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Boot Loop, Please help, works if ribbon cable is disconnected?

QN70Q6DTAFXZA https://youtu.be/JswMuvDtIR4 - video of it boot looping.

So, the main board and power board and cables are good (replaced them all), screen gets power and lights up full with no issues, however it goes into a boot loop when everything is connected. WHEN I disconnect only the ribbon cable (which is new) the TV boots full, the sound lets me know it is in the operating menu and clicking around dings and selects things properly. Obviously because the ribbon is disconnected the screen (which is on and backlit fine) just has no picture. So the only thing left is this long thin (about 1 in) strip of computer board that runs along the entire bottom of the back that the ribbon cable is plugged into and has connectors that wrap to the front LEDs (I also replaced the metal Y connectors that go to this long stripy board thingy). I cant find this long thin stripy board part anywhere. Please let me know if this is fixable, and how to find this part if that is the answer. Thanks so much, mahalo. - Mike

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@firepaint those boards are the LCD driver boards and are considered part of the panel. They are not replaceable since the ribbon cables from those to the LCD are bonded by a special process to the panel. It would be unusual for those to be the cause of a boot-loop, but anything is of course possible. Post a short video about what you refer to as a boot-loop. It sounds like yiu are saying that it works without the display connected but not with it connected. That would mean your panel has failed.

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Thank you. Yes it works when the ribbon cable is disconnected (the ribbon goes from the main board to the panel. However the LED lights up bright white seen from the back, just no picture comes through because the ribbon is disconnected. When the ribbon is connected it enters a 15 second boot loop with no picture on front, where the LED tries to start but gets overridden and shuts down (unlike when the ribbon is disconnected it stays on), I tried to upload a video but the site would not accept it.

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@firepaint that means your backlight turns on but you still do not get a video signal to the LCD. The backlight is independent of the video circuitry. The only thing left is the panel.

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I had this issue too, there are chips embedded in the ribbon cable connected to the LCD panel. I think this is one of the most dumb things Samsung as done, but they obviously don't care about repairability anyway. Here's what I followed: https://youtu.be/atNmhu7HMj0 The going theory is that the chips in the lcd connector communicate with the main control board and tell it to shut off if the chip indicates that there's some kind of fault. If you put tape in the ribbon connector can you can block these signals and makes most of the TV work! I just fixed mine today but I'm having some problems with lines on the tv alongside some colour issues.

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@James Arnott "problems with lines on the tv alongside some colour issues" is casued by blocking those signals needed. You are right about the CoF but it's not just Samsung. It's all of them. Pretty much unrepairable for the DIY'er for now. There may be things coming our way soon.

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Having the exact same issue with my QN65...Two years old..ugh

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When the panel is toast the game is over. Can't replace panels in todays market!

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Right, but what if it is the driver board. Measure the components and voltages on those.

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The driver boards and ribbon cables are permanently attached to the led panel and can't be repaired

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@reakers components remain replaceable even on the driver boards. I'd still be checking VGH VGL etc. depending on whats going on. Even a Gamma IC could be replaced.

But you are right, the normal DIY'er can't replace those board (yet)

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I have the same issue with a Samsung un65nu8500. I can disconnect any one of the 4 connectors and it boots without issues, just no display. As each of the 4 cards are attached to the led screen with 3 ribbon cables I do not understand how disconnecting any of them does what it does but to be honest I do not know much about the led sheet itself.

It sounds like the only fix is to replace the led screen itself. The replacements I have seen are running around $900

Any other ideas out there or just salvage the boards and sell them on ebay?

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@tinkan try a tape -off on the side that has failed. success rate for that is somewhere in the 70-80 % but it may give you a few more "miles" on your TV.

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Mike J zal eeuwig dankbaar zijn.
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