Nokia NHL-4J Series Troubleshooting Instructions page 11

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PA & ant switch
troubleshooting
Yes
Check with RF probe
signal level on
PA input >=0dBm (*
OK ?
Yes
Check with
oscilloscope:
-VBATT ~4V
- VTXB = 2.8 V pulsed
- VTxLO_GSM = 0V (GSM900)
OK ?
No
Check components
around PA
OK ?
No
Replace
faulty
component(s)
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*(When 1kOhm passive probe is used,
correct the measurement by +26dB
Check with
Yes
oscilloscope:
-VANT_1 (GSM900)
-VANT_2 (GSM1800)
-VANT_3 (GSM1900)
Yes
Replace
PA
Yes
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OK ?
No
Check
VANT lline components
OK ?
Yes
Replace
faulty
component(s)
Replace
HELGA
1+/-
Replace
ant. switch
No
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