Dell SE198WFPt 2 Seconds to Black

[fuzzyspudkiss]

Hi Guys,

I have read over the other posts on this site involving similar monitors and I cant seem to troubleshoot the issue on this one. It powers on, shows the dell testing screen for two seconds, then powers off.

What I have done:

• Checked caps for leakage
• Pulled CCFLs and checked for burns/breaks, I didn't check the solder next to the lamp but they both seem to be turning on(if you have any suggestions on how to test the CCFLs futher please dont hesitate to tell me)
• Tested the transformers (I can provide info on specific Ohms if you want but they were both exactly the same)
• Did an overall visual check of the inverter/power supply board

I am posting some pictures of the front and back of the board, as well as two spots that I found that looked a little out of the ordinary. I wasn't sure if the two spots I posted would be causing any issues or it was just cosmetic.

Thanks again guys

[fuzzyspudkiss]

Re: Dell SE198WFPt 2 Seconds to Black

UPDATE:

I tested the Transistors and one of them ( D856, I attached a pic) has no resistance (.2 Ohms) between the two leads I pointed to. Could this be the part of or all of the problem?

Disregard this update, found out its a diode and not a transistor. Pins 1 & 3 are aparently supposed to be wired together.

http://www.datasheetarchive.com/SRF10-10-datasheet.html

[Rtech]

Re: Dell SE198WFPt 2 Seconds to Black

I assume that you did have an input signal from a PC going into the Monitor,otherwise it will switch off after a short time ????? I find the best way to test CCFLs is by substitution one pair at a time,and that will determine if one or more is faulty,and also may identify if the problem is in the top inverter/tranformer circuitry or the bottom.As the circuitry for top and bottom inverter circuits are very similar, you should compare and measure eg R20 and R21, other resistors,and look closely at the Blue caps in there.

[ben7]

Re: Dell SE198WFPt 2 Seconds to Black

Test the voltage going to the backlight inverter on the PSU board. If the voltage doesn't sag much, then you might have a bad ccfl.