LG 42cs570 shuts off after 10 seconds of powering on.


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LG 42cs570 shuts off after 10 seconds of powering on.

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davisflow
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Oct 6, 2015, 10:47 PM

Post #1 of 49 (5424 views)
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LG 42cs570 shuts off after 10 seconds of powering on.	Can't Post

Hi all, I have a LG 42cs570, I purchased it in 2012. Now, when I turn it on it flashes to a black screen 3 times, and then turns off after about 8-10 seconds; during this time, (between the black screens), video and audio are playing normally; this happens every time I try to turn it on. I have removed the back cover, and there is nothing obviously wrong with the boards or capacitors. I have also removed all remotes from the room, unplugged it, waited about 10 minutes and plugged it back in. It is plugged directly into an outlet that other devices are able to use without problems.
It is only 3 years old! Unsure

I would like to repair this myself, and I have a voltmeter, Any advice for me!?

jts1957
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Oct 6, 2015, 11:46 PM

Post #2 of 49 (5419 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Board numbers? Or Service literature?

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Location: Far, Far Away

davisflow
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Oct 7, 2015, 12:16 AM

Post #3 of 49 (5416 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

You are asking for the board numbers?
Power board eay62770801
Main board eax64290501 (0)
T-Con board 6870c-0309d

Or are you asking me if I need the #?

What I am looking for is some direction in what to replace, is there a way to identify which component is faulty, without just swapping them all out for new boards? I have a voltmeter, that I can borrow, but I have no idea how to begin testing the components.
I want to fix it, but I don't want to just buy one of the boards at random, and have wasted money on this...

jts1957
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Oct 7, 2015, 1:02 AM

Post #4 of 49 (5413 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Power Supply / Inverter (IP) board Connector P201 Voltages at Plug in. (TV in Standby)

I do NOT have your set in front of me. Nor do I have its service literature. I have hidef pictures on a website. Many manufacturers may use more than a single part number power supply or main board during the production run. Just trying to get on same page.

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Location: Far, Far Away

(This post was edited by jts1957 on Oct 7, 2015, 1:06 AM)

davisflow
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Oct 7, 2015, 3:43 AM

Post #5 of 49 (5407 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Thanks for the replies.
I called LG and asked about the power supply board, they gave me this part number, EAY62770801. On http://www.shopjimmy.com/lg-eay62770801-power-supply-backlight-inverter.htm the part appears identical the power supply in the TV; and they call it LG EAY62770801 (LGP42-10LF) Power Supply / Backlight Inverter.

Am I answering your question?

jts1957
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Oct 7, 2015, 4:23 AM

Post #6 of 49 (5404 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

You appear to be a question behind:
1) Are all standby power supply voltages present at P201 connector on IP (Inverter/Power Supply) while set is IN STANDBY?

SJ IS the hidef picture site.

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Location: Far, Far Away

(This post was edited by jts1957 on Oct 7, 2015, 4:24 AM)

davisflow
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Oct 7, 2015, 8:21 AM

Post #7 of 49 (5394 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

got it, will test and reply tomorrow afternoon.

davisflow
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Oct 8, 2015, 1:20 AM

Post #8 of 49 (5380 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

I have tested P201; both with the cable plugged in, (which supplies the main board), and with the cable unplugged.
With the cable plugged in, the "red power off light" on the front of the TV is on. With the cable unplugged, the light is off, and I am unable to get it to turn on by shorting the power on and adjacent 20v pin.
Whether the cable is plugged in or not, the only pins that have power are the four 3.5v pins, they register as 3.417. The other pins all read as 0.

davisflow
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Oct 8, 2015, 1:55 AM

Post #9 of 49 (5377 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Does this indicate that the power supply board is the problem?

jts1957
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Oct 8, 2015, 2:32 AM

Post #10 of 49 (5373 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

ALL CONNECTORS PLUGGED IN NORMALLY UNLESS DIRECTED OTHERWISE!
Would YOU try to jump start an automobile with 68.52 Volts? IF 20 Volts is/was present you're likely to fry your Main Board.

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1) Are all standby power supply voltages present at P201 connector on IP (Inverter/Power Supply) while set is IN STANDBY?

ONLY 3.5V
IN STANDBY equals set plugged into mains, but Power button NOT yet pressed.
Well since you're jumpin' ahead again: How about present Even AFTER set turns off 'after about 8-10 seconds'?

2) Are any run voltages present (12 Volts or 20 Volts WHEN SET IS BROUGHT OUT OF STANDBY? ('Brought out of Standby' equals POWER button on TV or Remote pressed and released ONCE.) We know you'll want to jump ahead again, so ... How about present Even AFTER set turns off 'after about 8-10 seconds'?

