Chosen Solution
I have a 2009 Samsung LCD-LED TV. Model No. is LN52B550K1F, model code is LN52B550K1FXZA. The power LED flash 5 times when I plug in the power cord. The starting sound is normal. When I plug my laptop HDMI output in HDMI IN 4 port, I have sound and I can see a faint picture with flashlight. The backlight is not working. I tested the two power cord from power board to BLU and there is 0 voltage. (in the red circle in the picture) I pluged the BLU power from another working LN40A500T1F TV to this one and the backlight flashed before down.How can I fix the backlight?
@henry21347 by your connectors, your TV has CCFL backlight. Since you have no power on those. (not sure how you tested it since those are HV lines) it could be the main board not telling the power board to turn the BL on. Disconnect the power board form the main board and see if the backlight comes on. If it does, you know the issue is your main board or your T-con board. If the backlight does not come on, it could be your power board. Next you would check to see if you have power on the BL-En on your connector. That is the power to enable the backlight by the power board. If you have that then it is most likely the t-con board. Check the fuse on the t-con board for continuity and voltage. You should get ~12V on that.
