribbon cables on the Tcon that go to the LCD screen, then vice versa... in order to see if there maybe half of the screen comes up?

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

At this point I'd really like to verify the LVDS on a oscilloscope, if there is any possibility for you to get the hands on one...
BTW: did you already try do disconnect only one of the ribbon cables on the Tcon that go to the LCD screen, then vice versa... in order to see if there maybe half of the screen comes up?

I did that and there was no change. As for an oscilloscope, I don't have access to one.

For clarification, the LVDS is the cable that runs from the main board to the TCON, correct?

[dick_barton]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

For clarification, the LVDS is the cable that runs from the main board to the TCON, correct?

Yes, that is the cable.

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

Yes, that is the cable.

Awesome, thanks.

I know what an oscilloscope looks like but have never used one. For further reference, what would the oscilloscope tell me about the LVDS cable?

[budm]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

Please check the DCV (when TV is turned ON) at those test points I have marked: Black probe on the chassis.
VCC =
VCC18 =
VGH =
VGL =
VDD =
VCORE =
HVDD =

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

please check the dcv (when tv is turned on) at those test points i have marked: Black probe on the chassis.
Vcc =
vcc18 =
vgh =
vgl =
vdd =
vcore =
hvdd =

vcc = .026
vcc18 = .025
vgh = .022
vgl = .050
vdd = .018
vcore = .022
hvdd = .024

[budm]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

vcc = .026
vcc18 = .025
vgh = .022
vgl = .050
vdd = .018
vcore = .022
hvdd = .024

This is done with the TV powered ON? You have 12V feeding the T-CON fuse F1 but the switching power supplies are dead. Based on those Voltage readings you have made the T-CON board is dead at this point.
BTW, I hope you did the test correctly.

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

This is done with the TV powered ON? You have 12V feeding the T-CON fuse F1 but the switching power supplies are dead. Based on those Voltage readings you have made the T-CON board is dead at this point.
BTW, I hope you did the test correctly.

I'm pretty sure I did the test correctly. I had to run my pos. probe over a file to 'sharpen" it a bit as I wasn't sure I was hitting those small areas correctly.

In any case, I've got a TCON on its way.

EDIT: Yes, the test was done with the TV on.

[budm]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

OK, I hope that will be it.

[dick_barton]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

If you can provide feedback after fitting the replacement Tcon would be good.

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

If you can provide feedback after fitting the replacement Tcon would be good.

Absolutely.

[Diah]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

i hope you will remark this threat as SOLVED before its reach 100 post lol... this is manufacturing TV not repairing LG.. cheers up

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

i hope you will remark this threat as SOLVED before its reach 100 post lol... this is manufacturing TV not repairing LG.. cheers up

lol, can't argue with that.

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

TCON arrived, no change to the TV. Man...

This leaves the LVDS cable and the panel I guess.

[budm]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

So you still have 12VDC at the F1 fuse of the NEW T-CON but no DCV on any of those test points?

[dick_barton]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

Something is not right!!!!!!!
Do you flip up the tabs on the ribbon connectors to insert/remove the cables and then click them back down to lock the cables in place or are you pulling /pushing the flat cables into place???

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

WAIT! Oh man! I spoke too soon!! Hold on...

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

I'm seeing snow on the screen! Stand by....

[JDC]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

*whew*

Well, what did you think happened? When I put the new TCON in, I mustve not inserted the 2 strips in all the way into the panel, so I immediately posted the result here.

I went for broke and redid it all. Snow, glorious snow on the screen.

I intend to update the 1st post with the solution plus what I've learned from this.

Thank you all so much. I learned so much from this experience, mostly to take your time and use a magnifying glass.

EDIT: I guess I can't edit the first post. budm, dick_barton, diah, capleaker, and anyone else I missed, thank you so much for help me save the TV from the dump. I'm very proud of this!

[dick_barton]

Re: LG 47LN5200_U: PWR, MAIN, and all LEDs replaced, no picture

Well done. Now to show us a picture on the screen.