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

[JDC]

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

Did you manage to follow the wiring back from the Tcon fuse back to any component on the main board. You said earlier that the 12V on the Tcon fuse was missing?

I haven't yet, no. You are referring to the F1 fuse on the TCON?

[dick_barton]

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

Did you manage to follow the wiring back from the Tcon fuse back to any component on the main board. You said earlier that the 12V on the Tcon fuse was missing?

[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?

Yikes! I see what I did wrong now. I'll get back to you. Thank you for being patient.

[CapLeaker]

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

ON

-.009
12.13
12.13
-.01
24.48
-.011
3.51
3.51
3.104

OFF

0
.009
.009
0
.006
0
3.55
3.55
0

Attached is a diagram for the connection from the power board to the main board. It says:

P201

GND GND
12V N.C.
12V 12V
GND GND
24V 24V
GND GND
3.5V PD1M2
3.5V PD1M1
PWR-ON DRV-ON

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?

[charis]

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)

[JDC]

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

from yours T-CON photo it show to me the left ribbon cable not correct sitting at the panel socket., take them both out and check the Gold pins of them, then reset them correct, as they labeled with hand writing they seem had story.

Reseated, nothing out of the ordinary I could see, still no change. Thanks anyways.

[JDC]

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

Edit
Please can you provide some sharp picture of your main board which would be of help.

Is this better?

[JDC]

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

Those are only half of the pin outs. There are 18 of them in total. We need all of them plus the pin out name!
However... there is no voltage going to the Tcon. no voltage there, no pic. Maybe disconnect the tcon and see if the voltage re appears on the connector.

ON

-.009
12.13
12.13
-.01
24.48
-.011
3.51
3.51
3.104

OFF

0
.009
.009
0
.006
0
3.55
3.55
0

Attached is a diagram for the connection from the power board to the main board. It says:

P201

GND GND
12V N.C.
12V 12V
GND GND
24V 24V
GND GND
3.5V PD1M2
3.5V PD1M1
PWR-ON DRV-ON

[CapLeaker]

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

Using the main board pic I posted above as reference, from left to right:

ON

0
12.13
12.13
0
24.47
0
3.47
3.47
1.107

Off (but plugged in)

0
.007
.007
0
.004
0
3.55
3.55
0

F1 fuse on TCON:

ON .014 both sides
OFF 0 both sides

Those are only half of the pin outs. There are 18 of them in total. We need all of them plus the pin out name!
However... there is no voltage going to the Tcon. no voltage there, no pic. Maybe disconnect the tcon and see if the voltage re appears on the connector.

[Diah]

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

from yours T-CON photo it show to me the left ribbon cable not correct sitting at the panel socket., take them both out and check the Gold pins of them, then reset them correct, as they labeled with hand writing they seem had story.

[dick_barton]

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

You appear to have no TCON voltage, so no picture. You need to follow the wiring back to the mainboard and find the supply. Use your meter to trace the connection from the TCON fuse down to the mainboard. The TCON supply is probably supplied from a switched transistor or mosfet that I suspect has been blown.

Edit
Please can you provide some sharp picture of your main board which would be of help.

[JDC]

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

Hello,

I have had the exact thing happen to me on one of the first ones I've done LEDs on this model. Here is what happened to me. I take the tv down to the LEDs. Repair the LED strips as needed. I turn the tv on to check that all LEDs are working and rest the tv on the bottom edge. No I did not disconnect the tcon from the main board l, so when I tipped the tv up the ribbons to the panel touched the metal frame and shorted a component out on the main board. It was near the lvds connections smd square ic chip. So if you left the tcon plugged in and the ribbon cables in the tcon and tipped the tv up I would almost bet you shorted out the main board or something on the tcon from the ribbons touching the metal frame. If you took the ribbons off or unplugged the lvds cable then disregard my suggestion

I took the ribbons off the TCON when I was taking it apart but the connection from the TCON to the main board was left alone.

[JDC]

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

Umm... first off your pics are blurry.

Now there is a ribbon cable going from the PSU to the main board. There is a pin out on the PSU. Measure all those with the TV on and off and post the measured DC voltages with the corresponding pin out name.

Also try to turn on the TV and measure both sides of F1 on the Tcon against cold GND.

Report back.

Using the main board pic I posted above as reference, from left to right:

ON

0
12.13
12.13
0
24.47
0
3.47
3.47
1.107

Off (but plugged in)

0
.007
.007
0
.004
0
3.55
3.55
0

F1 fuse on TCON:

ON .014 both sides
OFF 0 both sides

[nicholas1110]

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

Hello,

I have had the exact thing happen to me on one of the first ones I've done LEDs on this model. Here is what happened to me. I take the tv down to the LEDs. Repair the LED strips as needed. I turn the tv on to check that all LEDs are working and rest the tv on the bottom edge. No I did not disconnect the tcon from the main board l, so when I tipped the tv up the ribbons to the panel touched the metal frame and shorted a component out on the main board. It was near the lvds connections smd square ic chip. So if you left the tcon plugged in and the ribbon cables in the tcon and tipped the tv up I would almost bet you shorted out the main board or something on the tcon from the ribbons touching the metal frame. If you took the ribbons off or unplugged the lvds cable then disregard my suggestion

[CapLeaker]

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

Umm... first off your pics are blurry.

Now there is a ribbon cable going from the PSU to the main board. There is a pin out on the PSU. Measure all those with the TV on and off and post the measured DC voltages with the corresponding pin out name.

Also try to turn on the TV and measure both sides of F1 on the Tcon against cold GND.

Report back.

[JDC]

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

Bump.

[JDC]

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

We need to see the pictures of the whole back side of the TV to see how all the boards are connected together, then we need the picture of the T-CON board.

Here you go. I took a closeup of the TCON fuses as well.

[ReeceyBurger123]

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

???

Didnt mean to comment on thread.

[JDC]

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

Delete.

???

[ReeceyBurger123]

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

Delete.