Vctcxo Frequency And Output Level Correct; Wcdma Modulation Spectrum And Aclr Ok - Nokia 6680 RM-36 Service Manual

Nokia Customer Care
6.3.5.2 Replace balun T7503

6.3.6 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
1.24 V)".
6.3.6.1 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
6.3.6.1.1 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.
6.3.6.1.2 Replace Retu
6.3.6.1.3 Replace Hinku (N7500) or Vinku (N7501) or VCTCXO (G7501) or all three components
6.3.6.2 BB AFC-voltage ok?
• See section
6.3.6.3 Replace VCTCXO G7501

6.4 WCDMA modulation spectrum and ACLR ok?

• See section 4.3
A-116
"BB AFC-voltage ok?"
"WCDMA modulation spectrum and ACLR
Company Confidential
Copyright © 2005 Nokia. All rights reserved
Appendix A: RF Troubleshooting
6.5.1 "VCTCXO Output (DC Offset
ok?"