No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

[diif]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Thanks, but Shop Jimmy is not willing to provide the part numbers. I think the IC part number may be SEM4082A.

Yes it is https://www.ebay.com/itm/160633490803

[BiondicTV]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Thanks, but Shop Jimmy is not willing to provide the part numbers. I think the IC part number may be SEM4082A.

[nomoresonys]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

I'm not seeing part numbers of the kit, if there's no markings on the IC, transistors, so you can look up the datasheets, I guess just email shop jimmy and ask them since the kit is out of stock, can they tell you which IC and transistors you need to get, the resistors are 4.7 ohms, theyre out of stock kit is there: https://www.shopjimmy.com/samsung-bn...nt-repair-kit/

[BiondicTV]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

I'm looking for the IC9101, the two switching transistors, Q9101C and Q6201C part numbers. Shop Jimmy doesn't have the repair kit in stock. Your help is appreciated.

The model number of the TV is UN65MU6290VXZA. Thank you.

[nomoresonys]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

they don't seem to be including IC9101 in the kits that I'm seeing, maybe test IC9101, check each pin, neg. probe on a board ground one of the metal parts that slide in place when you take it off the tv, pos. probe on each pin, I believe three pins should show continuity to ground, the other 13 should not.

[nomoresonys]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

whats the rest of your model number UN65MU6290XXXX what letters go where the x's are?

[BiondicTV]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

I'm looking for the IC9101, the two switching transistors, Q9101C and Q6201C part numbers. Shop Jimmy doesn't have the repair kit in stock. Your help is appreciated.

[nomoresonys]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Damn that sucks, that's another thing I hate about sammys, they just break too damn easily.

[Chillin014]

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]

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.



My excitement was quickly squashed once I noticed very thin horizontal lines across the entire screen. I'm thinking this is unrelated to the repair and replacements I performed and possibly something wrong with the LCD panel.... I really don't know what to do at this point. Maybe I damaged it during removal. I think I'm going to slap it back together and just use it or sell it to someone who wants a nice garage TV.

Can't say I didn't warn you. I've done thousands of backlight repairs and this model by far is one of the sorriest POS I've ever had the mis fortune to have to repair and we just turn them down. The 6290F version is fine but if you see the POS 6290V version run as fast as you can because it's almost a fire hazard. Samsung should have some of the finest electrical engineers in South Korea and the MU series is the biggest failure money can buy. When you have to do a mod on the power supply every time you do a backlight replacement somebody didn't do their job right. And I refuse to fix your JUNK.

Agree. It's been a good learning experience for me but this is too much hassle.

Part designator: Example
R1 means the desigantor of that particular resistor is assigned as R1, so that 1.7 Ohms resistor must have designator so you can put in the correct resistor at the correct location.

Oh! Yes I put them in the right places - R9211 and R9111. I forget the transistor locations.

[nomoresonys]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Hate samsung.

[brucetv]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Can't say I didn't warn you. I've done thousands of backlight repairs and this model by far is one of the sorriest POS I've ever had the mis fortune to have to repair and we just turn them down. The 6290F version is fine but if you see the POS 6290V version run as fast as you can because it's almost a fire hazard. Samsung should have some of the finest electrical engineers in South Korea and the MU series is the biggest failure money can buy. When you have to do a mod on the power supply every time you do a backlight replacement somebody didn't do their job right. And I refuse to fix your JUNK.

[budm]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Part designator: Example
R1 means the desigantor of that particular resistor is assigned as R1, so that 1.7 Ohms resistor must have designator so you can put in the correct resistor at the correct location.

[Chillin014]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Just curious, what is the designator for the 1.7 Ohms resistor?

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.

[budm]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

Just curious, what is the designator for the 1.7 Ohms resistor?

[Chillin014]

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.

This would re-affirm my concern about damaging the LED during installation. I guess I'll be taking it all apart again and maybe I can salvage an LED from my old strip and rework it.

[Chillin014]

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.

[nomoresonys]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

A lot of times you can turn the backlights down in the menu even in the service menu, on a couple of my older tvs, not sure about the newest, I'll have the settings turned down and when I check them periodically, they have managed to jump up to 100 percent (vivid) again, with the pretty simple resistor mod, you don't have to worry if it has jumped up to the danger zone. They have been doing it for quite a while now, there's some on youtube.

[Chillin014]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

I believe the idea of using those bigger ohm resistors is to lower the current because a lot of manufacturers have way to much flowing and that's why the backlights fail prematurely, only reason I can think of WHY they do it is to break the tv in hopes that you will buy another from them. Can't see their logic tho, cuz the last thing I would do is buy a tv from the same company that planned my tv to break 2 months out of warranty.

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 the new LEDs so I used my LED tester to power them from the harness and they seemed to turn on but couldn't tell if the entire strip was lighting up.

Will await the repair kit and replace as much on the board as I can and try again.

[nomoresonys]

Re: No back light on Samsung UN65MU6290, Need help modifying Power Supply Board.

I believe the idea of using those bigger ohm resistors is to lower the current because a lot of manufacturers have way to much flowing and that's why the backlights fail prematurely, only reason I can think of WHY they do it is to break the tv in hopes that you will buy another from them. Can't see their logic tho, cuz the last thing I would do is buy a tv from the same company that planned my tv to break 2 months out of warranty.