Samsung UE55MU6120K Boot loop with backlight no video

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Yes, dc to dc converter, somehow I put it in wrong and came up with this, didn't think that seemed right, lol: https://www.aliexpress.com/i/3256803...apt=4itemAdapt

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Cool, bet that was it, damn solder crack on that little bugger, didn't think it was anything major because it ran for 30 hours straight.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

This is a DC / DC converter for powering the panel, there may be a problem in tying this converter with ceramic capacitors.

Yes it's a power main control chip, the nearby capacitor had a cracked solder, I re-soldered it, let's see it works for now

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

This is a DC / DC converter for powering the panel, there may be a problem in tying this converter with ceramic capacitors.

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

so I wonder what exactly it could be, do any of those little mlc caps test short, maybe check those resistors too, what is that chip the ethernet switch?

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

he seems to be the problem, probably some cracked welding since it now works after being heated

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Actually it probably is the mainboard, well there's your proof, posted this after the above post, as in wrote this before your above post so didn't see that til after I posted.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Well, now try, with each lvds cable (from the left, then from the right).

i heated this area up with 350 degree hot air and the tv started working again

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Well you can replace the mainboard 47 times but it still won't fix it if the problem isn't the mainboard.

maybe you missed some pieces :-)

[lotas]

Re: Samsung UE55MU6120K Boot loop with backlight no video

I'm back, I bridged the points indicated by you (without connecting the display flats) and the TV turns on and off repeatedly as always, at this point I buy a motherboard once and for all

Well, now try, with each lvds cable (from the left, then from the right).

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Well you can replace the mainboard 47 times but it still won't fix it if the problem isn't the mainboard.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

You didn't seem to put a jumper there.

I'm back, I bridged the points indicated by you (without connecting the display flats) and the TV turns on and off repeatedly as always, at this point I buy a motherboard once and for all

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Evidently if you have forced TCon-Ready signal and something heated on the main board, the main goal is to locate the short circuit, actually it can also be on a small cap on mainbboard, thethermal cam helps, but also if you go to the supermarket you can ask the shop man for a piece of adhesive thermal paper for the fiscal record, if the heat comes from an inductor only on mb then better to search on the panel distribution boards

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Don't waste time with thoughts of bad soldering joints and Macumbeiras... the problem reseats on the display and obviously without surgeries and with the eprom comparison equal you have a alternating defect maybe little heat related, maybe to gate COG , better to start the tespoint searching, clock lines, and prepare masking flats with tape..

I maskered the world to no avail last time, I'll see tomorrow anyway a bit and I do various tests

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

doubt it very much, can not recall a shorted panel ever not working then working for 30 hours.

[Davi.p]

Re: Samsung UE55MU6120K Boot loop with backlight no video

Don't waste time with thoughts of bad soldering joints and Macumbeiras... the problem reseats on the display and obviously without surgeries and with the eprom comparison equal you have a alternating defect maybe little heat related, maybe to gate COG , better to start the tespoint searching, clock lines, and prepare masking flats with tape..

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

lmao...hate when that happens.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

probably won't work but if it's still on the wall try a quick reset before you wrestle it back off the wall, unplug tv, hold power button for 30 seconds and try it, prolly no joy, then off the wall again.

already done unfortunately it doesn't work, i have to disassemble everything again

[nomoresonys]

Re: Samsung UE55MU6120K Boot loop with backlight no video

probably won't work but if it's still on the wall try a quick reset before you wrestle it back off the wall, unplug tv, hold power button for 30 seconds and try it, prolly no joy, then off the wall again.

[fanaticgames]

Re: Samsung UE55MU6120K Boot loop with backlight no video

not sure, but probably retaining a lot more heat if it's snug against the wall, well was it sitting straight when running for 30 hours as in same position as on the wall.

It just didn't turn on, plugged into the wall...turned on and baamm rebooting like always