Hi everyone!
Hope you're all having a great day, and thank you very much for stopping by and taking the time to read this post to help me with my parents' Samsung TV.
My issue: No backlight.
Model: QE82Q70RAT
Type No: QE82Q70RAT
The TV was already serviced by Samsung once under warranty for the exact same issue, but six months after the fix, the backlight went out again. Now, Samsung is asking for nearly the same price as a brand new TV to fix this with the same 6-month guarantee.
So hopefully, I can fix this cheaper.
I figured out that unplugging the power board from the LED driver board occasionally made the backlight work again.
My initial thought was that the driver was bad, so I found a cheap replacement, but that didn't fix it.
Maybe the power board is bad, but I believe I've checked all the Vdry and A13V output, and they seem to be fine, so I'm kinda lost.
The PSU board is: BN44-00983B
The LED driver board is: BN44-00991A
The main board is: BN94-13999B
If someone can tell me what to look for or measure, I have all the tools needed for the job. I'm just clueless about what to check.
I've noticed a pin named BLU_ON/OFF on the LED driver board, and it's at 5V when the TV is on.
There is a FAULT pin coming from the PSU board, and it's at 5V. I don't know if it's an active low pin; also, I can't see any visual damages.
On the PSU board, I've tested some dual common cathode Schottky diodes in a TO-220F-3L package; they seem to be fine. STB/ON is at 12.8V instead of 12.35V, Vdry is at 84.7V instead of 84V, and Vamp is at 17.8V instead of 17.1V. I don't think those discrepancies are significant.
If you need something else (high-resolution pictures, measurements, scope traces), just tell me what to do.
Again, thanks to all for considering helping me.
Hope you're all having a great day, and thank you very much for stopping by and taking the time to read this post to help me with my parents' Samsung TV.
My issue: No backlight.
Model: QE82Q70RAT
Type No: QE82Q70RAT
The TV was already serviced by Samsung once under warranty for the exact same issue, but six months after the fix, the backlight went out again. Now, Samsung is asking for nearly the same price as a brand new TV to fix this with the same 6-month guarantee.
So hopefully, I can fix this cheaper.
I figured out that unplugging the power board from the LED driver board occasionally made the backlight work again.
My initial thought was that the driver was bad, so I found a cheap replacement, but that didn't fix it.
Maybe the power board is bad, but I believe I've checked all the Vdry and A13V output, and they seem to be fine, so I'm kinda lost.
The PSU board is: BN44-00983B
The LED driver board is: BN44-00991A
The main board is: BN94-13999B
If someone can tell me what to look for or measure, I have all the tools needed for the job. I'm just clueless about what to check.
I've noticed a pin named BLU_ON/OFF on the LED driver board, and it's at 5V when the TV is on.
There is a FAULT pin coming from the PSU board, and it's at 5V. I don't know if it's an active low pin; also, I can't see any visual damages.
On the PSU board, I've tested some dual common cathode Schottky diodes in a TO-220F-3L package; they seem to be fine. STB/ON is at 12.8V instead of 12.35V, Vdry is at 84.7V instead of 84V, and Vamp is at 17.8V instead of 17.1V. I don't think those discrepancies are significant.
If you need something else (high-resolution pictures, measurements, scope traces), just tell me what to do.
Again, thanks to all for considering helping me.
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