RM-14
Nokia Customer Care
RF Troubleshooting and Manual Tuning
8
COMPANY CONFIDENTIAL
ISSUE 1 11/04
Copyright © 2004 Nokia. All Rights Reserved.
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Synthesizer troubleshooting
Synthesizer Troubleshooting
Phoenix: RF local mode Rx continuous
Frequency = 3770.4 MHz @ ch. 38
Measure G501 VCTCXO output voltage at G501 pin 3
26 MHz 900 mVpp. OK ?
Measure N500 26 MHz reference output voltage at
Measure G501 VCTCXO AFC voltage at C540.
Measure RF frequency and level at T500.
Place the probe through the hole in the shield!
Correct frequency found?
YES
NO
No frequency or wrong frequency ?
Synthesizer is ok
No frequency found within the 3-4 GHz span
Wrong frequencies found
Measure VCO supply voltage at C560
= 2.8 V OK ?
Replace VCO
YES
Measure VCO control voltage at C505.
YES
YES
VCO does not work or
the control loop is open
NO
Check C503, R501, R502,
C504, C505
L515 800 mVpp. OK?
Voltage = 4.8V?
R420
C527
C504
C501
Check R502, C503, C504
R501 and C502