CONFIDENTIAL
Service & Analysis Center Europe
Training Team
version 1.0 / 05.11.1999 Page 23 of 37
Display failures
Black lines on the display or no display function
•
Check if the display have some mechanical breaks around the corners
•
Check VBB 2,8V DC on C400 and R420
•
Change the Display
Display failure
missing line
segments or no
display function
check the LCD_LED line
pin 9 N400 to V406,
V409, V412, V413
"
on"=1,2V DC/
"off"=1,9V DC
check the display
of mechanical
appearance
Check VBB 2,8V
DC on C400 and
R420
no display back
light
check VDC_OUT
3,2VDC on V406,
V409, V412, V413
change the
display
Yes
oK
Yes
oK
If no VDC_Out
voltage PCB will
be brocken
not oK
not ok
check the VBB
voltage on V117
not oK
swap the
handset
because the
PCB is faulty
oK
oK
check pin 1 N400
VDC_OUT, pin 2
VBB, LCD_LIGHT
pin 7 "on"=2,8V,
R415 12K Ohm pin 8
to ground
faulty