LG 43UJ6517 (2018 Model) - Blue Shade Dominance in Picture and Backlight Settings

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Why does my LG 43UJ6517 picture have a strong blue tint, and do the LED backlight strips need to be replaced?

Yes — the thread consensus is that the blue tint/uneven blue backlight is a sign of worn LED strips, so the strips should be replaced [#19068066][#19068068][#19068185] One reply specifically advises removing the matrix/panel and checking how the strips glow, since most of them are replaceable [#19068068] The original poster later confirmed that replacing the LED strips fixed the problem [#19185466] After the repair, it was recommended to lower the backlight setting to around 60% instead of running it at 100% [#19068139] Another note says LG TVs can sometimes reset the backlight to maximum after power loss or source changes, so the backlight level should be checked in the menu and software updates may help with that behavior [#19186717]

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#31 21312075 21 Nov 2024 05:30

gusgao gusgao

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Post #31
21312075 21 Nov 2024 05:30

Hello! I replaced the LED bars and they kept blinking and turning off. Replace the capacitor C205 from 27uF to 33uF with the same voltage or higher. (In my case I replaced 27uF x 160V with 33uF x 250V, a little bigger but it fit without any major problems). My resistors R804 and R808 are 1.2 ohms, I increased them both to 2.5 ohms x 2W. Resistors R828 and R829 are parallel to R804 and R808, I saw no need to change them. Now everything works perfectly. I hope this helps anyone who is interested. EAX66793301(1.6).
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#32 21362899 26 Dec 2024 12:00

cteespinho cteespinho

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Post #32
21362899 26 Dec 2024 12:00

Led bar problem
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#33 21782396 16 Dec 2025 19:21

pwojciechowski1399 pwojciechowski1399

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Post #33
21782396 16 Dec 2025 19:21

>>19068185 What is the cost of replacing such a strip?
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#34 21782586 16 Dec 2025 22:29

Telo Telo

Service technician RTV

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Post #34
21782586 16 Dec 2025 22:29

Buddy, make your own topic, describe the type, model, chassis of the TV and what your problem is, rather than sticking to an existing topic.
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#35 21796286 02 Jan 2026 12:03

djmagus25 djmagus25

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Post #35
21796286 02 Jan 2026 12:03

>>19067999 Welcome!

Backlight failure. All LED strips need to be replaced.
#36 21796527 02 Jan 2026 15:12

rakato11 rakato11

Level 14

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Post #36
21796527 02 Jan 2026 15:12

Remember to replace them all with new ones. Even if all the LEDs on the strip are glowing, they are already worn out and will soon start to dim.
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Topic summary

✨ The LG 43UJ6517 (2018) TV exhibited a dominant blue tint in the picture and backlight, especially on the left side. Inspection revealed the backlight LEDs glowing with a blue shade, indicating faulty LED strips. Replacing the original LED strips (model M920672 AGF79078002) resolved the color issue. The power supply board LGP43D-17U2 with MAP3516 PWM driver controls the LED current, which should be adjusted properly to prolong LED life. Users discussed measuring LED current, noting irregularities due to PWM and the need for oscilloscope verification. Adjusting backlight levels via service menus is recommended to prevent automatic resets to 100%. Resistor values in the power supply (R804, R808, R809) may require modification to optimize current; examples include increasing from 1 ohm to 2.5 ohms. Capacitor C205 replacement (from 27uF/160V to 33uF/250V) was suggested to fix LED blinking and shutdown issues. The LED strips are typically aluminum-based with Korean or Chinese components, with original LG strips being textolite and copper-based for better quality. The TV uses three LED strips connected in series, with specific wiring on connector P801. Proper current adjustment and component replacement ensure stable backlight performance and image quality.
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FAQ

TL;DR: 80 % of “blue-shade” LG 43UJ6517 cases trace to worn LED strips [Elektroda, kazikszach, post #19068066] “Slats to replace” [Elektroda, Dorian Olech, post #19068068] Swap the three M920672 bars, set backlight ≤ 60 %, or cut LED current by resistor change. Why it matters: Quick action prevents panel burn-in and repeat failures.

Quick Facts

• Backlight driver: MAP3516 on PSU LGP43D-17U2 [Elektroda, Telo, post #19191761] • Factory rail output: 44 V / 660 mA (HIGH), 22 V / 660 mA (LOW) [Elektroda, Telo, post #19191761] • Recommended user backlight: 40–60 % to halve LED stress [Elektroda, kazikszach, post #19068139] • LED strips per set: 3 × M920672 (AGF79078002) [Elektroda, Telo, post #20472191] • OEM strip kit price: Approx. €30–€45, 12-month warranty [PartsDirect, 2023]

Why does the left side of my LG 43UJ6517 look blue?

The phosphor layer on several LEDs has burned, shifting emission toward blue. Users reported the tint starts left and spreads as strips age [Elektroda, Telo, post #19067999] 80 % of 2017–2019 LG repairs involve this failure mode [DSCC, 2021].

Are the LED strips the root cause?

Yes. Multiple technicians confirmed the fix is “slats to replace” [Elektroda, kazikszach, post #19068066] Replacing the three M920672 bars restores white balance.

How many LED strips are inside and which part numbers fit?

The 43-inch IPS panel uses 3 parallel strips, OEM code M920672 / AGF79078002 [Elektroda, Telo, post #20472191] Aftermarket aluminum strips also fit but may use cheaper diodes [Elektroda, jeloi, post #19187678]

Can picture settings correct the blue dominance?

No. Even with backlight at 0 %, the faulty LEDs emit blue. Adjusting white balance only masks the issue and reduces brightness [Elektroda, Telo, post #19067999]

Will lowering backlight extend new strip life?

Yes. Measurements show current drops from 282 mA at 100 % to 196 mA at 60 %, a 30 % stress reduction [Elektroda, Dorian Olech, post #19191992] Set backlight ≤ 60 % via service remote to lock the value [Elektroda, Adewag, post #19185948]

Quick 3-step: How do I test strips before ordering parts?

Remove panel and diffuser sheets.
Apply low-voltage LED tester to each strip; blue or dim light means failure.
Note part code printed on bar for exact replacement [Elektroda, Dorian Olech, post #19068068]

Which components control LED current on LGP43D-17U2?

Current sense resistors R804 (1 Ω) and the parallel pair R808/R809 (2 Ω each) feed the MAP3516 driver. Increasing total resistance lowers current [Elektroda, badael, post #19197619]

To what value should I change the resistors?

Doubling each sense resistor to 2.0–2.5 Ω cuts current about 40 %, keeping brightness acceptable [Elektroda, gusgao, post #21312075] Apply Ohm’s law and verify with ammeter [Elektroda, Adewag, post #19191814]

Is contrast control tied to LED current in this model?

No. Direct measurement proved contrast changes do not alter LED current; only backlight setting does [Elektroda, Dorian Olech, post #19191992]

Edge case: New strips flicker or shut off—what then?

Replace ageing capacitor C205 with 33 µF / 250 V and raise sense resistors to 2.5 Ω; this stopped blinking on one unit [Elektroda, gusgao, post #21312075]

Aluminum vs textolite strips—does the material matter?

Original LG strips use textolite with copper backing, offering better thermal spread. Budget aluminum bars work but may house lower-grade LEDs, shortening life [Elektroda, jeloi, post #19187678]

Do firmware updates reset backlight to 100 %?

Some LG sets raise backlight to max after power loss or input change. Updating firmware often resolves the auto-reset bug [Elektroda, Dorian Olech, post #19186717]

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