Dell E1909W - No Power and LED Off

Service Manual
30
Chapter 6- TROUBLE SHOOTING
Common Acknowledge
 If you change the M/B, be sure that the U103,U201 and U108 these three components also changed to
the new M/B because there was program inside. If not, please re-write EDID or upload firmware into
serial flash(U108). How to do please refer to the Page 19.
 If you adjust clock and phase, please do it at condition of Windows shut down pattern.
 Please confirm the R/G/B color under 32gray scale pattern.
 This LCM is analog interface. So if the entire screen is an abnormal color that means the problem
happen in the analog circuit part, if only some scale appears abnormal color that stand the problem
happen in the digital circuit part.
 If you check the H/V position, please use the crosshatch pattern.
 This LCM support 10 timing modes, if the input timing mode is out of specification, “Cannot Display
this Video Mode” will be displayed on the screen.
 If brightness uneven, repairs Inverter circuit or change a new panel.
 If you find the vertical line or horizontal line lost on the screen, please change panel.
 If the self-test pattern is moving on the screen, please check whether VGA Cable is plugged in the
Monitor or PC if select analog model on OSD or check whether DVI Cable is plugged in the Monitor
or PC if select DVI model on OSD . If the VGA or DVI Cable is plugged in well, please change
another VGA or DVI cable.
No Power and LED Off
Is there DC24V at C863;
Is there DC5V at L854;
Is the voltage at C854 in the
range of 127V~339V?
Is the voltage at pin7 of U850 18V?
Is the voltage at pin6 of U850 0.9V?
Is the voltage at pin8&pin9 of T850 38V?
Check Q850
Check RT850, F850
Check R862
Check D852
NO
YES
YES
YES
YES
NO
NO
NO