EU55JS9000T black screen and sound good

[totof]

Re: EU55JS9000T black screen and sound good

The diode D3301 is one side connected to GND and other side to B13V from OCB connector.

Marking code on the diode is D2 W5n. It is a zener diode but I don't know if it is the good voltage.

It seems D2 code is for 3,6V zener diode. I don't know what is W5n.

I desoldered the diode and it is identified as a diode with my tester.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

415 euros.
Much too expensive for my colleague especially for a used card.



I'm tracking the shorted C3318 capacitor because it's located just below the OCB connector. I removed it but it's not the one that's shorted.

Check that diode right beside it, go ahead and check it in circuit, see what it reads.

[totof]

Re: EU55JS9000T black screen and sound good

I'm tracking the shorted C3318 capacitor because it's located just below the OCB connector. I removed it but it's not the one that's shorted.

I did not understand what C3318 is for in any case there is 12.3V at its terminals and it is connected to the VIN pins of several ICs: Z3013PI, TPS54427 (x2) and TPS106041 (x2)
This is not the right way.

Complicated, very complicated (for me)

[totof]

Re: EU55JS9000T black screen and sound good

https://aliexpress.com/item/1005001530200726.html

415 euros.
Much too expensive for my colleague especially for a used card.

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

I'm tracking the shorted C3318 capacitor because it's located just below the OCB connector. I removed it but it's not the one that's shorted.

[lotas]

Re: EU55JS9000T black screen and sound good

My work colleague, who owns the TV, told me that one of the seller's selling points was that it would be easy to upgrade the TV and repair it with this external box.
Except that 8 years later the box no longer exists, it cannot be found even in the Samsung approved repair center.

https://aliexpress.com/item/1005001530200726.html

[nomoresonys]

Re: EU55JS9000T black screen and sound good

I steer clear of any proprietary bs like that ocb cable nonsense, just give me hdmi, rca, component, toslink, usb etc. And put them right on the tv so I don't lose them.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Just more of samsungs planned obsolescence but many seen this one coming.

[totof]

Re: EU55JS9000T black screen and sound good

It really sucks the way samsung did this model, they made that shitty hot ocb and put absolutely no other connection ports on the tv itself, so they gave the consumer no choice but to use it.

My work colleague, who owns the TV, told me that one of the seller's selling points was that it would be easy to upgrade the TV and repair it with this external box.
Except that 8 years later the box no longer exists, it cannot be found even in the Samsung approved repair center.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

It really sucks the way samsung did this model, they made that shitty hot ocb and put absolutely no other connection ports on the tv itself, so they gave the consumer no choice but to use it.

[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.

[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

[Davi.p]

Re: EU55JS9000T black screen and sound good

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

[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.

[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

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

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

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 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

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

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.