Afc Voltage Troubleshooting - Nokia 6235 Troubleshooting Manual

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3. On the AMPS Control dialog box, set the Set Channel field to 384, the Power
Level field to 5, and select the Transmitter ON check box. (See
page 12
4. Click the Rx RFI tab, make sure the AFC Control check box is cleared, and click
Execute.
5. The frequency accuracy of the VCTCXO can be measured using an HP8960 callbox
in AMPS mode or a spectrum analyzer at the output of the transmit chain.
• If using a spectrum analyzer, set the center frequency to 836.52MHz and the
span to 2MHz initially. Establish a marker at 836.52Mhz.
• If using an HP8960, set the callbox System Type to AMPS, and set the ACC
channel to 384. Use the Frequency Stability measurement to center the
VCTCXO (minimum Frequency Error).
6. Use the RF PDM component to adjust the AFC to center the VCTCXO. The tuning
range is approximately +/-10kHz.
7. Adjust the AFC so that the output signal is within +/-150MHz. If using a
spectrum analyzer, narrow the span to 1kHz or less.
8. Replace the UEM if the VCTCXO does not tune correctly.

AFC Voltage Troubleshooting

Use the following steps to monitor the AFC voltage.
1. In Phoenix, open the RF PDM dialog box.
Issue 1 04/2005
for an example of the AMPS Control dialog box.)
Figure 46: RF PDM dialog box for AFC troubleshooting
©2005 Nokia Corporation
6235/6235i/6236i (RM-60)
RF Description and Troubleshooting
Company Confidential
Figure 8 on
Page 49