Vctcxo Tuning - Nokia RH-77 Troubleshooting Manual

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VCTCXO Tuning

The VCTCXO can be manually tuned to verify failed tuned mobile terminals, or to verify if
a mobile terminal cannot make a call. This can be done with the mobile terminal in Local
Mode and generating a CW signal. The frequency accuracy of the VCTCXO can be
measured using an HP8960 callbox in AMPS mode, an HP4406 Tx tester, or a spectrum
analyzer (preferably using a lab system 10MHz source as equipment reference). Replace
the VCTCXO if the VCTCXO AFC DAC value does not meet the tuning requirements after
tuning.
Use the following steps to manually tune the VCTCXO:
1. Open the Phone Control dialog box.
Figure 23: Phone Control dialog box for VCTCXO troubleshooting
2. Click the LOCAL button in the Phone State area to put the mobile terminal into
Local Mode.
3. Select the following values on the RF Main Mode dialog box:
Band = Cell (CDMA)
•
Channel = 384
•
Mode = Rx/Tx
•
Issue 01 04/2005
©2005 Nokia Corporation
RF Description and Troubleshooting
Company Confidential
2118 (RH-77)
Page 33