Samsung UE65MU7003U / BN41-02568B - HDMI No Signal

[natiz]

Following a power surge, the HDMI ports on a UE65MU7003U no longer work, no matter the port or the source - it shows No Signal.
The other functions work well (eg Netflix app, etc.), its just the HDMI ports.

Is the BN41-02568B board salvageable? Any leads before I open the heatsink cover? board replacement?

[CapLeaker]

Nah. All the HDMI crap goes under the heatsink. That heatsink has to come off. Then it depends if it goes straight to the main IC or if there is an HDMI switch in between.

[Davi.p]

today's MB of Samsung and most of others supports almost 80% of functions in the SoC, comprised hdmi mux/decode, so the SoC is the faulty part 98%, the rest of the % is to check those 6 pins sot23-6 ic near connectors, if them are correctly fed or it's supply line is low and then them generates error in the external video source ...

[natiz]

Ok plot twist - I replaced the board - same issue - no signal on hdmis, while apps working properly.
I checked the supply voltage from the power supply to the board, while the board was disconnected - got ~12v on all of them.

Could the power supply be affecting the hdmi ports? Ordered one but will take some time to arrive.

[Davi.p]

noooo, your hands really really holed , a power supply board is easy to test , i hate this way of repairing, anyway, have you tested the video sources also with another tv?

[natiz]

Yes of course, they work properly on another tv

[Davi.p]

very essy test to do: cennect everything , turn on tv , test the 13v output, if it's about 12,7v then psb is ok and you can cancel the purchase, possibilities? replacement main board also faulty, or...galloping aging and you put back original MB instead of new one.. :-(((

[natiz]

Connected the old board back. All A13V pins measure around 12.75v while tv was on and connected to hdmi source. The “fault count” pin measures about 3.3v, not sure what that means.

The replacement board was brand new from the local samsung importer, I refuse to believe it was faulty but who knows

[Davi.p]

We can easily examine the situation in few steps:
- main board is fed by only 13v line and is fully ok
- fail count is almost probably a signal coming from backlight ic that tells to MB to disable a faulty backlight
- no good reason why a fail detected by psb must stop the hdmi to work
-psb main ps circuit is always unable to self diagnose, or the only check i seen is the low mains output, the backlight ic usually do, the ac check tells the cpu to shut down, it does not happen..

final considerations: so ruled out the psb unless main ps ic has built in autodestruction routine that tells mb to go mad, but why don't implement it easier in the mb software?

actions: if you feel doubting this planned obsolescence is real, take a small needle, slip out the fail count wire terminal , test again tv.. or if 3v is still present onto wire, put it at ground

[nomoresonys]

I'll give the same advice as always, start simple. With the new board, If you have not already do a firmware update, no joy do a factory reset, just two simple things to try.

[Diah]

HDMI Cable damage.... change it with trusted working one.... nothings bad at your TV or source

[nomoresonys]

Good point Diah, he said he tried on another tv but wasn't specific if another cable was tried.

[natiz]

Thanks for the advice!
The HDMI cable is not damaged, its not one cable or one source - all the devices/cables were tested on other TVs and are working properly.

with the old board connected, I disconnected the backlight cable from the psu, still no signal and "fail count" now measures around 2.3v.

I connected the new board, did a factory reset, setup wifi, and did a software update - same result - all hdmi ports no signal.

[Diah]

be more clear---
you put replacement MB and the issue same ! and what had power boards to do with HDMI if Tv working ?
what do you mean No HDMI... did you have sound ? did the screen remain black or it show Text No Signal..

BTW yours Tv HDMI version 2.0 did you used source and Cabel with same version 2.0 or yours was old one 1.4 version ?

[natiz]

Not sure I understand the first question.
The tv reads “No Signal” - there is no sound and no black screen. It doesn’t recognize that there is a device connected.
Both cables and devices are version 2.0.

[Diah]

Not sure I understand the first question.
The tv reads “No Signal” - there is no sound and no black screen. It doesn’t recognize that there is a device connected.
Both cables and devices are version 2.0.

the first things i asked as you wrote... you replaced main boards and its same issue.... correct ?

did you try Tuner signal areal or sat ?
can you select HDMI 1 or 2 or 3 from INPUT screen ?

[nomoresonys]

And you made sure that the numbers on the sticker of the new board match the old board, not just the silkscreen board numbers?

[Diah]

And you made sure that the numbers on the sticker of the new board match the old board, not just the silkscreen board numbers?

dont bother.... later one come and say thanks to i found the reason.... this threat just like trick.. no more from my side.

[nomoresonys]

Hmmm, not sure what to think, I'd hate to think that someone is going to the trouble wasting their time, just so they can waste our time, suppose anything is possible tho.

[Davi.p]

Do you understand my post?