Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Okay this saga has finally come to an end. I fiddled with the ribbon cables and the lines on the screen disappeared. That was all I needed to claim a victory and start putting it back together. Well I guess I manhandled it or maybe I wasn't gentle enough snapping the back case on. I turned the TV around to appreciate the fruits of my labor only to reveal a F!#king black spot where the screen had cracked in the corner.
I guess I'll be breaking it down and selling the parts.
Chillin014
Member
Last Activity: 10-29-2020, 09:01 AM
Joined: 06-14-2020
Location: Houston
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
A somewhat good update: I went ahead and replaced the MOSFET transistors (or whatever they are). This was unchartered territory for me and I ripped off part of the trace on one of them but I think I cobbled it back together alright. I did one at a time, and tested the TV after each. It wasn't until I replaced the second one that the flickering stopped and the TV began to function normally. I now have a steady backlight and a picture.
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My excitement...Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
I don't understand the question. The original resistor colors were Brown, Violet, Black, Silver, Brown. That's about all I know about them. The body color was that seafoam green color and they were at least twice the size of the new ones....Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Update : I replaced the resistors, no problem. All went smoothly in that regard. I plugged everything back in and the LEDs immediately began buzzing again. I decided to wait a moment longer and the LEDs continuously flashed on and off with a lot of buzzing. I actually think the buzzing might be one of the LED's arcing as I could see light shining through the holes in the back casing and in one particular area there was a more yellow colored light that seemed to flicker in sync with the buzzing.
...Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Well I sure appreciate the reassurance. After receiving my kit yesterday and seeing how tiny the transistors,etc are...I'm most likely going to put those on the back burner and hope for the best.
I have also confirmed the resistors I received, (which are also tiny compared to the ones I'm replacing), are 4.7Ohms resistors. I'm removing 1.7Ohms resistors. I will put my faith in the circuitboard gods and proceed.Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Totally agree. But I'm wondering why the backlight brightness couldn't just be turned down in the settings to accomplish the same thing?
I'm waiting on my repair kit to come in the mail but I got impatient last night and decided to take the risk and power on the TV with the new LED's installed. They lit up right away and then dimmed and I heard some buzzing and freaked out and and unplugged the TV. This was all within less than 1 second's time. I thought maybe I fried...Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Hahaha, and I really don't want to put that back cover on again until I know for sure this thing is fixed.
I've been watching some videos on YouTube but I really have no concept of what I'm replacing and why. I understand a resistor reduces the voltage to the LED's but going from a 1.7Ohms resistor to a 4.7Ohms resistor-is that okay? Is that safe or is it going to create a lot of heat?
And as far as the other components...I'd like to know if they are even...Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Hello all. It took me this long to get my replacement strips from China. I have installed them (and possibly damaged them during installation due to complications with the plastic retaining trim that holds the strips and aligns the large clear plastic panel).
Anyway, I'm still torn on what to do with the PS board. I feel comfortable replacing the resistors but not so much the other components in the shop jimmy kit :[ATTACH]221017[/ATTACH]
And if the resistors are...Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Thanks for the reply. SJ sells the kit but only has a video showing, and only makes mention of, replacement of the resistors. I'd like to test the transistors which would prove too risky for a novice to replace and see if I can "get away with" leaving them in place.
I lost my patience and disassembled the TV down to the LED strips, sure enough many of them were burnt. Some were essentially [I]charred[/I]. I went ahead and ordered new strips from China...Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Some photos of the board
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[ATTACH]218327[/ATTACH]Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Some photos of the board
[ATTACH]218326[/ATTACH]
[ATTACH]218327[/ATTACH]...Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Thanks for the info! Jeeze this sounds like a tough one. I'm a newbie in the sense that I've primarily only performed LED strip swaps/ board swaps. I've done other soldering but not on a circuit board before. I found IC9101 but I couldn't find the other transistors you mentioned. How can I test if these were damaged (while in circuit preferably)? I'm up for a challenge.
CNL802 is the connector/plug for the LED and I can't make sense of the listed voltages in the diagram....Leave a comment:
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Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
The screwless cover was a new one for me as well. Almost impossible to remove without cracking it in some way. I have once replaced some LEDS in an edge lit HISENSE and it was a pain but not impossible.
Anyway, I couldn't get any of the LED strips to power up using my tester at the harness but I'm not really sure I was making all the correct connections either.
I guess I should have posted the board # in the initial post if I expect any diagnostic help...Leave a comment:
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No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.
Hello all and thanks in advance for helping me with this.
I am a novice TV repair hobbyist and just picked up this Samsung UN65MU6290 / PS board # BN44-00873C with no backlight but otherwise seemingly fully functional. My initial assumption was the LED strips were bad but upon further research apparently the Power Supply board can also be at fault for "over driving" the LED strips. On ShopJimmy they are recommending to replace some resistors and other components (transistors?) in conjunction with the LED strips (although their referenced Youtube link only demonstrates replacing... -
Re: New Members - please post your introductions here
hello. Just a newbie getting into TV repair.Leave a comment:
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