samsung-la40b5501rsxo

[WILLYAM1]

hi.
backlight is flashing for a 1 minute and then its ok.
all valltge ok  no bulging capi.
p.s/inv BN44-0264.all primery resi in inv trans a few ohms and the secondery is about 1.015k.
seems to me the problems is ccfl but if so the protected circet sould activated and shut the screen?.
is ther any trick to check the ccfl without dismentel the screen?.
willyam

[Keith]

Hi

Check the ESR of the capacitors on the inverter supply first.

But could be a CCFL tube. If you run it with the LCD panel open you may see one or more CCFL tubes failing to strike.

Keith

[WILLYAM1]

thanks .
all capi esr ok.
I will open it today and see the condition of the ccfl.
willyam

[Icantthink]

Hi

Dont know if it will help

Is there a DP805 on the board should be marked 0907 ,0908, 0909...check that diode,  Samsung had a problem with these on the 262a for the 37inch that gave backlight problems.

Also is there ZD803/ZD804 on the board,  two zener's at the edge of the board just behind the long heat sinks..if so check them