Transmitter Troubleshooting Diagram - Nokia NPM-6 Series Troubleshooting Instructions

CCS Technical Documentation

Transmitter troubleshooting diagram

TX troubleshooting
Check output signal level:
+32...+33dBm @897.4 MHz (GSM900)
+29...+30dBm @1747.8 MHz
(GSM1800 & GSM1900)
OK ?
TX signal found ?
Yes
Check with RF probe
signal level on
PA input >=0dBm (*
OK ?
Yes
start TX power level
tuning and check
tuned RAC values:
Highest level~700...900
Lowest level ~190...210
Base levle ~160...190
Major differences ?
No
Check with oscilloscope:
PA ctrl voltage
>1.5V peak OK ?
Yes
PA & ant switch
troubleshooting
Issue 1 01/03
Figure 3: Transmitter troubleshooting
TX OK
Yes
(EGSM900 Check
Yes
all power
levels,
OK ?
No
Check output signal
on 500 MHZ span
Signal found on
incorrect frequency ?
No
No
HELGA
troubleshooting
*(When 1kOhm passive probe is used,
correct the measurement result by +26dB
Yes
Tune Tx DAC values
Check control loop
components
OK ?
No
Yes
Replace
faulty
component(s)
ãNokia Corporation.
Troubleshooting Instructions
Tune
No
TX power
levels,
OK ?
Yes
Synthesizer
troubleshooting
Yes
Replace HELGA
dead
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