-------------------------
Location: Far, Far Away

davisflow
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Oct 8, 2015, 3:01 AM

Post #11 of 49 (5371 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

"ALL CONNECTORS PLUGGED IN NORMALLY UNLESS DIRECTED OTHERWISE!"
Ok, gotcha. Just first time doing this. Will try to follow directions better Smile

Want to make sure we are on the same page here.
When you say "set plugged into mains" you mean the TV is plugged into the outlet, correct?

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2) Are any run voltages present (12 Volts or 20 Volts WHEN SET IS BROUGHT OUT OF STANDBY? ('Brought out of Standby' equals POWER button on TV or Remote pressed and released ONCE.)

Yes, all of the 12 and 20 volts are present when the set is brought out of standby; (and are present continuously for the 8-10 seconds the set is on, and is flashing between the black screen and the main screen.)

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We know you'll want to jump ahead again, so ... How about present Even AFTER set turns off 'after about 8-10 seconds'?

After the set turns off, the voltage at the 12 and 20 volt pins is not present (only 0.003.)

jts1957
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Oct 8, 2015, 3:33 AM

Post #12 of 49 (5363 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Mains / AC / Receptacle / outlet switch strip (when ON) = All same

Just to clarify: 3.5 Volts Stand by ... How about present Even AFTER set turns off 'after about 8-10 seconds'?

3) Are control voltages present (POWER ON or INV ON/OFF) AND AT what level ... a) while in stand by? b) when set is brought out of stand by? c) How about present Even AFTER set turns off 'after about 8-10 seconds'?

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Oct 8, 2015, 3:35 AM)

davisflow
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Oct 8, 2015, 3:58 AM

Post #13 of 49 (5360 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

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Mains / AC / Receptacle / outlet switch strip (when ON) = All same

Ok, good to know.

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Just to clarify: 3.5 Volts Stand by ... How about present Even AFTER set turns off 'after about 8-10 seconds'?

Yes, they are present at all times the set is plugged into the outlet.

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3) Are control voltages present (POWER ON or INV ON/OFF) AND AT what level ... a) while in stand by? b) when set is brought out of stand by? c) How about present Even AFTER set turns off 'after about 8-10 seconds'?

"POWER ON":
a) While in standby: Not present.
b) When the set is brought out of standby: yes, 3.25 continuously until set switches off.
c) After the set turns off: not present.

INV ON/OFF:
a) While in standby: Not present.
b) When the set is brought out of standby: Yes, 2.9V; BUT, when the screen flashes on, the reading briefly jumps to 0 and back to 2.9.
c) after the set turns off: Not present.

jts1957
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Oct 8, 2015, 4:10 AM

Post #14 of 49 (5358 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

And during those same three periods what are A-DIM ... D-DIM and ERROR doing?

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Location: Far, Far Away

davisflow
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Oct 8, 2015, 4:31 AM

Post #15 of 49 (5355 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

ERROR:
a) While in standby: Not present.
b) When the set is brought out of standby: Yes, present; 3.4 when screen flashes off and 0.028 when screen flashes on
c) After the set turns off: not present.

P-DIM:
a) While in standby: Not present.
b) When the set is brought out of standby: Yes, present; 3.1, but briefly drops down to zero when screen flashes on.
c) After the set turns off: not present.

A-DIM
a) While in standby: Not present.
b) When the set is brought out of standby: Yes, present; 3.1 when screen flashes on, 1.7 when screen flashes off.
c) After the set turns off: not present.

jts1957
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Oct 8, 2015, 4:47 AM

Post #16 of 49 (5349 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

The first 2 sound like the screen is lit coming out of stand by. I would think all three would start screen off .. then on .. then off again.

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Location: Far, Far Away

davisflow
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Oct 8, 2015, 5:00 AM

Post #17 of 49 (5346 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Hmm. Well, when I press the power button, here is the sequence: Screen on, then off, then on, then off, then on, then off, then on, then off.
So 4 total episodes of the screen flashing on.

I have a video of it, playing content and flashing on and off, and can upload it or email it if this is helpful.

jts1957
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Oct 8, 2015, 5:39 PM

Post #18 of 49 (5318 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Ignore that for now, I guess?

Next make a jumper that you can connect from POWER-ON to any of the 3.5V pins. This is only for a test, you shouldn't let stay running more than a minute or so at a time. If you can verify that 12V and/or 20V are coming up while you do this, all the better. Of course pinpoint source of any flame or smoke that occurs while doing test.

If power supply/inverter passes this test, make a second jumper that you can connect from INV ON-OFF to any of the 3.5V pins. Again, even if back lights come up and stay lit, do not run for more than a minute. If they shut down monitor ERROR pin, to see if it follows on/off of the bulbs. One value when bulbs are lit versus a second value when bulbs are extinguished.

