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Kevin123



Joined: 16 Jun 2017
Posts: 8
Location: United Kingdom

PostPosted: Fri Jun 16, 2017 3:58 am    Post subject: LG 42LN5400 - Dark Screen Reply with quote

The TV in question is a LG 42LN5400 which has a EAX64905301 Mainboard.

I originally thought it was the TCON board after reading various forums and watching videos but after finding a 2nd hand tested unit from a cracked Screen I still have the same issue.

- No capacitors look or feel like they have blown.
- You can see a dark image with a torch
- The TV still has sound


Test Results:

P201 - (18 Pin Connection to Logic board)
##### - Off / On
Pin 1 - 0.00v / 3.20v
Pin 3 - 3.39v / 3.42v
Pin 5 - 3.39v / 3.42v
Pin 7 - 0.00v / 0.00v
Pin 9 - 0.01v / 24.10v
Pin 11 - 0.00v / 0.00v
Pin 13 - 0.02v / 12.14v
Pin 15 - 0.02v / 12.14v
Pin 17 - 0.00v / 0.00v

Pin 2,4,6,8,10,12,14,16 & 18 unable to test due to my probes being too big.

-----

P802 (4 Pin Connection to LEDs)
###### - Off / On
Input - 107.4v / 216v-233v
37" - 43.2v / 142v-164v
39" - 43.2v / 148v-165v
42" - 0.08v / 0.73v

-----

Looking at P802 as the TV is a 42" I am guessing the low voltages are pointing to the main board being damaged rather then the LEDS?

UPDATED - Tested each SMD LED and 1 is blown.. Would this cause the entire lot not to illuminate?


Any help in aiding me with this would be great as I continue to learn.

Regards
Google

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JTS1957



Joined: 21 Jan 2009
Posts: 2286
Location: Far, Far Away

PostPosted: Fri Jun 16, 2017 8:08 am    Post subject: Reply with quote

norcal715 screen flash video shows step-by-step.

You can answer your own UPDATED question once you've installed NEW LED strips.

Do NOT forget to turn down backlight intensity.
Kevin123



Joined: 16 Jun 2017
Posts: 8
Location: United Kingdom

PostPosted: Mon Jun 19, 2017 3:27 am    Post subject: Reply with quote

The video shows me what I have already pretty much tested..

I just want to confirm the voltages on p802, as its a 42" TV and the range is only 0.08v off and 0.783v on rather then the 157.5 volts stated on the little key.. Would this mean the powerboard would need replacing?
JTS1957



Joined: 21 Jan 2009
Posts: 2286
Location: Far, Far Away

PostPosted: Mon Jun 19, 2017 12:19 pm    Post subject: Reply with quote

Kevin123 wrote:
The TV in question is a LG 42LN5400 which has a EAX64905301 Mainboard.


Le Interweb seems to say that that board is NOT the Mainboard, but the LED Driver/Power board.

Kevin123 wrote:
I just want to confirm the voltages on p802


Shop Jimmy photos of the EAX board show a P801? (P802 is a single pin next to LED socket.)
Kevin123



Joined: 16 Jun 2017
Posts: 8
Location: United Kingdom

PostPosted: Thu Jun 22, 2017 4:35 am    Post subject: Reply with quote

JTS1957 wrote:
Kevin123 wrote:
The TV in question is a LG 42LN5400 which has a EAX64905301 Mainboard.


Le Interweb seems to say that that board is NOT the Mainboard, but the LED Driver/Power board.

Kevin123 wrote:
I just want to confirm the voltages on p802


Shop Jimmy photos of the EAX board show a P801? (P802 is a single pin next to LED socket.)



For some reason I can never access shopjimmy, always says access denied...

This is a photo of the TV, from reading forums and watching videos the far left is the main board, far right logic board and the lower the Tcon.



and a close up of the board itself


The top readings are from the lower right connector in the image not sure why it rotated)

The lower readings are from the top left connector.

The EAX64905301 can be seen on the lower right
Google

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Kevin123



Joined: 16 Jun 2017
Posts: 8
Location: United Kingdom

PostPosted: Thu Jun 22, 2017 4:39 am    Post subject: Reply with quote

additional images..

P201 Connector (18 Pin)



P802 Connector ( 4 Pin)
JTS1957



Joined: 21 Jan 2009
Posts: 2286
Location: Far, Far Away

PostPosted: Thu Jun 22, 2017 9:08 am    Post subject: Reply with quote

Remember you are on one side of a large puddle, I am on the other.
That's why giving the FULL model number is important.

You got the tcon correct. Board on left is Power Supply/LED Driver and board on right is the Main (although logic is used occasionally).
The 'correct' part number for your PS/LED Drive board is 'EAY62810501.' Partial number is on bar code sticker.
Main board numbers?

You are seeing the silk screened 'P802' that refers to the single rivet-looking pin on the left of the LED connector. If you look to the right of the LED connector, you'll see the correct reference of 'P801.' Looking on the reverse (foil) side of the board will further confirm.

You need to read pin2 of P201. Either back-probe (from where the wires enter the connector) or 'tack-solder' a length of insulated wire to pin and measure at the other end.


Last edited by JTS1957 on Fri Jun 23, 2017 10:38 am; edited 1 time in total
Kevin123



Joined: 16 Jun 2017
Posts: 8
Location: United Kingdom

PostPosted: Fri Jun 23, 2017 4:31 am    Post subject: Reply with quote

Hi again JTS1957,

Thanks again for the helpful post.

To confirm the EAY62810501 number is that just the non European version as I cant see that printed on the board? (Can see the 62810501 part but not the EAY part)

I found this picture which I was using as a guide, can you confirm that pin 18 would be under pin 17 on this picture as that would be a ground?

[/img]
JTS1957



Joined: 21 Jan 2009
Posts: 2286
Location: Far, Far Away

PostPosted: Fri Jun 23, 2017 10:56 am    Post subject: Reply with quote

'EAY' is inferred.
http://imgur.com/rMPcgFZ
http://imgur.com/a/LNWQn

Brain fa*t - I corrected my earlier.
Kevin123



Joined: 16 Jun 2017
Posts: 8
Location: United Kingdom

PostPosted: Wed Jun 28, 2017 5:29 am    Post subject: Reply with quote

Sorry for the delay in my response..

I have tested pin 2 and the readings are as follows;

off = 0.04v
on = 2.97v
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