Nokia 6021 Service Manual
RM-94
Nokia Customer Care
6(b) - RF Troubleshooting
34
COMPANY CONFIDENTIAL
Issue 1 04/2005
Copyright © 2005 Nokia. All Rights Reserved.
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Fault finding chart for PLL synthesizer
Figure 4:PLL Fault Finding Tree
Yes
Check Baseband part for errors
Phoenix:
Phone is responding to Phoenix commands. For example,
Ctrl-R reads the right phone information.
Ctrl-R reads the right phone information.
No
Synthesizer
Fault Finding Tree
part 1
Fault Finding Tree
part 1
Baseband part is not working,
possible reason: 26MHz missing.
possible reason: 26MHz missing.
Oscilloscope:
Check VCTCXO supply
Check VCTCXO supply
(VR3=2.78V, this can be checked after
power on for a time of about 32sec.
After that time the voltage is going
down.)
power on for a time of about 32sec.
After that time the voltage is going
down.)
Check supply filter components :
C2235, R7516, C7526.
C2235, R7516, C7526.
Check UEM and base band part.
No
Oscilloscope
VCTCXO output at G7501
VCTCXO output at G7501
26MHz,app.0.8Vpp
VCTCXO G7501 defective or
short circuit to GND.
short circuit to GND.
No
Yes
Oscilloscope
REFCLK output of N7500:
Signal VCTCXO=RFCLK_I
at C2902, R2902.
26MHz,app.0.8Vpp
REFCLK output of N7500:
Signal VCTCXO=RFCLK_I
at C2902, R2902.
26MHz,app.0.8Vpp
No
Yes
Check supply filter components:
R7519, C7522, VDIG at N7500
R7519, C7522, VDIG at N7500
Check C2902, R2902 and N7500.
Check UEM and Software.
Check UEM and Software.
Yes