Samsung SGH-X640 Service Manual page 38

Flow Chart of Troubleshooting
9. LCD Part
LCD does not work
Yes
No
Is LCD Contrast set on high
Set LCD Contrast on high level
level in the Menu?
Yes
No
Check the R304, C308
HDC700 pin 24 = 2.8V?
Yes
No
HDC700 pin 19(L_WR),
Check the U303
20(RS) is OK?
Yes
Replace the LCD Module
Yes
END
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