Tf-4 Synthesizer; General Instructions For Synthesizer Troubleshooting - Nokia 616 Service Manual

TFE-4/RV-1
TF4 Technical Information

TF-4 Synthesizer

There is only one PLL synthesizer generating frequencies for both Rx and TX and for all
two bands (EGSM900 and GSM1800). VCO frequency is divided by 2 or by 4 in Mjoelner
depending on which band is active.

General instructions for Synthesizer troubleshooting

Step 1: Setting up Phone and Phoenix
• Start Phoenix Service Software
• Open the FBUS connection
• Select File /Scan Product (Ctrl-R)
• Wait until phone information shows in the lower right corner of the screen.
• Set operating mode to local mode
• Activate RF-Controls
• Select Maintenance/ Testing/ RF Controls
Wait until the RF Controls window pops up
• Select:
The setup should now look like this:
Step 2: Doing the Measurement
Since VCO chamber is completely shielded, it is not easy to measure frequency of
3769.6MHz at the output of the VCO (G701) using a resistive probe and a spectrum ana-
lyzer. It is possible to measure tuning voltage at charge pump output (C710) easily. For
f = 3769.6MHz the tuning voltage should be 2.3V
VCO
VCO is 240MHz/V typ.).
If this is not the case, then go to section 1.4 of this document for troubleshooting.
Page 8b-60
Company Confidential
Band
Active unit
Operation mode
RX/TX Channel
Copyright © 2005 Nokia Corporation.
Company Confidential
Nokia Customer Care
GSM 900 or GMS1800
RX
Continuous
37 or 700
.. 2.8V (Tuning sensitivity of
DC DC
Issue 2.0 Mar/2005