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

[JDC]

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

this is yours first post, why don't bring the original main board back and tell us do you have SOUND via HDMI or others input signal ??

I hear static (snow) when I turn it on.

[budm]

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

So you should then have 12V dc on that side when you switch on.

Very confusing at this point since it does have 12V to the LVDS connector then if that line filter is not bad on the main board. I wonder now if he is having measurement error and we are just chasing tail due to wrong data.
He needs to check the resistance between that inductor against both ends of the SMD fuse on the T-CON to make sure it is connected all the way to the T-CON board.

[Diah]

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

I blindly replaced the power board and main board. No change..

this is yours first post, why don't bring the original main board back and tell us do you have SOUND via HDMI or others input signal ??

[dick_barton]

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

So you should then have 12V dc on that side when you switch on.

[JDC]

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

L1100 shows .001 ohms (with neg probe on one side, pos on other, TV unplugged).

[budm]

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

Okay, I need to slow down.

Given the pinout you put into my picture:

off

Pin 1: .006
Pin 2: 0
Pin 3: .005


ON


Pin 1: 1.784
Pin 2: 12.11
Pin 3: 12.11

So pin 2 is the output pin and it shows 12.11V so the switched transistor is working, now as I request the resistance reading of L1100. What resistance do you get, <1 Ohm? Right now I suspect that L1100 has open circuit.

https://www.badcaps.net/forum/attach...0&d=1461687797

[JDC]

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

Okay, I need to slow down.

Given the pinout you put into my picture:

off

Pin 1: .006
Pin 2: 0
Pin 3: .005


ON


Pin 1: 1.784
Pin 2: 12.11
Pin 3: 12.11

[JDC]

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

Where are the pin numbers?
TV off
Pin 1 = ???
Pin 2 = ???
Pin 3 = ???

TV ON
Pin 1 = ???
Pin 2 = ???
Pin 3 = ???

I posted it as if you were looking directly at it. Given that, Pin 1 is the upper left pin, Pin 2 is the upper right pin, Pin 3 is the center bottom pin.

As for the -14.44, I measured Ohms while the TV was plugged in and on. I now know that was incorrect to do.

[JDC]

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

Do you know how to use the meter? -14.44 is what? Volt or Ohms, and are you measuring the Ohm when TV is plugged into the outlets? Is that the way you also check the fuse on the T-CON?
No power should be applied to the TV when makes resistance checking.

So when checking resistance, does that mean unplug the TV or it being in an OFF state is okay?

[budm]

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

Where are the pin numbers?
TV off
Pin 1 = ???
Pin 2 = ???
Pin 3 = ???

TV ON
Pin 1 = ???
Pin 2 = ???
Pin 3 = ???

[JDC]

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

how about q409 that have marked for you to test pin 1~3?
https://www.badcaps.net/forum/attach...0&d=1461687797

off

.005 .006
0

on

12.11 1.784
12.11

[budm]

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

BTW: 'Quote:
Check the resistance between BOTH ENDS the inductor L1100 to the T-CON fuse to make sure it has <1 Ohm resistance.
See attached. Are you referring to the circled component? If so, it measures -14.44 with every combination of probe placements (wanted to be thorough). Not sure I did this right.

Do you know how to use the meter? -14.44 is what? Volt or Ohms, and are you measuring the Ohm when TV is plugged into the outlets? Is that the way you also check the fuse on the T-CON?
No power should be applied to the TV when makes resistance checking.

[budm]

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

How about Q409 that have marked for you to test pin 1~3?
https://www.badcaps.net/forum/attach...0&d=1461687797

[JDC]

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

LG EBT62421329 (EAX65049105(1.1)) Main Board for 47LN5200-UB
http://www.shopjimmy.com/lg-ebt62421...7ln5200-ub.htm

Is this your main board?

Looks to be it.

Check the resistance between BOTH ENDS the inductor L1100 to the T-CON fuse to make sure it has <1 Ohm resistance.

See attached. Are you referring to the circled component? If so, it measures -14.44 with every combination of probe placements (wanted to be thorough). Not sure I did this right.

Check the DCV (ref. to chassis GND) of all 3 legs of Q409 when TV is OFF and when TV is turned ON.

Are you referring to IC409 on the main board? If so:

OFF
1.840 0
_________

.023

ON
3.42 0
________

3.74

"While the TV is on, placing the neg. probe on either side of TCON's F1 fuse, and the pos. probe on the very first pin (on the left) on the still connected TCON cable, I get a reading a 12.13 VDC."
BTW, the readings should be done with Black probe to the chassis GND, not on the parts.
Fuse shows <1 Ohm for sure?

ON and OFF shows 00.3

[JDC]

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

O.k., you measured GND, 12V, 12V GND, 24V, GND, 3.5V, 3.5V and PWR-ON.
Where are the GND, NC, 12V, GND, 24V,GND, PDIM2, PDIM1 and DRV-ON measurements?

While ON:

GND: 0 GND: 0
12V: 12.13 N.C.
12V: 12.13 12V: 12.13
GND: 0 GND: 0
24V: 24.47 24V: 24.47
GND:0 GND: 0
3.5V: 3.52 PD1M2: -.001
3.5V:.52 PD1M1:.984
PWR-ON:3.111 DRV-ON:1.010

[budm]

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

LG EBT62421329 (EAX65049105(1.1)) Main Board for 47LN5200-UB
http://www.shopjimmy.com/lg-ebt62421...7ln5200-ub.htm

Is this your main board?
Check the resistance between BOTH ENDS the inductor L1100 to the T-CON fuse to make sure it has <1 Ohm resistance.
Check the DCV (ref. to chassis GND) of all 3 legs of Q409 when TV is OFF and when TV is turned ON.
Pictures provided by shojimmy.

"While the TV is on, placing the neg. probe on either side of TCON's F1 fuse, and the pos. probe on the very first pin (on the left) on the still connected TCON cable, I get a reading a 12.13 VDC."
BTW, the readings should be done with Black probe to the chassis GND, not on the parts.
Fuse shows <1 Ohm for sure?

[JDC]

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

If your backlight start and the panel stay black is T con problem.
Usualy this symptoms happen to samsung tv but the sound works.
Try to heat the main processor and see if you have picture untill he cools .
Also check the regulators near processor specially the 5v and VCC.
If nothing happen your tcon is faulty.
To test Tcon jump 12v from SMPS to the Tcon fuse.Disconect the LVDS cables Jump VCC 3.3v to the LVDS(CN1) connector ground pin.Aply ac to power supply, patterns of White, Red, Blue, Green
should appear on the screen.Voltages can be read at the ribbon connector or at test locations on the board (typical 16.74V, 3.3V, -5V and 28V)

This is good information. I'm not sure if I'm brave enough to try it yet. Thanks!

[JDC]

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

While the TV is on, placing the neg. probe on either side of TCON's F1 fuse, and the pos. probe on the very first pin (on the left) on the still connected TCON cable, I get a reading a 12.13 VDC.

[JDC]

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

yes, he is.

???

[CapLeaker]

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

yes, he is.