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Old 02-02-2021, 12:04 PM   #21
Diah
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Default Re: Does anyone know what LEDs an LG 55LN5400 uses?

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Originally Posted by Daveleone View Post
Unfortunately, I've already taken things apart again. Do I need to test the voltage with the TV on?
forget it if you taken them out from the tv. led tester reading are always different from power boards fixed currents.
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Old 02-02-2021, 12:09 PM   #22
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Default Re: Does anyone know what LEDs an LG 55LN5400 uses?

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Originally Posted by Diah View Post
forget it if you taken them out from the tv. led tester reading are always different from power boards fixed currents.
Ok, I haven't taken them out of the TV yet, but I did take the panel apart again. I'll try powering it on later and taking the readings directly.
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Old 02-02-2021, 04:35 PM   #23
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Default Re: Does anyone know what LEDs an LG 55LN5400 uses?

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Ok, I haven't taken them out of the TV yet, but I did take the panel apart again. I'll try powering it on later and taking the readings directly.
then u can turn on with out lcd and read them direct on powerboards socket
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Old 02-02-2021, 07:00 PM   #24
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Default Re: Does anyone know what LEDs an LG 55LN5400 uses?

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then u can turn on with out lcd and read them direct on powerboards socket
3 full A-B strips (36 old LEDs): 78.9v = 2.1917v per LED (~2.2v per LED)
4 full A-B strips (42 old LEDs + 6 new LEDs): 110.0v
So, 6 new LEDs = 110v - (42*2.1917v) = 17.95v = ~3v per LED

Last edited by Daveleone; 02-02-2021 at 07:02 PM..
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Old 02-03-2021, 02:26 AM   #25
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Default Re: Does anyone know what LEDs an LG 55LN5400 uses?

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Originally Posted by Daveleone View Post
3 full A-B strips (36 old LEDs): 78.9v = 2.1917v per LED (~2.2v per LED)
4 full A-B strips (42 old LEDs + 6 new LEDs): 110.0v
So, 6 new LEDs = 110v - (42*2.1917v) = 17.95v = ~3v per LED
are you sure from the wiring.. it make no sense to me if the power boards had 2 channel LED per yours wiring 36 LED + 48LED, at least it should 42 LED each.

can you show clear photo on yours powerboards at the LED Sockets from both side please.
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Old 02-03-2021, 10:15 AM   #26
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Default Re: Does anyone know what LEDs an LG 55LN5400 uses?

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can you show clear photo on yours powerboards at the LED Sockets from both side please.
The wiring goes from end to end of the LED strips up the chain (in series) with a terminator at the end of each of the 2 the chains. 1 chain is 4 A-B strips, the other chain is 3 A-B strips.

The blue/white pair of wires powers the 3 strip chain, while the blue/black pair of wires powers the 4 strip chain.
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File Type: jpg 20210203_091848[1].jpg (547.2 KB, 7 views)

Last edited by Daveleone; 02-03-2021 at 10:21 AM..
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Old 02-03-2021, 11:25 PM   #27
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Default Re: Does anyone know what LEDs an LG 55LM5400 uses?

You LCD panel does not use the same amount of LED for each LED string, if you look at the Voltage chart and the Voltage rating of the filter caps for the two boost converter circuits you will see the two LED drive Voltages for the Low LED string and High LED string, thus different LED drive Voltages.
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Old 02-11-2021, 04:29 PM   #28
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Default Re: Does anyone know what LEDs an LG 55LM5400 uses?

Just to close this thread out, I got the replacement original LED strip and everything works great. No hot spots. Case closed.
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Old 02-11-2021, 04:49 PM   #29
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Default Re: Does anyone know what LEDs an LG 55LM5400 uses?

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Just to close this thread out, I got the replacement original LED strip and everything works great. No hot spots. Case closed.
Thanks for the follow-up.
So where did you get the correct replacement strips from so in the future people will know where to get them?
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Old 02-11-2021, 05:38 PM   #30
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Default Re: Does anyone know what LEDs an LG 55LM5400 uses?

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Thanks for the follow-up.
So where did you get the correct replacement strips from so in the future people will know where to get them?
I ended up buying the exact replacement strip for mine, by part number (LZ5501LGEPWA-DL84-R-REV.0) off of eBay, instead of using the "updated" POLA2.0 parts. Found a guy selling the A-side strips for $21.99 or best offer w/free shipping. I offered him $10 for one and he accepted.
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Old 02-11-2021, 06:01 PM   #31
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Default Re: Does anyone know what LEDs an LG 55LM5400 uses?

Let me ask a stupid question but why can you not use the original diffuser that were on the led strips and see how that would work on the replacement led strips

I realize that this might be some work but would be justifiable to do that
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Old 02-11-2021, 06:15 PM   #32
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Default Re: Does anyone know what LEDs an LG 55LM5400 uses?

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Let me ask a stupid question but why can you not use the original diffuser that were on the led strips and see how that would work on the replacement led strips

I realize that this might be some work but would be justifiable to do that
Actually, I did try that with one strip (see post #17 and #18). It didn't work because the LEDs themselves that are used in POLA2.0 are brighter (Diah explained this in post #16) and still created a hot spot even with the wider diffusion pattern. The 55LN5400 just doesn't have adequate diffusion layers to diffuse the brighter LEDs used in POLA2.0.

Last edited by Daveleone; 02-11-2021 at 06:16 PM..
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Old 02-11-2021, 08:17 PM   #33
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Default Re: Does anyone know what LEDs an LG 55LM5400 uses?

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Actually, I did try that with one strip (see post #17 and #18). It didn't work because the LEDs themselves that are used in POLA2.0 are brighter (Diah explained this in post #16) and still created a hot spot even with the wider diffusion pattern. The 55LN5400 just doesn't have adequate diffusion layers to diffuse the brighter LEDs used in POLA2.0.
I must have missed this part sorry about that
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