Samsung UE49MU6120 no boot, no spy led, blinking backlight...

[Davi.p]

Hi folks, the set is from my brother house, unfortunately i'm repairing 1 tv, 1 pc, 1 tablet, 1 Stereo receiver at the same time, all house's bench/table busy, i eat like an horse, and i'd like to know sure experience from other techs about this, i don't like to transport it to my house and it ends it is bad backlight waiting months for parts and so on..
The blinking is only on the left side, no answers from remote, right after plugging in, back story of tv it had some slight B.L. problem, some shadowing in the bottom of image, maybe burnt sheets.. i really hope it's the same old spi flash issue, that happened suddenly after left in standby with the damned HOT of this August, i found it doing so in the tavern (is it the right word?) , i guess it is something heat related cause i found in my memory that this maybe happened once in the past year August but restored itself to working condition, in october tv moved to a cooler room.... that's all, bye..

[Davi.p]

Answering myself them are the bad leds..

[lotas]

предыстория телевизора, у него была небольшая проблема с BL, некоторое затенение в нижней части изображения.

Based on this sign, it is clear that the problem is in the backlight...

[Davi.p]

thanks lotas, i'm searching the forum for compatibility of panels of UE49MU6400KXZT and mine, i found the donor tv on sale, i need probably also spare diffuser sheets..
CY-KK049HGEV5H is my panel..

[lotas]

At the end of the number all the letters are correct (KXZT), otherwise even Google doesn't know such a model?

[Davi.p]

Ok found the needed information by an ebay sale of led bars, full of models list, it's enough for me, now it could be helpful of finding a video guide on the bar substitution, i'd like risk zero cause i heard of Samsung putting terrible glue on some models..

[Davi.p]

To correct myself , the right model name of mine is UE49MU6400UXZT, the one i wrote was bring me by brother years ago, i checked back.. sorry...

[lotas]

So what is the problem, how to replace the backlight, the panels are the same in size “49” (the panel manufacturers are different...), the reflectors (plexiglass) are also the same (you need to look, there are straight panels in these models, and there are curved ones) ...

[Davi.p]

The tv took a "saet" i guess, or a mains spike because if it was only BL the tv turned on, maybe i have to reprogram also the memory..

[lotas]

Usually in this "MU" series, if the firmware fails, then the TV would not turn on at all and the standby LED would not light up... but here we need diagnostics to begin with...

[Davi.p]

The backlight leds are bad, yesterday i fixed my desoldered rudimental LED tester, self built, left bar lights up, right one don't.. tried to slip out the pin 1 Fail count from PSB hoping it was the reason of a no boot in protected mode, but it happened nothing.. maybe i'm dumb, but is also fu**ing HOT here these days, i don't remember if i have detached LEDS and given power, or detaching Fail Count pin i reset a protection, anyway MB is good, it boots and i can see menus using torch, i had also grabbed the stby SW using TL866II+ and clip (jumper wires on two crystals).. who needs can ask.. i want only a Rolex in change..
here it is...
(For moderators if it can be changed model on title: UE49MU6400UXZT)

[Davi.p]

I'm watching now how to gain acces to led bars, i think front screen bezel is glued onto lcd panel and must be unglued usign hair dryer (phon) or hot air gun, which one? i need to search a video on how to or some info..

[Davi.p]

OMG! Another problem pops in mind! If i unglue it i have to procure a perfect replacement biadhesive, and have to carefully remove old one!...Damned Samsung..

[Davi.p]

Samsung assistance center told me used led bars can't be removed from used tv cause them breaks..

[Repairtechlcd]

It's a common fault.You should find new backlights online.The only problem is that most probably the light guide plate is probably cracked and you will have to get one from a Samsung service centre as if you buy it online it may sustain damage during transport.

[Davi.p]

i already wrote that there is a ceacked panel donor tv on sale, the seller told image was perfect, the hard part is how to do the process.. i find no videos about it.. thanks

[lotas]

i already wrote that there is a ceacked panel donor tv on sale, the seller told image was perfect, the hard part is how to do the process.. i find no videos about it.. thanks

Just rearrange your original matrix to a donor TV...

[Davi.p]

Oh great, that seems a very good hint, thanks Lotas..
just to speaking a bit techincally, when i opened the tv i had examined a bit the power supply, i found 2 components named on board SA001 & SA002, similar to tht resistors, black, in series with the 2 AC line input traces, them are Surge Absorber almost 100%, them are shorted, measure 0ohm, them shortens the 2 input filter coils, i think their purpose is to make the varistor at the input to work faster in case of surge, now it's late night, i can't do photos sorry, i think my guess that backlight has been hit by surge is right.. what do you think?

[Davi.p]

Forgot to say, i saw This video, where clearly see that the front bezel can be removed together with lcd Matrix without unglueing them.. (1 hour and half video!)

[Davi.p]

Another theory, input filter is a dual way filter, what can happen if the filter is bypassed like here for a long time? I found myself the tv broken when i came to my brother's house, he was on vacancy, no circuit breakers in off position, so i think the input varistor did not entered, maybe those.absorbers was shorted by years and in long time the leds has been affected by input filter disabled.. (?)