EU55JS9000T black screen and sound good

[Davi.p]

Re: EU55JS9000T black screen and sound good

i don't like downloading big files.. can you report connector signals? how do you make the screen test? Standard RC or service RC? can you post a photo of the OCB cable? especially the connector.. are you sure the replacing ocb cable is good?

[totof]

Re: EU55JS9000T black screen and sound good

I make the tcon test with a service RC (it's a RC bought by my colleague, the tv is his).
Some photos of the tv during the test.
A photo of the one connect cable.

[Davi.p]

Re: EU55JS9000T black screen and sound good

you must show the tables of the main power board, the orange one..

[totof]

Re: EU55JS9000T black screen and sound good

The connector pin of power board

[Davi.p]

Re: EU55JS9000T black screen and sound good

OCB has a short circuit that disables the screen (12v off> tcon off) that disables the dim signal to the led driver board (backlight off).. since you are not a technician you have to get a replacement ocb.. 12v on MB maybe remains on because of a protection circuit at valley of the screen switcher mosfet..

[totof]

Re: EU55JS9000T black screen and sound good

Thank you Davi.p
Whether the OCB is connected or not I have 12V on the fuse at the input of the tcon.

Before bringing me his TV, my colleague went to an approved Samsung repair center but the technician didn't really look because the TV was too old for him. He tried another cable and another box but same result. But the technician didn't really know if his cable and his box were really functional.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Check up on the fan in your ocb, make sure it's clean and functioning properly.

[Davi.p]

Re: EU55JS9000T black screen and sound good

Whether the OCB is connected or not I have 12V on the fuse at the input of the tcon.

This changes things..

because the TV was too old for him

that man is ridiculous..

He tried another cable and another box but same result. But the technician didn't really know if his cable and his box were really functional

so this does not change things..

Carefully if possibile, safe, test the connector for the ocb on the main board to find the 12v feed pins, then connect a protected 12v test psu to the ocb to see if it goes into protection..

[totof]

Re: EU55JS9000T black screen and sound good

The fan was a little dusty and I cleaned it, it still worked.

Whether the OCB is connected or not I measure 12V on pins 25 and 26 of CN201

[totof]

Re: EU55JS9000T black screen and sound good

OCB has a short circuit that disables the screen (12v off> tcon off) that disables the dim signal to the led driver board (backlight off).. since you are not a technician you have to get a replacement ocb.. 12v on MB maybe remains on because of a protection circuit at valley of the screen switcher mosfet..

Yesterday I had the opportunity to try another one connect cable and the result is the same, namely that the backlighting turns off immediately as soon as the OCB is connected. So it is not a cable issue.

I checked the B13V signal on CN201 (pin 25,26 on main board side) and I see 12,73V when OCB is not connected and 12,67V when OCB is connected.
It's a little below 13V but it might still be normal, I don't know.

I'm following up on any leads that could help me find the origin of the problem.
I have been looking for the OCB card diagram for several days but it is nowhere to be found.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

The socket on the tv that you plug the cable into may be damaged, check it over.

[totof]

Re: EU55JS9000T black screen and sound good

I checked the connections on both sides, no problem detected
I measured the voltages on all the self on the OCB board.
L203 = 5.1V
L201=1.51V
L208,L209=12.3V
L901=1.16V
L304.305=0.92V
L302=0.89V
L802=0.05V !!!!!!!!!!!!
L401=1.09V
L402=0.97V
L202=3.3V
L404=0.90V
L403=1.8V
L307=0.99V

Maybe a problem on L802 but I don't know what it's for because I don't have the card schematic.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Guess the possibilities are, bad cable but you said you tried a good one, bad ocb, maybe the guy who tried a different ocb had a bad one or one that was incompatible, I would check as may components as I could on the ocb, bet one is bad.

[totof]

Re: EU55JS9000T black screen and sound good

I checked the capacitors for short circuits and found several with low resistance:
- C373, C377, C381, C382, C383: 36.6 ohm
- C3318: 0 ohm
- C1014: 36 ohm

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Ok, that's part of the battle, now to just find someone with a properly functioning ocb to compare with, I have no idea what those voltages should be, have always stayed away from those ocb tvs.

[totof]

Re: EU55JS9000T black screen and sound good

The problem is that this OCB model cannot be found, either new or used.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Looks like they run very hot with little ventilation if any, if I had to use one that worked, I would leave the cover off and also get some air blowing on it to try to keep it cool.

[Davi.p]

Re: EU55JS9000T black screen and sound good

one inductor with no voltage is normal, is for the Sat input/output

[totof]

Re: EU55JS9000T black screen and sound good

one inductor with no voltage is normal, is for the Sat input/output

Thanks, no need for me to focus on that side

[totof]

Re: EU55JS9000T black screen and sound good

Looks like they run very hot with little ventilation if any, if I had to use one that worked, I would leave the cover off and also get some air blowing on it to try to keep it cool.

I notice that the backlight cuts off a fraction of a second after plugging in the OCB cable, it's really instantaneous, while the sound from the TV comes several seconds after plugging it in.