User Guide

RH-30/RH-31 Company Confidential
Troubleshooting Instructions Nokia Customer Care
Page 10 © 2004 Nokia Corporation. Issue 2 11/2004
Transmitter troubleshooting diagram
Figure 3: Transmitter troubleshooting
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TX Troubleshooting
Check output signal level:
+32…+33dBm@897.4MHz(GSM900)
+29…+30dBm@1747.8 and 1880MHz
(GSM1800&1900)
OK?
Check
all power
levels,
OK?
TX OK
Tune
TX power
levels,
OK?
TX si
g
nal found?
Check output signal
on 500MHz span
Signal found on incorrect
frequency?
Synthesizer
troubleshootin
g
Check with RF probe signal level on
PA input: >=0dBm
OK?
Helgo
troubleshootin
g
Start TX power level tuning and check tuned DAC values:
Highest level ~670…850(GSM900); ~580…700(GSM1800&1900)
Lowest level ~170…200(GSM900); ~180…220(GSM1800&1900)
Base level ~140…170(GSM900); ~135…165(GSM1800&1900)
Major differences?
Tune TX DAC values
Check control voltage with
oscilloscope:
PA Ctrl voltage >1.5V peak
OK?
Check control loop
components
OK?
Replace Helgo
PA & ant switch
troubleshooting
Replace faulty
com
p
onents
+32...+33dBm@836.6MHz (GSM850)
+32...+33dBm@897.4MHz (GSM900)
+29...+30dBm@1747.8MHz and 1880MH
z
(GSM1800 and 1900) OK?
Highest level ~670...850(GSM850/900);~580...700(GSM1800/1900)
Lowest level ~170...200(GSM850/900);~180...220(GSM1800/1900)
Base level~140...170(GSM850/900);~135...165(GSM1800/1900)