RM-12
Nokia Customer Care
Issue 1 11/2004
COMPANY CONFIDENTIAL
61
Copyright © 2004 Nokia. All Rights Reserved.
Blank Display (1)
Inspect EMI
components
Z4421-Z4423 and
display clock
filtering capacitor
C4444 for poor
soldering.
Check for bad
connections/
broken
connector.
Fault in
connectors
Connections
OK
Yes
Clean/replace
connector from
phone.
Working?
Try with
another display
module. Display
working?
Yes
No
12.5MHz clock detected
Measure V28
from L4427.
Voltage OK?
Measure
display clock
from C4444.
No clock
No
End
Yes
Go to Power
troubleshooting
No
Check
C4439-C4440,
L4427
components
OK?
No
Yes
Replace
broken
components.
Display
working?
No
Yes
Go to blank
display
troubleshooting
page 2
Use oscilloscope and tap
touchscreen before
measuring (clock is not
active in partial mode)
Start
End
Change new
display module.
Calibrate
touchscreen
Goto OMAP
troubleshooting
L4427 = 0V
Flash phone.
Display OK?
No
End
Yes