Nokia RM-42 Service Manual

Also see for RM-42: Service manual

Contents

Nokia Customer Care Appendix A: RF TroubleshootingA-58Company ConfidentialCopyright © 2005 Nokia. All rights reserved• Measurement can be done with an oscilloscope and a probe.• Connect the probe to R7504.• RB_EXT voltage should be 1.325 – 1.375 V.3.2.2.9.1.2.1 VREFRF01-voltage ok?• Measurement can be done with an oscilloscope and a probe.• Connect the probe to R7503.• VREFRF01 voltage should be 1.325 – 1.375 V. Typical value is 1.35 V.3.2.2.9.1.2.1.1 Desolder R7503. Is VREFRF01 voltage still wrong?Remember to solder a new component to R7503 pads after measurement.3.2.2.9.1.2.1.1.1 Capacitors C7518, C7520 and C7570 working correctly?• 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 capacitors arenot short-circuited. If short-circuit is found replace capacitors mentioned above. If this does nothelp go to the next step.3.2.2.9.1.2.1.1.2 Replace Vinku (N7501) or Hinku (N7500) or both3.2.2.9.1.2.1.2 Retu ok?3.2.2.9.1.2.2 R7521 and R7504 in place and working correctly?• Check that components are in place and solder joints are ok• Disconnect the power supply from the phone and check R521 and R504 resistance values with anohmmeter.3.2.2.9.1.2.3 VB_EXT voltage ok?• Measurement can be done with an oscilloscope and a probe.• Connect the probe to C7518.• VB_EXT voltage should be 1.325 – 1.375 V. Typical value is 1.35 V.3.2.2.9.1.2.3.1 R7503 in place and working correctly?• Check that the component is in place and solder joints are ok• Disconnect the power supply from the phone and check R7503 resistance value with an ohmmeter3.2.2.9.1.2.3.2 Capacitors C7518, C7520 and C7570 working correctly?• Check that components are in place and solder joints are ok