Nokia 6680 RM-36 Service Manual page 335

Mobile terminal
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Appendix A: RF Troubleshooting
Measurement can be done with an oscilloscope and a probe.
Connect the probe to C7569 (or C7564, C7583)
Voltage level should be 3.05 – 5.4 V. Typical value is 4.0 V.
4.1.2.3.1.2.1 Ferrite Z7500 ok?
Check that component is in place and solder joints are ok
Disconnect the power supply from the phone and use an ohmmeter to check that inductor is
conducting DC.
4.1.2.3.2 Does WCDMA PA (N7503) get correct operating voltage Vcc11?
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)
Measurements can be done with an oscilloscope and a probe.
Connect the probe to C7580.
Vcc11 voltage level should be about 1.5 V. The same voltage level should be measured also with all
power levels smaller than about 10 dBm. Vcc11 is about 3.3 V with the highest power (21 dBm).
NOTE: Perform WCDMA transmitter tests with > 0 dBm power only in RF shielded environment.
4.1.2.3.2.1 L7515, C7589 and C7580 in place and 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 L7515 is
conducting DC.
Use an ohmmeter also to check that capacitors are not short-circuited. If short-circuit is found
replace capacitors mentioned above.
4.1.2.3.2.2 Does SMPS N7504 get operating voltage Vdd (=VBAT_PA)?
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 C7569 (or C7564, C7583)
VBAT_PA voltage level should be 3.05 – 5.4 V. Typical value is 4.0 V.
4.1.2.3.2.3 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.
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