Nokia RM-12 Troubleshooting Instructions page 9

CCS Technical Documentation
Transmitter troubleshooting diagrams
TX Troubleshooting
Check output signal level:
+32...+33dBm@897.4MHz(GSM900)
+29...+30dBm@1747.8 and 1880MHz
(GSM1800&1900)
OK?
No
TX signal found?
Yes
Check with RF probe signal level on
PA input: ~ -1...+5dBm
OK?
Yes
Start TX power level tuning and check tuned coefficient values:
Highest level ~0.655...0.831(GSM900); ~0.567...0.782(GSM1800&1900)
Yes
Lowest level ~0.166...0.196(GSM900); ~0.176...0.225(GSM1800&1900)
Base level ~0.137...0.166(GSM900); ~0.132...0.161(GSM1800&1900)
Major differences?
No
Check control voltage with
oscilloscope:
PA Ctrl voltage >1.5V peak
OK?
Yes
PA & Antenna Switch
troubleshooting
7
Figure 3: Transmitter troubleshooting
TX OK
Yes
Yes
Check
all power
levels,
OK?
Check output signal
No
on 500MHz span
Signal found on incorrect
frequency?
No
No
Check control loop
components
No
Replace faulty
components
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Yes
Tune
No
TX power
levels,
OK?
Yes
Helgo
troubleshooting
Yes
Tune TX coefficient
values
Yes
OK?
No
RM-12
No
Synthesizer
troubleshooting
Replace Helgo
Issue 1 11/2004