Samsung UN48H6350AF Black Screen w/ sound

[nomoresonys]

Re: Samsung UN48H6350AF Black Screen w/ sound

If you can, try tracing bl-on line back to that L204 area.

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

Here's a shot of that area of the board. I tested the component at the area labeled IC204

[William1967]

Re: Samsung UN48H6350AF Black Screen w/ sound

Disconnect the FCC cables between the t-con and the display. Than the backlight must come up. These H-series of Samsung have a lot of problems with the display. When lucky only a small SMD capacitor has a short circuit, if unlucky one of the COF's has a short circuit. Keep in mind that the T-con has 3 blue leds and all 3 must light up when the tv is working, not just one.

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

So are you suggesting looking for a shorted smd capacitor on the T-con board?

I'll verify the number of blue led's on the T-con board as well.

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

The first picture is when both fcc cables are connected to the display from the T-con, with just 1 blue led on and backlights off. Upon power up two leds come on briefly, but then only one stays on continuously.

The next picture is with both fcc cables disconnected, two leds come on and stay on.

If there is a third led that is supposed to come on, I dont see it on the board, but I could be wrong.......

any suggestions now?

[budm]

Re: Samsung UN48H6350AF Black Screen w/ sound

"The next picture is with both fcc cables disconnected, two leds come on and stay on. "
But the backlights still do not come on when both FCC cables are disconnected, right?

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

Sorry, I did not state that in the last post the backlights DO come on when both FCC cables are disconnected

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

Maybe this will help....short video

https://youtu.be/yw2eCzwZd0g

[budm]

Re: Samsung UN48H6350AF Black Screen w/ sound

OK, then you may have problem with the COF or caps on the tab bonding board like William1967 has suggested.

[nomoresonys]

Re: Samsung UN48H6350AF Black Screen w/ sound

You could strip it down a little and check the driver board/tab bonding board, usually if a cof is bad it will get hotter than the others or be blacker or burnt looking, cof is chip on film and is on the flex connecting driver board to panel but usually when faulty you get a least something on display like vertical lines etc. still seems like a mainboard issue.

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

Do you think there is a way to track down what component on the mainboard is causing the issue?

[mlemon]

Re: Samsung UN48H6350AF Black Screen w/ sound

Looks its been years now for this thread/issue. I wonder what the fix was here? Thanks

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

I did not find any fix for this, I think I replaced the main board and the problem persisted. Ended up recycling the panel.

[neilc6]

Re: Samsung UN48H6350AF Black Screen w/ sound

If you can get video on one half of the screen, you can try the tape cutoff method. If TV turns on with no video and no backlight but the backlight works with main cable unplugged, you can try replacing the tcon board.

[mlemon]

Re: Samsung UN48H6350AF Black Screen w/ sound

I did not find any fix for this, I think I replaced the main board and the problem persisted. Ended up recycling the panel.

Wonder if you still have one good main logic board! I am in need of one for same Samsung model 48" TV? Plz let me know. Thanks

[mlemon]

Re: Samsung UN48H6350AF Black Screen w/ sound

The first picture is when both fcc cables are connected to the display from the T-con, with just 1 blue led on and backlights off. Upon power up two leds come on briefly, but then only one stays on continuously.

The next picture is with both fcc cables disconnected, two leds come on and stay on.

If there is a third led that is supposed to come on, I dont see it on the board, but I could be wrong.......

any suggestions now?

FYI - I know it's way too late and newly joined this forum but I thought I point out the LED3 location for kicks

[mlemon]

Re: Samsung UN48H6350AF Black Screen w/ sound

I thought continue this thread since I have same exact tv brand and model but the behavior slightly different.

Issue with my TV is:

1. The standby red LED continuously flashing red with dark screen. Pressing the power button manually or from the remote has no effect
2. When and if all the cables are connected, the display is dark, nothing appears on the screen.
3. The flash light test of the LCD display does not produce any images that is because there is no power reaching the LCD from the Tcon board.
4. The Tcon board gets no power at all on pins 47 to 51 (according to the legend) of flex cable from the MB, expected 12 to 13V. The fuse on the Tcon is NOT open, I verified. And there are 3 LEDs on the Tcon board, none is lit, supposedly blue. Again, the Tcon board does not get power from the MB board therefore, I do not expect these blue LEDs to light up.
5. The Main logic board gets the 13VDC from the PS. I am very confident the PS has no issue given I verified all the voltages with and without load (cable to backlight LEDs and cable to to MB).
6. If I disconnect the flex cable from MB to the Tcon board, the backlight LEDs start flickering at the same frequency as the flashing red light, appears that way anyway.
7. If I disconnect the power cable from PS to the MB, the backlight LEDs will light up and say lit with Blue screen while the standby red light still flashing
8. Disconnecting the speaker and power board/IR board from the PS has no effect.
9. Here are the voltage readings on the PS plug to the MB:

Again, pressing power button has no effect but the PS to MB makes a bit of a difference on some readings, the Even pins [2,4,6]:

Connector CNM803 - PS <---> MB. All measured Voltages:

(Even Pin#)

All Cables connected PS <---> MB Disconnected

2 OD/UD 0.1 - 2.47V 2.29V
4 BLU ON/OFF 0.0 - 0.15V 3.3V
6 PS ON/OFF 0.0 - 3.30V 4.46V
8 GND 0.0 0.0
10 GND 0.0 0.0

(Odd Pin#) - same values when all cables connected and disconnected.

1 A13V 12.12 - 12.77V
3 A13V 12.1 - 12.77V
5 A13 12.1 - 12.72
7 A13V 12.1 - 12.72
9 GND 0V

My observation is that the CP or BGA on the MB keeps resetting probably on Pin 6 (PS ON/OFF). I did back trace pin 6 and 4 with some measurements on the MB but could not find anything shorted or open, at least nothing obvious. And nothing charred or burnt on any of the boards.
Also, I heated the BGA with hot air gun for 3min and did not make any difference.

All indications point to the MB but I am more interested in figuring out which component (s) is faulty. Replacing a whole board takes the fun out of it and frankly not worth the cost given how expensive they are. So any help or pointers much appreciated. Thanks

[mlemon]

Re: Samsung UN48H6350AF Black Screen w/ sound

Here is the CNM803 connector image

[mlemon]

Re: Samsung UN48H6350AF Black Screen w/ sound

Sorry guys. I have created a new thread to my TV issue. Sorry about this confusion, a newbie mistake

Link to new thread:
https://www.badcaps.net/forum/showthread.php?t=95560

[handsworth]

Re: Samsung UN48H6350AF Black Screen w/ sound

I just picked up a UN55H6350 with the same problem. I thought it was the main board because the blue lights on the T con were lit. Disconnected the tcon tabs one at a time and supplied power. Same results, no pic but sound and backlights. Replaced tcon with one off the shelf and picture came in. Just an idea.