Vctcxo Troubleshooting; Vctcxo Manual Tuning - Nokia 6235 Troubleshooting Manual

6235/6235i/6236i (RM-60)
RF Description and Troubleshooting

VCTCXO Troubleshooting

Without 19.2MHz, the mobile terminal does not power up. This signal goes to the N7100,
N7000, D2800, and the UHF PLL. Check the test points in
the 19.2MHz signal.
If you do not see the VCTCXO signal at any of these points, check voltage at VR3, main
supply line for VCTCXO, it should be 2.78VDC.
Also check the AFC voltage, it should be between 1 and 3 volts. The voltage should be
adjustable with the AFC slider on the RF PDM Control in Phoenix. See
Troubleshooting" on page 49. If AFC voltage is missing, check the UEM.

VCTCXO Manual Tuning

The VCTCXO can be manually tuned to verify when a mobile terminal is tuned incorrectly
or if mobile terminal cannot make a call. Monitor the RF signal at the mobile terminal's
output.
1. On the Phone Control dialog box, click the LOCAL button in the Phone State
area to put the mobile terminal into Local Mode. (See
example of the Phone Control dialog box.)
2. Click the Execute button.
Page 48
Figure 45: VCTCXO test point output values
©2005 Nokia Corporation
Figure 45
Figure 7
Company Confidential
for the presence of
"AFC Voltage
on page 11 for an
Issue 1 04/2005