Fault Finding Tree - Nokia NHL-2NA Series Troubleshooting Instructions

NHL-2NA

Fault finding tree

Tx troubleshooting
Check output signal level
from antenna connector
+32dBm@897.4MHz (GSM900)
+29dBm@1747.8MHz (PCN1800)
OK?
NO
Tx signal found?
YES
Check with RF probe signal level
on PA input
-6 dBm on 900 PA i/p
-23 dBm on 1800 PA i/p
OK?
YES
Start TX power level
tuning and check
tuned DAC values:
Highest level 700(GSM900)
Highest level 600(PCN 1800)
Lowest level 170
Base level 150
Major differences?
NO
Check with oscilloscope
900 & 1800 PA CONTROL
>2.4V peak
OK?
YES
PA&ant.switch
troubleshooting
Page 14
Tx OK
YES
Check all
power levels
YES
OK?
Check output signal
on 500MHz span
NO
Signal found on
incorrect frequency?
NO
Check GSM tx filter/
PCN tx balun input level
-9 dBm on 900 FILT i/p
NO
-24 dBm on 1800 BALUN i/p
OK?
YES
Replace faulty
components
YES
Check power control
NO
loop components
OK?
NO
Replace faulty
components
¤Nokia Corporation
CCS Technical Documentation
YES
Tune TX power
NO
levels OK?
Synthesizer
YES
troubleshooting
NO
troubleshooting
Tune TX DAC
values
YES
Hagar
Replace HAGAR
Issue 1 07/02