Nokia NEM-4 Series Troubleshooting Instructions page 92

NEM-4 Company Confidential
RF Troubleshooting CCS Technical Documentation
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 .. 2.8V (Tuning sensitivity of
VCO DC DC
VCO is 240MHz/V typ.).
Figure 3: PLL Synthesizer Test Points
If this is not the case, then go to Fault finding chart in this document for Troubleshoot-
ing.
Copyright  2003 Nokia Corporation.
Page 6(b)-88 Issue 1 09/2003
Company Confidential