Samsung UE48J6200K - No image but sound

[Diah]

This testing I have it pending. I need my wife not to be at home as the test requires "some space". :-)

I'll let you know the outcome during the weekend.

Thanks Diah for this suggestion.

i do understand..... THX GOD i am again alone..LOL

[lotas]

LOL.... lotas T-CON never being Voltage or currents,,, so what are all these muscle training you are showing here... LOL.... T-CON must an Panel connected... and must too the 12V VCC from it own PSU to match Freq. .... this is MUST if one want to handle T-CON in case he didn't have in hand Oscilloscope ... end of muscle training show.

Who told you this, you can easily run this t-con on the table, with a jumper installed and by applying 12v to it, it should produce voltage to power the panel, and when you repair the T-con, you always take the original power supply from the TV, which should I check t-con?

[Diah]

Who told you this, you can easily run this t-con on the table, with a jumper installed and by applying 12v to it, it should produce voltage to power the panel, and when you repair the T-con, you always take the original power supply from the TV, which should I check t-con?

i don't know where you read this but its impossible... forget it...
to switch low V. you need P+ P- signal feed to each channel at T-con and this supplied from external which it have own socket.... don't listen to web crazy they did no one can only the manufacture of the LCD

if you do it and you said yes i did i will believe you 0.1%

[lotas]

And we will ask Francesc V. whether it turned out to launch t-con or not.

[Diah]

And we will ask Francesc V. whether it turned out to launch t-con or not.

deal... your sign will be 3 LED on T-con turn on.... sure they are but are this tell you the panel rubbish

[lotas]

Yes, first we will check the t-con, after we make sure that the output voltages are normal, we will install the t-con with the same jumper in the TV and connect one cable at a time to the panel and determine which half of the panel is not working.

[Francesc V.]

Yes, first we will check the t-con, after we make sure that the output voltages are normal, we will install the t-con with the same jumper in the TV and connect one cable at a time to the panel and determine which half of the panel is not working.

Yeah!!! This jumper on RM15 made my day. I have had the T-CON working on my desk with the 3 leds on (BIG THANKS TO LOTAS). I have checked the voltages marked on the PCB (1.2, 1.8 & 2.5V checkpoints).

Now that I have installed back in the TV, I am testing both ribbons without no final conclusions.

- LED2 switches off after some seconds if both ribbons are connected.
- LED2 keeps switched on if 1 ribbon is connected.............doesn't matter which one. I am testing rounds of 2 minutes if something weird happens.

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Update
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When left ribbon is connected, other part of screen remains black.
When right ribbon is connected, other part of screen remains white.

Also, as long as it was about minutes and minutes of testing, I've left TV unattended and only when left ribbon has been connected, 2 times I've found the TV switched off (I am marking in the picture as possible issue in this part of the panel)

Let me know if you want me to test some additional voltages from the T-CON. Or everything suggests that is something wrong in that section of the panel.



Regards,
Francesc.

[Diah]

from T-CON Photo RM13 are the bypass fault. to let T-com don't cut off GPU signal

[lotas]

Now it is not known whether your T-con is working or is already malfunctioning after your experiments (installing without knowing what jumpers, power supply and grounding of control points...), if the LED goes out, it is not the t-con protection that is triggered, disconnect the cables from t-con going to the panel and first check with a multimeter if there is short or low resistance on the ceramic capacitors on the buffer strips of the panel..

[lotas]

from T-CON Photo RM13 are the bypass fault. to let T-com don't cut off GPU signal

What kind of RM13? And how does it work around the defect?

[Diah]

What kind of RM13? And how does it work around the defect?

from his last test.,, have one side white and other black. the same to other side which its black become white... so there are cut off of GPU signal ( Image)..
as i wrote before he need to disconnect the LVDS and keep your by pass in place and feed the T-CON 12V VCC direct from PSU to let the T-con being independed and the SPI could turn on the screen in pattern.

