samsung ln46b550 backlight on off

[freakaftr8]

So I picked up this TV and after about 40 minutes the back lights start turning on and off with in intervals of 5 seconds. After the 4th or 5th flash eventually the back lights will stay off until you re power of the TV. I've checked transformers resoldered connections and I have found that when you apply heat to an area in the center of the board with the small switching transformer the back lights will go out and stay out indefinitely and if you freeze it it'll come back on. Has anyone had any issues with this style power supply before doing this?

Power supply model BN44-00265B

[budm]

Re: samsung ln46b550 backlight on off

Check the DCV between the two legs of the main filter cap.
You may want to read this also.
https://www.badcaps.net/forum/showth...ht=BN44-00265B

[freakaftr8]

Re: samsung ln46b550 backlight on off

Yeah I looked into it looks like the 684k 500 volt capacitance raises under heat. Replaced it with a mylar film type 600v 684j for good measure. So far working fine.

Some kind of control circuit for the backlight system. Don't have a schematic on thus power supply.

[freakaftr8]

Re: samsung ln46b550 backlight on off

Actually looks like I got it repaired. Bad cold solder joint somewhere on the underside of the board near the output transformers and all the small SMD area. I resoldered all three pin transistors underneath the board and that seems like it repaired it