Nokia RM-42 Service Manual

Also see for RM-42: Service manual

Contents

Nokia Customer Care Appendix A: RF TroubleshootingA-28Company ConfidentialCopyright © 2005 Nokia. All rights reservedhelp go to the next step.3.1.1.1.3.1.3.3 Replace Vinku (N7501) or Hinku (N7500) or both3.1.1.1.3.1.4 Replace Vinku (N7501)3.1.1.1.3.2 Are capacitors in Vinku (N7501) regulator lines working correctly?VREG1: C7543VREG2: C7547, C7548, C7554, C7555, C7553, C7552, C7558 and C7567• Check that components are in place and solder joints are ok• Disconnect the power supply from the phone and use an ohmmeter to check that regulator linesare not short-circuited to the ground. If short-circuit is found replace capacitors mentioned above.If this does not help go to the next step.3.1.1.1.3.3 TX VCO (G7502) ok?3.1.1.1.3.4 Replace Vinku (N7501)3.1.1.1.4 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 V3.1.1.1.4.1 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 isshort-circuited to the ground. If short-circuit is found replace C7560, C7513, C7526 and C2214. Ifreplacing does not help then go to the next steps.3.1.1.1.4.2 Replace Retu3.1.1.1.4.3 Replace Hinku (N7500) or Vinku (N7501) or VCTCXO (G7501) or all three components3.1.1.1.5 VCP2-voltage ok?• GSM transmitter has to be active before VCP2 voltage can be measured. Procedure is explained insection “Transmitter troubleshooting”.• Measurement can be done with an oscilloscope and a probe.• Connect the probe to C2221 (or C7550).• VCP2 voltage should be about 4.75 V.