[lotas]

And also, carefully inspect the contact pads on the cables; over time, they dry out and when removed and installed, they break, move, and these lamellas on the cable short circuit each other.

[Francesc V.]

Ok..........I had time to test your suggestions.

First of all I took some time to measure all components from the left buffer strips PCB. Nothing seems shorted or with low resistance. Important to mention that when I was measuring all these components with the strip disconnected from TCon, I was measuring "no ground" from one side of the capacitors, whereas, when connected..........one side from capacitors was pointing to ground and other had several K ohms.

Second test I performed "finally" was to disconnect Tcon from Mainboard and inject 12V. In parallel, TV was switched on to have backlight. The result has been a nice blank screen. Not sure if you where expecting a whole white screen there.

Regards,
Francesc.

[Diah]

Ok..........I had time to test your suggestions.

Second test I performed "finally" was to disconnect Tcon from Mainboard and inject 12V. In parallel, TV was switched on to have backlight. The result has been a nice blank screen. Not sure if you where expecting a whole white screen there.

Regards,
Francesc.

remove yours by pass RM15 and do it again as you explained
Note you can do it also in half screen a time

[Davi.p]

To me is not clear the post 19, the status of led 3, if present an image.. etc..

[Francesc V.]

To me is not clear the post 19, the status of led 3, if present an image.. etc..

Yes, by unblocking the TCON I have been able to see picture and point the issue on left side of the panel (theoretically).


Right now, TV is working for an hour and I have done "anything" .

- Removing ribbons and clean them with isopropyl alcohol.
- Removing the jumper RM15.
- Playing with tape on the left panel ribbon with no success. Image was crap in all tests, but at least there was image :-)

Tired of no success with tape, I've removed the tape and installed back the ribbon.


Clear picture and sound for quite a long time...........it will not last very long, I know.

I will continue with the test suggested by Diah.......because maybe, and just maybe it's not the T-CON neither the panel. Saying this because during testing, the image freeze (a frame) was kept in the background in the meantime the realtime picture was playing (not sure if you understand what I mean).


Regards,
Francesc.

[Davi.p]

First things i want to say, right to be clear, the led 3 is for the presence of panel supply voltages, when led 2 is for tcon circuitry supply present, the first to be executive is the pmic, then it is energized the main chip, and last the panel, since some time the panel has flaws or it is right the tcon unable to drive it well (and this is the main point , se next) it happens that panel feed it is released, this is my point now, my recent findings tells that with no visual oxidation or shorted components on strip boards, the main goal for the protection circuitry is to unload the tcon supply part, that could suffer, and not to protect the panel, and my bet is that you have bad bga balls on the couple of ic on board, more than this, im wondering witch chip is the one under radiator, seems a memory, lcd tcon uses no big flash or ram, sounds strange.. has it FRC function in the same chip? High integration is typical of developing bga problems..


you have not clarified about led3 on the tests..

another point, by cheating the tcon feedback circuit, and disconnecting one side, you are unloading a certain amount the tcon, so led 2 and vcore stays on, but connecting both sides dcdc stages suffers and vcore is shut down

[lotas]

When you installed the jumper on RM15, did you have voltages at t-con approximately: VGH - (+27v), VGL - (-8v), VDD - (+3.3v), VDA - (+15v), VCOM - (+8v)?

[Diah]

T-CON are slave as well the Panel.... all what you are seeking after VGH/ VGL/VDD(VDA/VCOM will not present if there no GPU signal... that's all search after the source to make all of these present. as OP he did.

[Diah]

I will continue with the test suggested by Diah.......because maybe, and just maybe it's not the T-CON neither the panel. Saying this because during testing, the image freeze (a frame)

thought you did trick the t-con by RM15. which it trick also the MB to transfer raw data.. now the RAM on MB stick full so the frame will freeze... find the chance as it is on now to log in service menu and make hard reset to clear RAM / T-CON action