Synthesizer Troubleshooting - Nokia RM-14 Rf Troubleshooting And Manual Tuning

Nokia Customer Care
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Synthesizer troubleshooting

Measure N500 26 MHz reference output voltage at
L515 800 mVpp. OK?
R420
No frequency or wrong frequency ?
No frequency found within the 3-4 GHz span
Measure VCO supply voltage at C560
= 2.8 V OK ?
Replace VCO
8
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 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?
NO
YES
C501
YES
COMPANY CONFIDENTIAL
Copyright © 2004 Nokia. All Rights Reserved.
RF Troubleshooting and Manual Tuning
C527
YES Synthesizer is ok
Wrong frequencies found
Measure VCO control voltage at C505.
Voltage = 4.8V?
VCO does not work or
the control loop is open
Check C503, R501, R502,
Check R502, C503, C504
C504, C505
R501 and C502
RM-14
YES
C504
NO
ISSUE 1 11/04