Samsung LED 3d TV won't turn on

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Old 07-08-13, 06:51 PM
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Samsung LED 3d TV won't turn on

My Samsung UN46C7000 LED 3d TV stopped working last night. I was watching a movie when the sound started breaking up and then the screen went black. I turned off the TV, then tried to turn it on and nothing happened (no backlight either as far as I can tell). I have tried unplugging it an plugging it back in after 30 min. I also left it unplugged overnight just to be sure.
The TV clicks once when it is plugged in and the red light blinks for about 10 seconds then turns off. If I press the power button, the buttons light up but that is all. If I use the remote, the red light blinks quickly as long as I am pressing the buttons. Does anyone have any ideas what could be wrong?
I am pretty good with multimeter and basic electronics. I would like to try and fix this problem myself. If anyone can offer assistance on where to start I would appreciate it.
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Old 07-14-13, 06:35 PM
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Update

I took the back cover off. There are 3 boards visible. One board that converts AC to whatever voltages the TV needs, an audio video board that has all the jacks and ports on it and a 3rd board that is connected to the AV board. I don't know what that one does.

The power board seems fine. I checked the fuses, the capacitors look good and The voltage outputs look good. I only checked the easy to reach ones (1-17 odd). I tried unplugging the connector to test the others but the power went dead when I did that. There is another label that says that 12V should measure 12.8V and V[SUB]AMP[/SUB] should read 17.5.

Pin Label Measured Voltage to ground
1 - 12V 12.82 V
3 - 12V 12.82V
5 - 12V 12.88 V
7 - GND -
9 - GND -
11 - 5.3 V 5.28 V
13 - 5.3 V 5.28 V
15 - V[SUB]AMP[/SUB] 18.8 Are these too high?
17 - V[SUB]AMP[/SUB] 18.8

Pins 2- 18 Labels
2 - OD ON
4 - BL ON
6 - T-DIM
8 - B-DIM
10 - GND
12 - GND
14 - 5.3
16 - STBY
18 - PS-ON

Does this board check out? Is there anything else I can check on the board? How do I check the other boards? Anyone have any advice?
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Old 07-14-13, 07:27 PM
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Welcome to the forums.

Without a schematic it's virtually impossible to fix it.
The 12v and 5v supplies are working.

The link is a place where you can buy the service manual. Don't bother searching for a free download as you won't find it.

Service Manual _UN46C7000WF, UN46C7000WF-NO SCHEMATIC, UN46C7000WM, UN46C7000WR, UN46C7000WR-NO SCHEMATIC
 
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Old 08-08-13, 12:16 AM
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As somebody stated, you really need the schematic diagram to repair this. It is NOT a basic multimeter check.

Power supplies these days are not simply 'voltage providers', but also have digital lines in them. As an example... is there a 'reset' circuitry (just like PC power supplies?). Without that reset, the TV will never start. In older tube VGA monitors (which is actually what modern tvs are), a 33k startup-resistor used to be imperative to start driving the circuitry...

I have a Samsung 50 inch myself. When I switch it on, the onboard RELAY clicks... are you getting this?
 
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Old 08-08-13, 05:34 AM
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I'm surprised I missed this thread...
$10 says its a capacitor or two on the main power board.
I had to replace 2 on my own LG plasma about 9 months ago and done probably a dozen other TVs (various brands) since. 90% of the time, it's capacitors on the main power board. Of all the TVs I fixed or looked at, none of the flat panel TVs had fuses inside. They are not meant to be a quick fix for say.

DO NOT work on the TV with the power connected. Disconnect, and hold in the power button for a couple seconds. Let stand for 10-15minutes.
When searching out for bad caps, focus on the larger (non-technical term here) tube/cylinder type caps. You are looking at swelling on the top (rounded top), discoloration on top (leaking) or any that are leaning (swelling at the bottom, pushing out the plug).
Take your time and use a flashlight. Shine the light at different angles as these can be hard to spot.
Here are a couple photos of what mine LG blown caps looked like. Repair cost was under $5 (had to order the caps as I didn't have any handy).
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Old 10-10-14, 12:54 PM
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Hi, I have the same TV and it stopped working since last night. I am curious what you ended up doing to get this thing working? Any helping hand is appreciated.
 
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Old 10-10-14, 05:53 PM
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Welcome to the forums.

The original poster hasn't been back since he posted his problem. Northern Mike posted about checking capacitors visually on the main power supply board. You can start there. Otherwise there are many different things that can cause a TV to not turn on and like I posted.... without test equipment and a service manual it may not be an easy repair.

I was checking at some of the Samsung forums..... capacitors were the only listed problem with this tv. Several people posted about getting help right from Samsung... like extended warranty. Some of the people were successful that route.
 

Last edited by PJmax; 10-10-14 at 06:39 PM. Reason: added info
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