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