samsung LM46c630

[pete78]

Hello I have a Samsung TV and the screen went black but I have sound but no picture I've searched in the search and only found 3 posts about this prob can somebody help me thank you I was told its ether the backlight inverter or the power supply

[tom66]

Re: samsung LM46c630

Pictures of the board? BN44-xxxxx number on power board?

[pete78]

Re: samsung LM46c630

Board number is BN4400341 my cam had died ill upload pics in a bit

[tom66]

Re: samsung LM46c630

Schematic
http://www.tgohome.com/ServiceManual...&Search=Submit

When you post pics, we can highlight where to make checks.

[pete78]

Re: samsung LM46c630

Thanks ill be home in a while and ill upload those pictures

[pete78]

Re: samsung LM46c630

Ok here they are sorry it took so long to upload

[pete78]

Re: samsung LM46c630

Bump

[tom66]

Re: samsung LM46c630

Just realised this might be the set with a jumper marked JP852 on the power board, do you see that? If so cut this jumper, it disables a low-voltage cut out which was set incorrectly by Samsung and causes problems later on.

[pete78]

Re: samsung LM46c630

That didn't work do I leave it cut?

[pete78]

Re: samsung LM46c630

Anyone else have a idea?

[tom66]

Re: samsung LM46c630

You can leave it cut for now. Now, unplug the connector running between the main board and power board, the backlight of the LCD should come on, does it? The main board has the video inputs on it.

[pete78]

Re: samsung LM46c630

Nope the red light for the power button won't come on when I do that

[truep]

Re: samsung LM46c630

Don't worry about the LED, We are just looking to see if the backlight came on. If not, It's either the power or Balancer board. (the one on the side). The inverter on the power board is probably the problem. Is there even a quick flash of backlight? If you shine a flashlight on the screeb can you see a picture? It can be hard to see and you may have to shine at an angle.

[pete78]

Re: samsung LM46c630

Still no backlight and yes I can see the picture with my mag light

[budm]

Re: samsung LM46c630

OK, this power supply-inverter board has built-in pullup resistors, so if you disconnect the cable between the power supply and the main board, when you plug the TV into the outlet, the backlights should come on and stay on right away to indicate that the board is OK.

[pete78]

Re: samsung LM46c630

I'll test it when I get home and thank you guys for helping me with this problem

[pete78]

Re: samsung LM46c630

OK did that and still no back lights but in a dark room when I turn my TV on it starts to light up but quickly goes out sorry I took so long to post back

[tom66]

Re: samsung LM46c630

So if you look from the rear of the set, you can see a brief white light through the holes in the metal plating?

[pete78]

Re: samsung LM46c630

Sorry I meant from looking at the screen

[truep]

Re: samsung LM46c630

Could we get a closeup of the label next to the connector at the bottom left of your picture of the Power supply. I believe that cable goes over to the balance board.