Nokia NHM-4 Series Assembly, Disassembly And Troubleshooting Instructions page 63

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PA&ant. switch
troubleshooting
No
Check with RF probe
PA output signal level *
OK?
No
Check with oscilloscope
-PA Vcc, Vcc1, Vcc2, Vcc3=2.7V
-PA bias = 2.7V pulsed
-VTxLO_GSM = 0V (GSM900)
OK?
Yes
Check modulator
output components
OK?
No
Replace
faulty components
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*When 1kOhm passive probe is used,
correct measurement result by +26dB
Yes Check with oscilloscope
PA ctrl voltage
>1.5V peak
OK?
Tx control line components
Yes No
Replace PA
Yes
Replace HAGAR
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Yes
Yes
Check ant. switch
OK?
Yes
Replace
faulty components
1+0
Replace HAGAR
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