User Guide

NHL-12
Nokia Customer Care 7 - RF Description & Troubleshooting
32 COMPANY CONFIDENTIAL Issue 2 10/2004
Copyright © 2004 Nokia. All Rights Reserved.
Figure 15:Transmitter EDGE troubleshooting
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TX EDGE Troubleshooting
Check output signal level:
+24…+30dBm@897.4MHz(GSM900)
+22…+29dBm@1747.8 and 1880MHz
(GSM1800&1900)
OK?
Check
all power
levels,
OK?
TX OK
Tune
TX power
levels,
OK?
TX signal found?
Check output signal
on 500MHz span
Signal found on incorrect
frequency?
Synthesizer
troubleshooting
Check with RF probe signal level on
PA input:
~-8dBm@PCL=8 (GSM900
~-10dBm@PCL=2 (GSM1800&1900)
OK?
Helgo EDGE
troubleshooting
Start TX Edge power level tuning and check tuned coefficient values:
Highest level ~700…800(GSM900); ~630…730(GSM1800&1900)
Lowest level ~340…410(GSM900); ~250…360(GSM1800&1900)
Base level ~190…260(GSM900); ~150…250(GSM1800&1900)
Major differences?
Tune TX DAC values
Check control voltages with
oscilloscope:
Pa Iref ~2V peak (GSM900
Pa Iref ~2.1V peak (GSM1800@1900)
Mode ~1.8V OK?
Check EDGE control
loop components
OK?
Replace Helgo
PA & ant switch
EDGE troubleshooting
Replace faulty
components
+24...+30dBm@836.6MHz(GSM850)
+24...30dBm@897.4MHz(GSM900)
+22...+29dBm@1747.8and 1880MHz
(GSM1800/1900)
OK?
(GSM850)
Highest level~0.750...0.930(GSM850);~0.690...0.900(GSM1800&1900)
Lowest level~0.420...0.550(GSM850);~0.350...0.470(GSM1800&1900)
Base level~0.200...0.400(GSM850);~0.210...0.410(GSM1800&1900)
(GSM850)