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Samsung PN50B860 - No picture from any sources. Any known solution?

post #1 of 24
9/17/12 at 7:25pm
Thread Starter 
The TV had been serving me well until this afternoon while watching CBS the screen went off. I could still hear the audio on my receiver. Power cycle didn't help.

Unplugged it for couple of hours but it still showed nothing. Not even the source information that pops up when changing sources or channels. But the TV responds to remote when I try to change the channels, power it on, change sources etc I can hear the audio changing.

I have left it unplugged to see if it somehow works tomorrow but unlikely. Any one experienced this before? It's 3 years old and out of warranty but expected a $2k TV to last a bit longer. It did have a few minor issues like suddenly the IR receiver would start acting up or the channels would change automatically but power cycling would fix those usually, not this time.

Any comments / suggestions appreciated.
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post #2 of 24
9/18/12 at 3:53pm
Thread Starter 
Noticed something today which might mean something - there was a green LED flashing at the back of the TV set when I powered it on.

Does this give a clue? Google thinks blown capacitors.
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post #3 of 24
9/19/12 at 7:09pm
Thread Starter 
I removed the back today and the flashing LED is marked LED2000 (near bottom-center).

There is another LED, LED5001, on the left side and it glows steady. Here is a picture showing the LEDs - anyone knows which PCB is for what (display, audio etc)? Thanks.


v3kayf.jpg
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post #4 of 24
9/20/12 at 4:59pm
Thread Starter 
Mainboard power connector area -

27zx0ut.jpg


Controller board with the pin 3 - 4 jumped with blue jumper

xqhvev.jpg
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post #5 of 24
9/20/12 at 5:21pm
Thread Starter 
Here is another showing the pins jumped

2la349u.jpg
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post #6 of 24
9/20/12 at 5:38pm
Pins 1 & 3 on the Power supply were wrong (no harm done). I will find a schematic and get the proper pin numbers.
Aside from that, I am pretty sure we need to see two LED's on the control board. (one flashing about once per second and a steady LED)
I will confirm.
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post #7 of 24
9/21/12 at 4:45am
Thread Starter 
Thanks Earl, really appreciate the help. I'll look for the 2nd LED and update.
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post #8 of 24
9/21/12 at 1:05pm
Thread Starter 
Found the 2nd LED (LED2001). It's OFF even when the TV is ON and LED2000 is flashing

2vaxi8g.jpg
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post #9 of 24
9/21/12 at 1:34pm
Ok good. After some review, that is normal operation.
Reconnect everything as it was when you removed the cover. Watch the screen as you power it on and see if the screen ever flashes even slightly.
Also, check for an LED on the X-Main (Board on the right when looking at the back).
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post #10 of 24
9/21/12 at 3:05pm
Thread Starter 
I did not notice any flashing on the screen at all. Tried with closed blinds as well.

I located another LED4401 on the board above the mainboard.

35aoitv.jpg
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post #11 of 24
9/21/12 at 5:15pm
That is the X-Board. Does that LED light up when the set is on?
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post #12 of 24
9/21/12 at 5:48pm
Thread Starter 
No, LED4401 stays off all the time.

Just noticed LED2001 flashes couple of times when I turn the set on with the remote, then goes off and stays off.
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post #13 of 24
9/21/12 at 6:12pm
Ok. That may very well be the problem board (X - Main). Find VS on the Y-Main and X-Main. I will get back with more test points.
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post #14 of 24
9/21/12 at 7:18pm
Thread Starter 
Sorry, what is VS

Edit: Is this the one? Both VS1 and VS2 have 208.5V

2ppc55h.jpg
Edited by rexian96 - 9/21/12 at 7:59pm
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post #15 of 24
9/22/12 at 5:42am
Yes, that's one of them (VS). I assume that is the X-Main in the picture. The Y-Main also uses VS.
Check both of those fuses on the X-Main. That adjustment screw in the pic has a test point somewhere on the board labeled V-Bias or something similar.
You need to find a place to measure that voltage. Can You post a picture of the entire X-Main and Y-Main?
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post #16 of 24
9/22/12 at 7:05am
Thread Starter 
Here is the full X-Main. I see just one fuse there. The fuse is good, shows 208.3V on both sides.

ou9j6q.jpg
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post #17 of 24
9/22/12 at 7:19am
Thread Starter 
This is probably Y-Main. The fuse is good, has 208.3V on both sides. Same with VS1 and VS2, both 208.3V. I'll look for V-Bias.

11udjep.jpg
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post #18 of 24
9/22/12 at 7:47am
Thread Starter 
Could this be V-Bias? It shows 95V.

ifa3v5.jpg
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post #19 of 24
9/22/12 at 8:49am
Thread Starter 
Also checked V-Scan on the Y-board in case it matters. -173V

14j91uh.jpg
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post #20 of 24
9/24/12 at 5:06am
Those key voltages all seem to be correct. There is another voltage I would check. On some panels it is called VDA. You should be able to find it at the bottom connector of the X-Main. This voltage should be around 60-75 volts DC.
Also, That little green 'tic-tac' looking component (near CN4001 on the X-Main) above the large white fuse is also a fuse (F4001). There is also one on the Y-Main. Check all of those as well and any others labeled Fxxxx. There is also a fuse (white with copper ends) under the control board connector. Look for and check those as well.
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post #21 of 24
9/24/12 at 3:53pm
Thread Starter 
Sorry, couldn't locate VDA. Would that be near CN4001 (top of X-Main) or CN4700 (bottom of X-Main)? I checked Vcc on the CN4001 and it's around 15V.

All the Fuses seem to be alright. I checked 2 on X-Main, 2 on Y-Main, 3 on power board and 1 (white) on control board.
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post #22 of 24
9/26/12 at 3:23pm
Thread Starter 
Here are the jumps -

29f9k04.jpgrjejco.jpg
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post #23 of 24
9/26/12 at 6:40pm
Thread Starter 
aeqlmo.jpg

2j2w9l0.jpg
284axk.jpg
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post #24 of 24
10/4/12 at 11:05am
My PN50B860 just went out last night with exact same issue -- no pic on any source. It first started with HDMI, so I went to the component and now it's just a 50" mirror !!!!

Have you been able to ID the root problem ? Is it worth fixing ?
You've done some deep troubleshooting -- not sure a local TV repair shop would be as exhaustive.

Any insight would be appreciated -- thank you !
Ev
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