RAE-6/RA-4
Nokia Customer Care
7 - RF Description and Troubleshooting
44
COMPANY CONFIDENTIAL
Issue 1 12/04
Copyright © 2004 Nokia. All Rights Reserved.
Troubleshooting diagram for synthesizer
Setup with Phoenix:
Active Unit: Rx
Mode: Continuous
Channel:
190 (GSM850)
37 (GSM900)
700 (GSM1800)
661 (GSM1900)
Spectrum analyzer
Check with RF probe
VCO (G7500) out signal:
-3526.4MHz(GSM850)
-3769.6MHz(GSM900)
-3685.6MHz(GSM1800)
-3920MHz(GSM1900)
Level > -10dBm *
OK?
PLL Block is functional
Yes
No
Oscilloscope
VCTCXO Supply
VR3=2.78V
Oscilloscope
VCTCXO output at G7501
26MHz,app.0.8Vpp
Check supply filter components :
C2232, C7590.
Check UEM and SW.
Oscilloscope
VCO supply
VR7 = 2.78V, VR5=2.78V,
VR1=4.7V
Spectrum analyzer
VCO (G7500) out
Some signal 3-4.4 GHz
Check VCO G7500,
Balun T7500
Check loop filter components:
C7503, C7504, C7505, R7501, R7502
Wrong writing on RFBus (see BB part)
If ok change RF ASIC N7500
Check supply filter components:
R7500, C7501, C7560, C2230, C7551,
C7552, C7553
Check UEM and Software.
Yes
Yes
Yes
No
No
No
No
Yes
G7501 defective or short
Circuit to GND
* When 1 kOhm passive probe is used,
Correct the measurement by +26dB
Troubleshooting diagram for synthesizer
R7500, C7501, C7500, C7505
C7502, C7519,
R7501, R7502
Wrong writing on RFBus (see BB part)
If ok, change RF ASIC N7500
Fault is in non-reworkable
component. Refer to
current BR handling guidance.