I have a LG 55UF6450-UA that when I turn it on it is just a white screen that does not show any menu or volume text on the screen and is unresponsive to remote commands except power on and power off. What are some things that I should test to try to narrow down the problem?
LG 55UF6450-UA with white screen
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Re: LG 55UF6450-UA with white screen
Also to clarify and update after further testing... It is a dim lit screen when I turn it on, not a bright white (1st picture). When I unplug one side of the T-Con it gets bright white on one side (2nd and 3rd pictures). Also I have been able to get volume coming out of the TV from an input. I think that this might mean a bad T-con? Is that correct?Comment
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Re: LG 55UF6450-UA with white screen
T-con on the bottom of the TV, you may have liquid damage to the panel, hope not.Comment
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Re: LG 55UF6450-UA with white screen
I would check voltages on t-con
T-con voltages (typical)
1. Vin (Vcc): 12Vdc or 5Vdc
2. (Vlogic,LCM, Vddd,VCC): 3.3Vdc
3. Vda (Vs, Vsource,VDD, Vdda,Avdd): 14Vdc~20Vdc
4. Vgh (Vgon,VGHR, Von, Vddg): 20Vdc~30Vdc
5. Vgl (Vgoff,VST,VGHF,VGHEVEN, Voff,Veeg): -5Vdc~-7Vdc
6. HVDD about 8v
7. DVDD,VDDC 3.3v, 1.2v
8. VCOM about 28vI assume no responsibility for any stupid suggestions I might post.Comment
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Re: LG 55UF6450-UA with white screen
Panel dis-assembly. People spray screen cleaner or children spill liquids and they drain down to the tab bonds and eventually eat away the copper tracks that attach to the LCD panel.
If a replacement T-con is cheap enough and the seller has a rather liberal return policy, I would try to replace the T-con before panel tear down.Comment
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Re: LG 55UF6450-UA with white screen
I would check voltages on t-con
T-con voltages (typical)
1. Vin (Vcc): 12Vdc or 5Vdc.
(13.22)
2. (Vlogic,LCM, Vddd,VCC): 3.3Vdc
(3.3)
3. Vda (Vs, Vsource,VDD, Vdda,Avdd): 14Vdc~20Vdc
(16.61)
4. Vgh (Vgon,VGHR, Von, Vddg): 20Vdc~30Vdc
(27.9)
5. Vgl (Vgoff,VST,VGHF,VGHEVEN, Voff,Veeg): -5Vdc~-7Vdc.
(Flashing between -7 & 27)
6. HVDD about 8v.
(8.09)
7. DVDD,VDDC 3.3v, 1.2v
(can't find...)
8. VCOM about 28vComment
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Re: LG 55UF6450-UA with white screen
in my notes, i have vcom listed as half of avdd approx.
perhaps someone can clarify this one.WHY CAN'T PHILIPS USE PHILLIPS HEAD SCREWS?Comment
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Re: LG 55UF6450-UA with white screen
Disconnect the lvds cable.
Connect a wire from 12v on the power supply and solder it to the TCON fuse.
Finally solder a small piece of wire to the vdc test point and connect it to pin 44 on the TCON input.
Turn on the tv.Comment
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Re: LG 55UF6450-UA with white screen
1) Is the lvds cable the input cable that comes into the topside of the TCON board?
2) I can't find a DC 12V+ source on the power board... Where should I be able to find this at?
3) Last, where is the VDC test point, n the TCON? I can't find it. Also I can't find a pin 44 on the TCON? Any help on location of these would be greatly appreciated.Comment
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Re: LG 55UF6450-UA with white screen
This may help: https://cdn.badcaps-static.com/pdfs/...d6ef3fc97d.pdfI assume no responsibility for any stupid suggestions I might post.Comment
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Re: LG 55UF6450-UA with white screen
This may help: https://cdn.badcaps-static.com/pdfs/...d6ef3fc97d.pdf
Does this mean bad Main Board?Comment
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Re: LG 55UF6450-UA with white screen
It certainly looks like it must be a main board problem. The above test eliminates any panel or Tcon fault since the pictures look good.Willing to help but I'm no expert.Comment
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