Samsung LN32B360C5D picture on / off

[krygods]

I have here a Samsung LN32B360C5D that powers on, picture comes on and goes off 4 times and then stays off. TV is still powered on after the picture goes out after the fourth time. Pressing the power button turns the TV off.

Any thoughts?

[niblettr]

Re: Samsung LN32B360C5D picture on / off

Is the picture still on the screen (when screen appears to be off even though TV is still powered on and you say) Use a flashlight close up to the screen to see if you see faint picture.

[krygods]

Re: Samsung LN32B360C5D picture on / off

Yes indeed I can faintly seen an unlit picture when I look very closely with a bright flashlight.

[niblettr]

Re: Samsung LN32B360C5D picture on / off

Ok, problem has been narrowed down to backlight generator or power feeding it. Unfortunately, I have never worked on an LCD tv so someone else more knowledgeable should come along and take over from where I left.
In the mean time (this is guess work) locate power cable going to backlight, disconnect and inspect connections. check for brackening crimps. Also check that crimps mate with connector nice and tight.

[niblettr]

Re: Samsung LN32B360C5D picture on / off

https://www.badcaps.net/forum/showthread.php?t=25196

[krygods]

Re: Samsung LN32B360C5D picture on / off

Just finished checking all the diodes on the power supply, all test ok.

[krygods]

Re: Samsung LN32B360C5D picture on / off

Does anyone know where the backlight is on this tv? i don't even see a connector that would go to the backlight.

[budm]

Re: Samsung LN32B360C5D picture on / off

The Lamps are in the sockets, and the sockets are connected to the inverter board through the fingers of the board.
So it can be bad connections on the lamp socket, BTW, do not try to remove the scokets or you will break the lamps.
http://www.shopjimmy.com/catalogsear...ng+LN32B360C5D

[krygods]

Re: Samsung LN32B360C5D picture on / off

so everything to do with powering the backlight is on the power / inverter board in this model? what are the components that I would need to check to troubleshoot this issue?

[CapLeaker]

Re: Samsung LN32B360C5D picture on / off

http://www.shopjimmy.com/samsung-bn4...er-supply.htm#

[budm]

Re: Samsung LN32B360C5D picture on / off

What the model number of your board? There are more than one version used in your model, see the link I gave you to SJ.
You should verify that the DCV between the two legs of the main filter cap is at >360vdc, check the resistance of the inverter transformer winding resistance to see if they are within 3% form each other, etc.

[krygods]

Re: Samsung LN32B360C5D picture on / off

Main filter cap is at 160VDC off and 380VDC on.

I took some pics of the top and bottom of the power/inverter board.

As for the inverter transformer, which transformer is it? is it the two identical ones near the fingers for the backlight?

Also I'm not familiar as to how to test the windings so if someone can guide me through that I'd be ever so thankful.

[budm]

Re: Samsung LN32B360C5D picture on / off

But which board do you have?

[krygods]

Re: Samsung LN32B360C5D picture on / off

I have the BN44-00289A

http://www.shopjimmy.com/samsung-bn4...wer-supply.htm

[budm]

Re: Samsung LN32B360C5D picture on / off

Look at the bottom side of the board, you can see there are two pins in the primary side of the inveter transformer, then to top row of the transformer has 4 pins for the seondary windings (two windings for secondary), two pins to the left is for one set of winding, two pins to the right is for the second set of winding.

[krygods]

Re: Samsung LN32B360C5D picture on / off

here are the resistance checks on the secondaries

TI802
1069
1065

TI801
1041
1132

[budm]

Re: Samsung LN32B360C5D picture on / off

1132 does not look right. You should take that transformer out and look at the bottom side of the tranaformer.
What are the P/N as printed on the transformer?
Like this?
http://www.shopjimmy.com/qgah02107-i...ransformer.htm

[krygods]

Re: Samsung LN32B360C5D picture on / off

Transformer P/N
QGAH02107
NVB-003

I'll go ahead and desolder the transformer right now

[CapLeaker]

Re: Samsung LN32B360C5D picture on / off

Ti801 is well over 3%.

[budm]

Re: Samsung LN32B360C5D picture on / off

If Shopjimmy sells them, it means it is one of common failure parts, I would replace both of them at the same time.
If the winding has sign of over heat, that can be due to worn out lamp that is drawing too much current from the transformer.