Nokia Customer Care
Appendix A: RF Troubleshooting
A-88
Company Confidential
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2005 Nokia. All rights reserved
•
Spectrum analyser RBW = VBW = 10 MHz, Span
≤
2 MHz, sweep time 100 ms.
•
Connect the RF probe to L7511. The RF-level should be about the same on both ends of the
inductor. Check the level with 0 dBm power level (Set start level “0” to Phoenix).
•
Power level “0” – Vinku output level should be about -40…-48 dBm
4.1.2.2.1.1 Inductor L7511 and resistor R7520 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 R7520 resistance value with an
ohmmeter.
•
If resistance of R7520 is correct then replace L7511.
4.1.2.3 Does WCDMA PA (N7503) transmit correct RF-power?
•
WCDMA transmitter has to be active before measurements. Procedure is explained in section
“Transmitter troubleshooting”.
•
Set TX power level to 0 dBm (Set start level “0” to Phoenix)
•
Measurements can be done with a spectrum analyser and an RF probe. Remember to make correct
frequency setting to the spectrum analyser. Spectrum analyser centre frequency should be set
according the used TX channel (see section “Frequency mappings”).
•
Spectrum analyser RBW = VBW = 10 MHz, Span
≤
2 MHz, sweep time 100 ms.
•
Connect the probe to Z7505 input. The RF level should be roughly -16…-28 dBm.
4.1.2.3.1 Does WCDMA PA (N7503) get correct operating voltage Vcc12?
•
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 R7525
•
Vcc12 voltage level should be 3.05 – 5.4 V. Typical value is 4.0 V.
4.1.2.3.1.1 R7525 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 R7525 resistance value with an ohmmeter
4.1.2.3.1.2 PA operating voltage VBAT_PA ok?
•
WCDMA transmitter has to be active before measurements. Procedure is explained in section
“Transmitter troubleshooting”.
