Samsung QE50Q50TUA power cycling.

[stav242]

I picked up this Samsung 50" QLED, QE50Q50TUA.
MB is BN41-02756C.
PB is BN44-01058A
no dedicated TCON - its on MB.

fault symptoms are:
TV powers on, Backlights come on, no picture, then restarts and repeats.

Power from PB to MB is good, 13V is present as detailed on the PB board diag info.

i can find some 1.3v and 3v power on the MB, but nothing higher.
there is no VGH on the buffer boards, again some 1.5v and 3v, nothing higher.

found this SMD device (diode ?) which doesnt register on ESR/cap/diode tester, removed it and still tests the same.

SMD code : NE1 EN7
label near it : IC4000_UT

cant find it anywhere -any suggestions what it might be and what i could replace it with ?

[lotas]

Re: Samsung QE50Q50TUA power cycling.

It's not a diode, it's a Polymer Chip Tantalum Capacitor.

[stav242]

Re: Samsung QE50Q50TUA power cycling.

It's not a diode, it's a Polymer Chip Tantalum Capacitor.

ok, thanks.

ill see if can find a suitable replacement from a spare board.

[stav242]

Re: Samsung QE50Q50TUA power cycling.

replaced with a 33uf 50v cap. no change though.

anywhere i can find a circuit digram for the MB ?

[alfatv]

Re: Samsung QE50Q50TUA power cycling.

Disconnect the cable from main board to panel and see if it's still restarting

[lotas]

Re: Samsung QE50Q50TUA power cycling.

Disconnect the LVDS cable and try turning on the TV and see if it reboots.

[stav242]

Re: Samsung QE50Q50TUA power cycling.

if i disconnect the LVDS cable the set boots and doesnt reboot. (optical port LED stays on continuous).

if i reconnect the main LVDS cable, but then disconnect the right (view from the rearview) side buffer board from the left buffer board. the set still boots.

ive checked all caps on the buffer boards, cant find any shorts.
no signs of panel damage and COF cables look fine.

i was looking for 12v or 24v on the buffer board, but cant find anything - which led me back to the MB.

is this likely to be a buffer/panel board short - or a MB power fault ?

[lotas]

Re: Samsung QE50Q50TUA power cycling.

The problem is in the panel itself, take a photo of the full buffer strips and on which strip, if it is connected, the reboot occurs.

[Davi.p]

Re: Samsung QE50Q50TUA power cycling.

Disconnect the LVDS cable and try turning on the TV and see if it reboots.

Disconnect the cable from main board to panel and see if it's still restarting

in our country in this case we say Flic Floc!

[stav242]

Re: Samsung QE50Q50TUA power cycling.

The problem is in the panel itself, take a photo of the full buffer strips and on which strip, if it is connected, the reboot occurs.

ok, photos attached.

2x of main board with LVDC connector - no markings i can identify any volatages to check.
2x of left board - this is connected and TV powers on, optical port on MB lights up constant, remote works, but no sound or picture.
4x of right board, this connects to leftboard, and when connected the TV reboots every 10 seconds. - can see the MB optical light and backlights power cycle.

ive checked the cof tabs, cant see anything visually wrong, no burns or damage.

this TVs a QLED and cant immediiatley see hwo to get the LCD panel away from the frame to do a more intrusive panel check atm ... will see if i cant figure it out.

[alfatv]

Re: Samsung QE50Q50TUA power cycling.

Looks like another TU.
Why do you need to remove the panel?

[nomoresonys]

Re: Samsung QE50Q50TUA power cycling.

It's a samsung QExxxxx POS, problem is the panel as stated, don't really need to look at the backlights, so no reason to tear all the way down.