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Old 07-30-2018, 09:24 PM   #21
mtskibum16
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Default Re: LG 55LW5600 No Video No Sound

Quote:
Originally Posted by budm View Post
Is it 12 Ohms readings in both directions of the probes?
When I just read it my meter showed 13.0 with the black probe on pin 1 and 13.6 with the black probe on pin 8.
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Old 07-30-2018, 09:47 PM   #22
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Default Re: LG 55LW5600 No Video No Sound

Black probe on pin 1, red probe on pin 8 = ?? Ohms.
Red probe on pin 1, black probe on pin 8 = ?? Ohms
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Old 07-30-2018, 09:52 PM   #23
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Default Re: LG 55LW5600 No Video No Sound

Quote:
Originally Posted by budm View Post
Black probe on pin 1, red probe on pin 8 = 13.0 Ohms.
Red probe on pin 1, black probe on pin 8 = 13.6 Ohms
Added the numbers in the quote.
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Old 07-30-2018, 10:07 PM   #24
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Default Re: LG 55LW5600 No Video No Sound

That is not normal to me, it should be in 100's or 1000's Ohms range.
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Old 07-30-2018, 10:15 PM   #25
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Default Re: LG 55LW5600 No Video No Sound

That's with the TV unplugged. It was higher when it was plugged in (but off).
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Old 07-30-2018, 10:24 PM   #26
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Default Re: LG 55LW5600 No Video No Sound

Is it safe to say the main board is the problem? I'd be willing to replace that (if I can find one) to get this back up and running.
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Old 07-31-2018, 12:51 AM   #27
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Default Re: LG 55LW5600 No Video No Sound

Being able to turn the TV on and off but with no picture, no sound, and no backlight is a very common issue we see from these TVs and it is caused by a bad main board. The BGA chip which is located underneath the large heatsing, is no communicating with the board properly. Generally performing a reflow or reball of this module will take care of your failure.
You most likely won't find a board for sale as these are discontinued and no longer in stock.
You will however find that a few different companies do offer mail in repair services on such modules. Be careful of eBay repair services however as you may notice all of them have no warranties on the repairs or only a 30-60 day warranty. Most eBay sellers with such short warranty periods are set up that way due to the fact that they do not perform a proper repair and usually repeat failures will occur within 6 months of the repair. If you do send in your module, make sure to find a service that offers an extended warranty such as a full 1 year warranty.
A link to a service listing is below:

http://www.nickstvs.com/store/p1425/EBT61398005

good luck
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Old 07-31-2018, 04:22 AM   #28
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Default Re: LG 55LW5600 No Video No Sound

Could you post a picture of IC505 and the area around it. As well focussed as possible.
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Old 07-31-2018, 04:31 AM   #29
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Default Re: LG 55LW5600 No Video No Sound

The AOZ1024D can supply an output current of 4 Amp continuous according to the data sheet. If the resistance at pin 8 is 13 ohms then at 3.3v out would be a current flowing of 253mA.
The AOZ1021 can provide a continuous output current of 3 Amps. I think the IC or the components around the IC is faulty.
Attached Files
File Type: pdf AOZ1024DI.pdf (1.03 MB, 13 views)
File Type: pdf AOZ1021.pdf (509.8 KB, 8 views)

Last edited by dick_barton; 07-31-2018 at 04:37 AM..
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Old 07-31-2018, 10:12 AM   #30
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Default Re: LG 55LW5600 No Video No Sound

Try to reflow or reball the main procecor in the mainboard.
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Old 07-31-2018, 02:04 PM   #31
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Default Re: LG 55LW5600 No Video No Sound

Quote:
Originally Posted by DIMITRIO View Post
Try to reflow or reball the main procecor in the mainboard.
As mentioned in the original post, I did the heatgun method and oven method to try and reflow the board initially with no success. What is the best method to do this? I followed advice from a few different sources I found around on the interwebz. Like for the oven - what temp and for how long? The heatgun really made me kind of nervous.
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Old 07-31-2018, 06:38 PM   #32
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Default Re: LG 55LW5600 No Video No Sound

Quote:
Originally Posted by dick_barton View Post
The AOZ1024D can supply an output current of 4 Amp continuous according to the data sheet. If the resistance at pin 8 is 13 ohms then at 3.3v out would be a current flowing of 253mA.
The AOZ1021 can provide a continuous output current of 3 Amps. I think the IC or the components around the IC is faulty.
I verified the number. It is correct. Both of those numbers are printed on the top of IC505 (one above the other). Z1024DI/ZA1012. I'll try and get a pic when my wife gets home. I don't think I have a camera that will get a very close and detailed pic.

Last edited by mtskibum16; 07-31-2018 at 06:50 PM..
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Old 07-31-2018, 10:34 PM   #33
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Default Re: LG 55LW5600 No Video No Sound

Quote:
Originally Posted by dick_barton View Post
Could you post a picture of IC505 and the area around it. As well focussed as possible.
This is the best I could do. Do you need more of the area or is that good? FYI pin1 looks more like pin 8 than the picture shows. I think that's mainly light pollution making pin 1 look blown out.
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File Type: jpg IMG_4085.jpg (351.2 KB, 23 views)

Last edited by mtskibum16; 07-31-2018 at 10:44 PM..
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Old 08-01-2018, 03:44 AM   #34
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Default Re: LG 55LW5600 No Video No Sound

Pin 7 & 8 connect to the coil. Does the other side of the coil connect to a ceramic capacitor?
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Old 08-01-2018, 05:24 PM   #35
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Default Re: LG 55LW5600 No Video No Sound

Quote:
Originally Posted by dick_barton View Post
Pin 7 & 8 connect to the coil. Does the other side of the coil connect to a ceramic capacitor?
Here's a pic.
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File Type: jpg IMG_4096.jpg (772.8 KB, 27 views)
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Old 08-01-2018, 10:02 PM   #36
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Default Re: LG 55LW5600 No Video No Sound

Might wanna check the power supply because I have seen them fail in these models. Check the secondary fuse, the mosfets and also inspect the blue ceramic capacitor near the mosfets.
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Old 08-02-2018, 03:47 AM   #37
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Default Re: LG 55LW5600 No Video No Sound

I think that IC505 is faulty. It creates the 3.3V_Normal supply from the 12V input to run so many other parts of the set as shown on page 104.

Last edited by dick_barton; 08-02-2018 at 03:52 AM..
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Old 09-18-2020, 12:48 PM   #38
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Default Re: LG 55LW5600 No Video No Sound

i have same tv...no picture using flashlight test

..i have no voltage at the fuse on the tcon

all voltages from ps seem good 3.3v 12v 24v
all voltages to leds seem good 56v and 56v

any ideas?
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Old 10-27-2020, 09:56 AM   #39
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Default Re: LG 55LW5600 No Video No Sound

Late to join this discussion, but my TV just failed. This case is almost identical in part to mine. I also measure ~13 ohms from 0.9_core rail to ground. I also measure the same ~12-13 ohms from 3.3V_norm rail to ground. Replaced IC505 no luck.
All connections between the two are through at least two resistors. Another common point is the main controller. Any other ideas? Thanks you
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Old 10-27-2020, 10:12 AM   #40
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Default Re: LG 55LW5600 No Video No Sound

55LW5600
seems to be common main board GPU issue
if you use a heat gun to heat up the GPU it may get tv to power on ok

i did it and it worked

obviously this may or may not be a perm fix

it is a main board issue and since the main board for this tv is so costly its not worth replacing
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