Nokia RM-42 Service Manual page 369

Appendix A: RF Troubleshooting
should be about 0 V before transceiver activation.
4.2.4.2.1 RAP3G (or Vinku or Hinku) faulty?
• RAP3G (D2800) cannot be replaced.
4.2.4.3 Hinku (N7500) regulator voltage VR1 ok?
• WCDMA receiver has to be active before Hinku's VR1 voltage can be measured. Procedure is
explained in section "Receiver troubleshooting".
• Measurements can be done with an oscilloscope and a probe.
Connect the probe to C7504 (or C7505)
•
• VR1 voltage level should be 2.65 – 2.86 V. Typical value is 2.7 V.
4.2.4.3.1 Hinku (N7500) RB_EXT voltage ok?
WCDMA receiver has to be active before Hinku's RB_EXT voltage can be measured. Procedure is
•
explained in section "Receiver troubleshooting".
• 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.
4.2.4.3.1.1 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.
4.2.4.3.1.1.1 Desolder R7503. Is VREFRF01 voltage still wrong?
Remember to solder a new component to R7503 pads after measurement.
4.2.4.3.1.1.1.1 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 are
not short-circuited. If short-circuit is found replace capacitors mentioned above. If this does not
help go to the next step.
4.2.4.3.1.1.1.2 Replace Vinku (N7501) or Hinku (N7500) or both
4.2.4.3.1.1.2 Retu ok?
4.2.4.3.1.2 R7521 and R7504 in place and working correctly?
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