Just curious to know if anyone has ever repaired an LCD panel driver board. I believe I have a bad panel as I've replace everything else in the TV. TV has sound and back light but screen stays black. Tabbing on panel looks good too. I'm thinking possibly bad components on LCD panel driver board. Can't find schematics or even a general breakdown of how the driver board works. Does anyone know what usually goes bad on the panel driver board?
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Last edited by johniwad; 03-02-2018, 01:16 PM. -
Re: Has anyone ever repaired a bad panel driver?
Have you tried only one ribbon connection at a time between the tcon and LCD panel? This would mean pulling the ribbon from the right side only allowing the panel to be driven from the left side of the tcon.
Then reverse the process with the opposite side.
Also can you provide model number of tv?Last edited by freakaftr8; 03-02-2018, 01:32 PM.Did I leave the soldering iron on? -
Re: Has anyone ever repaired a bad panel driver?
I successfully repaired a Sony XBR55X850B the other day that had a shorted MLCC capacitor on the panel driver board. It had no picture on the shorted side, white screen with faint vertical lines on the other side.Did I leave the soldering iron on?Comment
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Re: Has anyone ever repaired a bad panel driver?
depending on the panel (which you have provided no info), lots of things can be done.... from removing the side tabs (one side), to testing / replacing capacitors on edge boards, to "pressure pads" to help with connectivity. So "fix" might be "workaround".Comment
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Re: Has anyone ever repaired a bad panel driver?
well then your first / next step would be to provide good information about the various voltages that are present as per the circuit board "printing" in and around any connectors / interconnection especially with respect to the power and main board and maybe tcon if it is different from the main boards.Comment
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Re: Has anyone ever repaired a bad panel driver?
https://www.youtube.com/watch?v=4v8DcqCNG4A
Powersupply testing, Heed the HIGH VOLTAGE WARNING CAN BE DEADLY, inverter boards can have 1000 volts and more, be careful with those too, if you work on any.Last edited by nomoresonys; 03-03-2018, 10:32 AM.Comment
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Re: Has anyone ever repaired a bad panel driver?
http://www.shopjimmy.com/samsung-bn9...-con-board.htm
Is that your T-CON board?
Did you verify that you have 12VDC at both ends of the SMD fues with ref to the chassis GND?Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: Has anyone ever repaired a bad panel driver?
Yes, a few. Most recent one was an LG 55LE5400. Had a single shorted MLCC on left driver. Had something with a bad LM1117 on the driver once too. Disconnect one ribbon cable at a time and power on(never hot swap), you should be able to get a half picture. If you've already tried that and got nothing, then it is probably before the drivers.Last edited by lookimback; 03-03-2018, 06:43 PM.------------signature starts here------------
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Re: Has anyone ever repaired a bad panel driver?
The Sony I worked on did not have a picture on either side but one side did represent a white screen with faint vertical lines. That side did not have the shorted capacitor. The side that did have the short capacitor would not show a picture at all. I guess or is always a slight possibility that both sides have a shorted capacitor Or there some interlinking between the 2 sidesDid I leave the soldering iron on?Comment
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Re: Has anyone ever repaired a bad panel driver?
Must have been some interlinking between the sides.------------signature starts here------------
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Re: Has anyone ever repaired a bad panel driver?
I should note that this model has exceptionally bad issued with BGA soldering under the main processor. Could be something to look at. Apply some heat around the board and see if situation changes.Did I leave the soldering iron on?Comment
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Re: Has anyone ever repaired a bad panel driver?
Notice that big heat sink and thought about that too. I may reflow or try a reball if I have the stencil. Funny thing is I bought a mainboard off ebay and had the same issue. I know the board I bought could be bad though.Last edited by johniwad; 03-04-2018, 10:35 AM.Comment
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Re: Has anyone ever repaired a bad panel driver?
Just try take a hair dryer and heat it up and see if the picture comes backDid I leave the soldering iron on?Comment
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Re: Has anyone ever repaired a bad panel driver?
Very rarely do I pay for any TV. I advertise to take away non workers. Generally I avoid broken screens as just too many different models of tv . This week I have a friend bringing me 5 TVs for nought and asking if I have anything over 45" to sell as he has a buyer for me. In another two months a council cleanup occurs - last year I advertised just before that to "keep them out of the compactor" and finished up with 20.Comment
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Re: Has anyone ever repaired a bad panel driver?
I'm really leaning toward a bad panel. I have tested with two different main boards and two different t-con boards and have the same results. I will upload pics of the panel driver boards if anyone want chime in on where possible problems could be.Comment
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Re: Has anyone ever repaired a bad panel driver?
as suggested earlier, list and check the voltages of the various pins / connectors that are listed / printed on the boards (either main and power and tcon). This will provide the forum with some understanding of what's happening with the set electronically.Comment
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Hello, this is my first post and im just a beginner, so be easy on me guy. thanks
i have a LED chandeilier that switches colors from white to cool white to warm when toggling the switch, it has 24 LED arms, each arm is 30 CM length.
i have no datasheet at all for the LED lights, all i have is its length.
long story short, testing the chandelier on the ground, and it works fine for 1 - 2 - 6 hours, no problem.
as soon as i fix the chandelier to the ceiling and bury the driver inside the hub,... -
49UJ6500 LCD panel has a lighter band on top when first powered on. Goes away (or gets much fainter) after TV on for a few min. After powered off for awhile and power back on, same band appears. If powered on immediately after powering off, no or much fainter band. Running the latest firmware.
Disassembled the TV and lifted the LCD panel during testing. Band is on the LCD panel (can see the band on the panel as I lift it slightly) Backlight is perfectly even at the top edge. Double checked LCD panel alignment in the frame and is perfect but since band moved with the panel, its on... -
TV flashes backlight then reboots over and over. no image. Client said it used to have image for a bit before rebooting. Got worse over time.
tcon is built into mainboard.
Only one cable goes to panel boards.
there is a cable from one panel board to the other that links them.
cost cutting measure that results in us having harder time to diagnose.
removing the link to the second panel board allows TV to stay on with stable backlight but no image.
used cut off tape method to mask 1 maybe 2 pins on the side of the cable that goes to that second panel board.... -
I had a the above tv qn55q60r that had a bad panel but everything else good. I had another panel here from un55nu6900 with bad leds and melted diffusers.
I put the nu6900 panel in and powered it up and it does work but there are lines vertical lines.
I was trying to change the panel type in the service menu but don’t see my exact panel. Anyway to fix this or someone have similar experience.
the clear picture is the panel type from the service menus on the nu6900. The other 1 is the panel type that was set for the q60r with the bad panel....01-13-2024, 01:57 PM -
I have a TCL 55P6US with sound and backlight but no picture. This model does not have a T-CON board, and the right (rear perspective) panel board is fed from the left panel board. I have not been able to induce any change by disconnecting the secondary panel board or the tape cut-off method on the primary board.
There are a bunch of voltages missing on the panel boards. I can't find any shorted caps of the panel boards, and all of the missing voltage rails read in the kiloohms, which leads me to suspect the issue may lie on the circuit board, rather than a short in the panel.
...
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