Dell E190Sf, Service Manual

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Service Manual
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new M/B because there was program inside. If not, please re-write EDID or upload firmware into
serial flash(U402) via VGA Cable. How to do please refer to the Page 19.
z If you adjust clock and phase, please do it at condition of Windows shut down pattern.
z Please confirm the R/G/B color under 32gray scale pattern.
z 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.
z If you check the H/V position, please use the crosshatch pattern.
z
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.
z
If brightness uneven, repairs Inverter circuit or change a new panel.
z If you find the vertical line or horizontal line lost on the screen, please change panel.
z If the self-test pattern is moving on the screen, please check whether VGA Cable is plugged in the
Monitor or PC. If the VGA Cable is plugged in well, please change another VGA cable.
2. No power supply
Is there DC1 2 at L852;
Is there DC 5V at L851;
Is the voltage at C854 in the
range of 127V~372V?
Is the voltage at pin8 of U850 354V?
Is the voltage at pin3 of T850 510?
Check D850, F850
NO
YES NO
NO
Check R853
Is the voltage at pin6 of U850 18.0?
NO
Check D852 ,R856
YES
YES
Check Q850 ,U850
YES
Check D854;
Check D856/D857;
YES