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Location: Far, Far Away

davisflow
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Oct 9, 2015, 12:25 AM

Post #19 of 49 (5312 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

ok, this would be with the connector unplugged right?

I will have to go by radioshack, or something, I can't think of anything that I have around the house that would work for this test.
I work the next two nights, so I wont have time to try this until Saturday, 10/10, in the afternoon; unless you can recommend some common household item that might work for this test?

jts1957
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Oct 9, 2015, 2:19 AM

Post #20 of 49 (5307 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Try it both ways if you like. Connected first. Either way YOU are trying to take over a couple of Main board functions. If Power Supply / Inverter responds correctly to commands that YOU are providing, then it can be eliminated as cause.
There should be some play around where their wire enters molded connector housing (I presume this was where you were back-probing to get voltage readings). Any wire of a particular diameter and length should be able to wedge between housing and metal crimp connections. Old resistors wire leads come to mind. Quarter and half watt are fairly thin diameter, One, two and 3 watt getting progressively larger in diameter. A piece of solder itself may work.
You could also remove board, tack solder an insulated wire to the appropriate connector pins on the foil side of board and reinstall board.

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Location: Far, Far Away

(This post was edited by jts1957 on Oct 9, 2015, 2:24 AM)

davisflow
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Oct 10, 2015, 11:07 PM

Post #21 of 49 (5280 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

(I was able to connect the pins with the connector unplugged, but not with the connector plugged in.)
The below tests are with the connecter Unplugged.

Quote

Next make a jumper that you can connect from POWER-ON to any of the 3.5V pins. This is only for a test, you shouldn't let stay running more than a minute or so at a time. If you can verify that 12V and/or 20V are coming up while you do this, all the better.

The red power light did not illuminate, however, 12V pin had 12V; and 20V pin had 18.5V.

Quote

If power supply/inverter passes this test, make a second jumper that you can connect from INV ON-OFF to any of the 3.5V pins. Again, even if back lights come up and stay lit, do not run for more than a minute. If they shut down monitor ERROR pin, to see if it follows on/off of the bulbs. One value when bulbs are lit versus a second value when bulbs are extinguished.

When I plugged the set into the outlet, the back light comes on for about 1 second, during which time the error pin reads 0.02V, Then the back light shuts off and the error pin reads 3.5V. The red power light is not lit during this time.

So the Power Supply / Inverter passed the tests then?

jts1957
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Oct 11, 2015, 2:32 AM

Post #22 of 49 (5262 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

No power to the Main board = No red power light (or anything else for that matter).
You having sound/pix between dark screens, It trying to turn IP power On-Off & Inverter On-Off ... I think we can safely eliminate Main as the cause.

Power / Inverter
Power supply portion IS Good - Can only say at this point, (without researching Error - which I assume comes from back light control IC on foil side on board and I can't make out either the location number next to it or part number on the IC itself) that either one or more bulbs are defective and error is properly shutting down the set or a part (open transformer winding, shorted or open driver device, etc.) in the Inverter circuit is defective.

IF a bad bulb is the cause, replacing IP board will have no effect.
Visualizing the bulb array (especially bulb ends) would confirm or deny, but there is no easy way to do so without taking the panel (at least partially) apart, which can be dangerous for the unskilled.

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Location: Far, Far Away

(This post was edited by jts1957 on Oct 11, 2015, 2:47 AM)

davisflow
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Oct 11, 2015, 6:53 AM

Post #23 of 49 (5255 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

Hmm, well, then it sounds like I won't be attempting to visualize the bulb array. Are you able to place a rough percentage on the bulb array as the culprit vs the Power/inverter board? Where would you place your bet?

It looks like it would cost me about $70 to buy the Power Supply / Backlight Inverter board btw, and atm.

jts1957
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Oct 11, 2015, 11:46 AM

Post #24 of 49 (5250 views)
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Re: [davisflow] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

With back light control IC number, a way to bypass shutdown may possibly be obtained.

You don't notice any horizontal areas of screen that are dimmer than rest of screen? A steady non-changing picture or a 'blue screen' would be easiest to observe.

-------------------------
Location: Far, Far Away

davisflow
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Oct 12, 2015, 12:47 AM

Post #25 of 49 (5246 views)
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Re: [jts1957] LG 42cs570 shuts off after 10 seconds of powering on. [In reply to]	Can't Post

You said

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back light control IC on foil side on board and I can't make out either the location number next to it or part number on the IC itself)

I can take a look at the board for the number, but not sure what I am looking for...Where would this number be?

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You don't notice any horizontal areas of screen that are dimmer than rest of screen? A steady non-changing picture or a 'blue screen' would be easiest to observe.

No I didn't, but the picture is only up for a second or two before it shuts off, so I can't really carefully examine the screen.

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