Samsung UE/UN55ES6xxx - black screen with backlight on.

[mirokulaz]

Hi all,

I got my hands on a Samsung UE55ES6100 from a friend.

When I got it, it was showing distorted colors and double images. I expected to possibly solve the issue with the replacement of the TCON.

After opening it and just repositioning the ribbon cable everything worked perfectly fine (good picture), but after I had everything together again, it showed the very same error. Then out of a sudden it did not show picture anymore (sound still worked).

I replaced the TCON but still no luck. I did some further investigation on the tcon board.

Disconnected Panel: TCON RDY = 3,3V
Connected Panel: TCON RDY = 0V

I noticed that there are some capacitors on the LCD-connecting board (do not know how to name it), that are connected to GND on both ends (marked red). This looks suspicious to me.

When I turn on the TV with connected panel, I cannot measure any voltages (usually 17.5V) on the adjacent capacitors (marked blue).

I tried on the tcon side as well and noticed that I have good voltages there when I disconnect the panel, but when I connect it again, I will not see any voltages there.

Has my panel a short circuit or has my tcon replacement board also a defect? Any suggestions welcome.

thanks in advance

Miro.

[dskall]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Check across those caps on your panel board. Don't know what tv's but several have had shorted caps.

[budm]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Yep, just check the RESISTANCE of the suspected caps to see if they show leakage resistance or shorts.

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Check across those caps on your panel board. Don't know what tv's but several have had shorted caps.

Yep, just check the RESISTANCE of the suspected caps to see if they show leakage resistance or shorts.

Thank you. I already know that the capacitors on both panel board sides (left and right) have shorts in between their contacts and that does not seem right to me. They are marked red in the panel board picture.

What I dont know is if the SMD capacitors are the reason for it. I dont see any other causes on the panel board and visual inspection is fine.

[dick_barton]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Just measure the resistance across any one of the capacitors on the left hand side and then again on the right hand side of the board and give their resistance readings. With the ribbons disconnected from the connectors and of course test with the set switched off.

As shown in the photo
Left-hand side capacitor reading =
Right-hand side capacitor reading =

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

The potentially failing capacitor(s) are "CHxx" and on the left panel board side and also "CO".

I think I found the failing capacitor on the left panel board side (CO). Resistance is around 2-3 Ohm there and 5-8 Ohm on the other CHxx capacitors.

On the right panel board side I have values around 10 Ohm at all CHxx capacitors. Impossible to determine which one has failed.

[dick_barton]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Can you unsolder one at a time and check them?

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Can you unsolder one at a time and check them?

I dont have SMD equipment (heatgun is not an option due to the plastic connectors and ribbons).

I was thinking about destroying them one by one using a dremel, to see if that solves my issue.

Shouldnt it work without the capacitors anyway.

[dskall]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Can desolder with soldering iron. Manufactures don't tend to add unnecessary parts

[dick_barton]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

+1
Soldering iron is all that's needed and a pair of tweezers would be helpful so as not to lose it.

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

I removed the suspicious capacitor on the left panel side. Still a short somewhere....

... and worst of all I measure now shorts on CAxx capacitors as well. What is on the other side of the plastic ribbon?

You were right, it worked well without SMD tools. I used to work with SMD tongs at work, but currently I only have access to my small laboratory at home.

[dick_barton]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Is the short on those capacitors still there with everything disconnected from the Tcon?

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

yes, nothing from the tcon is connected.

[dick_barton]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

You may have a short circuit IC on the board. One way to find out is, if you have a separate power supply which you can power only the tcon with beginning from 0V and raise the voltage slowly keeping an eye on the current. The defective component is likely to get very hot very quickly.
No other connections attached to the tcon.

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

the failure is not on the tcon board it is on the panel board.

I dont see any ICs there. Only discrete components (capacitors and resistors).

[dick_barton]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Sorry but I was looking at the second photo. If you have checked all the capacitors then it looks as though you may well have a panel fault. Wait and see what others have to say.

[budm]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

the failure is not on the tcon board it is on the panel board.

I dont see any ICs there. Only discrete components (capacitors and resistors).

The LCD panel does have TFT driver ICs on the flexible PCB between the tab bonding board (and also on the side of the LCD panel) and the LCD glass panel.

[dskall]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Might try powering it up and see what is getting hot.

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

Might try powering it up and see what is getting hot.

I trink the TCON disables Power Suppen to the panel Bord.

[mirokulaz]

Re: Samsung UE/UN55ES6xxx - black screen with backlight on.

The LCD panel does have TFT driver ICs on the flexible PCB between the tab bonding board (and also on the side of the LCD panel) and the LCD glass panel.

If the defect is there I have no chance to repair, right?