Samsung UE55MU6120K Boot loop with backlight no video

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Now that we have listen to the others would you like to follow my advice? what do you think?

to inject a voltage from 12 to 15 I need a bench power supply that I don't have, I thought I'd solve it in another way

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

no read my post about the jumper wire..

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

no read my post about the jumper wire..

I've already bridged those points

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

I've already bridged those points

kept on even more than 3 minutes nothing heats up on the display board, in fact I tried 5 times, 4 times the TV restarts the same repeatedly, only once it stayed on, the only thing I noticed was a hum in this area but nothing else

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

so to be more clear, TRDY jumpered , but not the ones told to you by Diah, the ones actually marked as them, no tape on the flats, and it keeps restarting? i don' think so, i remember you posted only one picture clear of TRDY point, and the other one?

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

so to be more clear, TRDY jumpered , but not the ones told to you by Diah, the ones actually marked as them, no tape on the flats, and it keeps restarting? i don' think so, i remember you posted only one picture clear of TRDY point, and the other one?

read above, united points (the correct ones I assume because without flats they don't restart), with all flats the result is that only once it doesn't turn off, it keeps restarting with the variant that emits a bad buzz in that area of the motherboard , all components are cold except for the cpu which is slightly warm

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Ok, so without a bench PSU i can only suggest this type of test, remove each one of the diode packs on the screen's boards, test entire tv after each removing, if it doesn't change (i think is not there the problem), repeat same thing also with the bigger caps that are probably on the Avdd/15v line..
just to be clear, the buzzing noise confirms that there is a short circuit on the screen

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Ok, so without a bench PSU i can only suggest this type of test, remove each one of the diode packs on the screen's boards, test entire tv after each removing, if it doesn't change (i think is not there the problem), repeat same thing also with the bigger caps that are probably on the Avdd/15v line..
just to be clear, the buzzing noise confirms that there is a short circuit on the screen

for information when I did the tests with scotch tape I also isolated the vcom and avdd signal and it always restarts

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

and which is the question? the masking suggestion is not by me, you must ask to the owners, avdd and vcom must not be isolated

[PaolinaSparks]

Re: Samsung UE55MU6120K Boot loop with backlight no video

nothing changes, it always restarts, i guess the ckv lines have nothing to do with it at this point

please excuse my stupid question
But to really rule everything out please tell me which photo is which cable and if it is mainboard side or gate driver side.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

please excuse my stupid question
But to really rule everything out please tell me which photo is which cable and if it is mainboard side or gate driver side.

the tape was put on correctly

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

and which is the question? the masking suggestion is not by me, you must ask to the owners, avdd and vcom must not be isolated

the question is isolating those 2 lines (avdd and vcom) shouldn't it turn on and not restart if the short is there? do you think the short could be on avdd? so your suggestion is to inject the 15v directly on one of the two display boards with everything connected?

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

if masked avdd or vcom the mainboard circuitry goes in trouble and reboots, injecting on avdd can pop a suspected bad cap so you can replace it, but 12v are enough, the important is that 1,8v/3,3v must be present, therefore cof are powered.. prepare to switch off everything when you see smoke, but pay attention first on screen's glued ribbons, them must not burn!

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

if masked avdd or vcom the mainboard circuitry goes in trouble and reboots, injecting on avdd can pop a suspected bad cap so you can replace it, but 12v are enough, the important is that 1,8v/3,3v must be present, therefore cof are powered.. prepare to switch off everything when you see smoke, but pay attention first on screen's glued ribbons, them must not burn!

the 3,3 are present only for a moment as the tv restarts every 2/3 seconds

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

is there any 1,8v? you must check which of these two voltages are present on the smaller caps near the source cofs therefore the ribbons on the bottom side, that tension must be provided constantly to the panel toghether with avdd

[PaolinaSparks]

Re: Samsung UE55MU6120K Boot loop with backlight no video

the tape was put on correctly

I hope you forgive me. How could I doubt you

[PaolinaSparks]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Nope, I didn't find any shorted capacitors

Have you tested the resistors and diodes too?

And I can still recommend disconnecting the Bluetooth module. A defect in it can also cause the error.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

is there any 1,8v? you must check which of these two voltages are present on the smaller caps near the source cofs therefore the ribbons on the bottom side, that tension must be provided constantly to the panel toghether with avdd

I check as soon as possible, I test as soon as I can with a bench power supply and you update

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

I have an update, as usual strange things only happen to me, I left the TV off for 3/4 days with the bridge on points RDY1 and RDY3 today I borrow a friend's thermal imaging camera and turn on the TV (with the bridge and the connected flats) and immediately after 1 second I see these 2 components (in the photo) heating up so much, I disconnect the bridge and turn the TV back on and it works, the whole display works, you see

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

You didn't seem to put a jumper there.