Samsung UE55MU6120K Boot loop with backlight no video

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Here I give you a photo of each half (left and right cable) where to isolate the CKV. Maybe it will be easier for you.

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

This jumper is placed to determine which half of the panel is not working, insert one cable and turn on the TV, then do the same with the other cable.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

I don’t know, it’s not clear where, in one place there is a point, and its inscription in another, now on which half is the defect in the matrix?
If the cable is inserted one of a kind, is there also a reboot?

at the point I indicated it does not restart, at the point you indicated it restarts, the flats are disconnected I have not tried to connect them

from the tests I did yesterday by putting the tape on the left side flat it didn't go out but you couldn't see anything anyway

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

I don’t know, it’s not clear where, in one place there is a point, and its inscription in another, now on which half is the defect in the matrix?
If the cable is inserted one of a kind, is there also a reboot?

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

now I have connected them correctly and the tv keeps restarting all the time, so the motherboard is bad??

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

T-RDY1 and T-RDY3

yes, jumper done, the tv doesn't restart and works, so it's definitely the faulty panel

EDIT

I used this, isn't he?

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

T-RDY1 and T-RDY3

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

It's clear, now put a jumper between T-RDY1 and T-RDY3 (imitation of panel connection) and check also with the loops disconnected (with left and right).

jumper done, it works

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

this is what i'm trying to explain from the beginning, i recap:

(with TV off)

I turn on the TV only with the left flat connected and it turns on

I turn on the TV only with the right flat connected and it turns on

I turn on the TV with both flats connected and it goes on and off endlessly

same thing even if I disconnect the flats with the TV on, just disconnect any one and it stays on

the problem occurs only when both flats are connected



Damn

It's clear, now put a jumper between T-RDY1 and T-RDY3 (imitation of panel connection) and check also with the loops disconnected (with left and right).

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Lotas i have tested it on a Panasonic with Samsung panel, the image appears and stays on with many artifacts and a coil starts to heat on tcon.
Fanaticgames, there's no need of the uart, the fault is in the screen, this is clear for who has experience enough, the uart is possible maybe but it's a very long process to enable it..

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

When you disconnect which cable (left or right), does the TV stop overloading?

this is what i'm trying to explain from the beginning, i recap:

(with TV off)

I turn on the TV only with the left flat connected and it turns on

I turn on the TV only with the right flat connected and it turns on

I turn on the TV with both flats connected and it goes on and off endlessly

same thing even if I disconnect the flats with the TV on, just disconnect any one and it stays on

the problem occurs only when both flats are connected

The UART is locked in the firmware itself.

Damn

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

When you disconnect which cable (left or right), does the TV stop overloading?

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

The UART is locked in the firmware itself.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

to make things short, locate on MB two test points named T-RDY1 , T-RDY3, join them, in this way protection is disabled, now turn on tv and watch on to the screen's small boards if something gets hot or smokes, prepare to turn off tv rapidly, hope that there is a cap or diode in a half short state..

but there is no way to make a uart connection to the motherboard via usb serial ttl to understand the reason for the reboot, before reaching these extreme attempts? on consoles like ps4 or phones it's useful, on tv's i don't see many arguments about this

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Points T-RDY1, T-RDY3 do not disable protection, they are intended for something else.

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

to make things short, locate on MB two test points named T-RDY1 , T-RDY3, join them, in this way protection is disabled, now turn on tv and watch on to the screen's small boards if something gets hot or smokes, prepare to turn off tv rapidly, hope that there is a cap or diode in a half short state..

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

I don't know if it can be useful as information but someone has already repaired or attempted to repair this motherboard in the past because this component had its soldering redone (I don't know if it was changed or just re-soldered)

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

+10


could you please stop this stupid suggestion..

as Lotas said ESD diode... but if one shorted.. you will have cell shorted.. the solution block all ckv from the top LVDS socket at MB side. other wise this is rubbish Panel.

even if i want to do it as individual ckv lines? on the motherboard I don't see any ckv indication

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Do not try to supply 12v anywhere, otherwise you will completely kill your panel and motherboard! Check with a multimeter for resistance these leads on the protective diode assemblies relative to gnd.

just check that they are not shorted? because I had already tested in continuity mode

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

2 of the best professional techs here just advised against it and stated what will happen if you do that, so WHAT don't you understand about it davipee.