Re: Dell SE198WFPf - Backlights go off after 2 seconds



Hi PlainBill, thanks. You are right. The ccfls are still ok to work after testing by hooking them to another inverter, which can fully light them up. It appears that the old one cannot produce the voltage high enough. So do I need to upgrade the capacitor values? Like replacing 3 black 470uF ones to 820uF ? As it is the closest value that I have. Any suggestion, thanks....

Re: SyncMaster 740N strange lines



Check out the panel serial no. if it looks like AUxxxxxxx, or LG Samsung made. Mostly, the signal controller chip on the panel has burnt inside. I had the same experience before, by replacing another compatible panel, then it back to normal....

Re: Dell SE198WFPf - Backlights go off after 2 seconds



Hi PlainBill, thanks for the reply.

I have taken the bottom ccfl out of the LCD panel, and tested these two tubes individually by a tester instead of the monitor's inverter. It can light up but begin to get red/pink, and part of the tube is dim. And when saw closely, found two ends have been burnt to black. No wonder the light spread unevenly on the screen in previous test. Right now, I'm pretty sure the ccfl is the culprit. But here comes to another question: Where can I get the right size CCFL? ...

Re: Dell SE198WFPf - Backlights go off after 2 seconds

I got the same model(SE198WFPf) Dell monitor and it has the same problem. The date of mfg is May 2008.
But it looks weird.
a) When set the brightness and the contrast to 50%, the backlight turns off after 1 or 2 seconds, but the power LED stays on, and u can see the shadow of the image.
b) When set the brightness and the contrast to 100%, it can stay longer (about 30 minutes), then the backlight turns off.
And have checked the power board and logic board, no sign of burn or bad-solder. Also checked...

Re: Problems with Samsung 740N monitors

Tanks for all the guys here. I got really helpful info here during the DIY for repairing my Samsung 740B.
Right now, I got my LCD work and go well.
What I did is:
a) replaced three 820uf 25v caps beside the transformer
b) unsoldered the green small 3A fuse beside a 820uf 25v cap, then solder a solid wire into it.(as i don't have any alternation one in hand, but it is risky)

As a result, bad caps always play the key role and induce the fuse burnt.
New discovery: OEM used the same model power...