Nokia 6680 RM-36 Service Manual page 336

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• Voltage level should be about 2.78 V.
4.1.2.3.2.3.1 Replace Vinku (N7501)
4.1.2.3.2.4 Does SMPS get correct control voltage from the WCDMA power detector (signal Vcontrol)?
• WCDMA transmitter has to be active before measurements. Procedure is explained in section
"Transmitter troubleshooting".
• Measurement can be done with an oscilloscope and a probe.
• Connect the probe to C7591.
• Vcontrol signal should be constant DC-voltage. Voltage level should change if TX power is changed.
Vcontrol is lower on lower power levels and higher if higher power levels are used.
• Vcontrol should be about 570 mV with power level +10 dBm, about 2.0 V with power level
+21 dBm and about 200 mV when power levels below 0 dBm are used. NOTE: Perform WCDMA
transmitter tests with > 0 dBm power only in RF shielded environment.
4.1.2.3.2.4.1 Is there correct DET_SW_W –voltage coming from Vinku ASIC (N7501)?
• Measurement can be done with an oscilloscope and a probe.
• Connect the probe to C7586.
• Voltage level should be about 2.78 V.
4.1.2.3.2.4.1.1 Replace Vinku (N7501)
4.1.2.3.2.4.2 Check WCDMA power detector components – In place and value correct?
Components L7514, C7585, V7500, R7526, C7586, R7527, C7587, C7590, R7529,
R7530, C7591, R7531 and C7592.
• Check that components are in place and solder joints are ok
• Disconnect the power supply from the phone and check resistors resistance values with an
ohmmeter
• Use an ohmmeter to check that L7514 is conducting DC.
• Use a diode meter to make sure that diodes inside V7500 are working correctly.
4.1.2.3.2.5 Replace SMPS N7504
4.1.2.3.3 Does WCDMA PA (N7503) get bias currents Icont11 and Icont12?
• WCDMA transmitter has to be active before measurements. Procedure is explained in section
"Transmitter troubleshooting".
• Set TX power level to -40 dBm (Set start level to "-40.0" in phoenix)
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Appendix A: RF Troubleshooting