Nokia RM-57 Service Manual page 271

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3.2.2.5 VCP1-voltage ok?
• GSM receiver has to be active before VCP1 voltage can be measured. Procedure is explained in
section "GSM RX chain activation for manual measurements".
• Measurement can be done with an oscilloscope and a probe.
• Connect the probe to C7507.
• VCP1 voltage should be about 4.75 V.
3.2.2.5.1 C7507 and C2222 working properly?
Check that the components are in place and solder joints are ok
•
• Disconnect the power supply from the phone and use an ohmmeter to check that C507 and
C2222 are not short-circuited.
3.2.2.5.2 Retu ok?
3.2.2.5.3 Hinku (N7500) ok?
3.2.2.6 VCTCXO frequency and output level correct?
• Measurement can be done with an oscilloscope and a probe.
Connect the probe to C7529 (or C7582)
•
• The frequency of the VCTCXO should be quite exactly 38.4 MHz and level about 0.5 - 0.9 Vpp.
Example of the correct VCTCXO output signal is presented in figure
Offset 1.24
3.2.2.6.1 VXO-voltage ok? (=Vdig).
• Measurement can be done with an oscilloscope and a probe
• Connect the probe to C7560 (or C7526, C7513)
• VXO-voltage should be about 2.5 V
3.2.2.6.1.1 C7560, C7513, C7526 and C2214 ok?
• Check that components are in place and solder joints are ok
Disconnect the power supply from the phone and use an ohmmeter to find out if the VXO-line
•
is short-circuited to the ground. If short-circuit is found replace C7560, C7513, C7526 and
C2214. If replacing does not help then go to the next steps.
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Appendix A: RF Troubleshooting
4.6.1 "VCTCXO Output (DC
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