Nokia NHL-2NA Series Troubleshooting Instructions page 75

CCS Technical Documentation
Troubleshooting diagram for GSM1800 receiver
Apply –90dBm
1842.86771MHz
signal from generator
to antenna connector
Yes No
Oscilloscope at RX_I
Signal 700mVpp
DC offset 1.35V
Frequency 67.7kHz
Yes
GSM1800 RX chain
functional
Issue 1 07/02
Yes
Change Spectrumanalyzer
generator 1800 SAW i/p
level to -66 dBm
–50dBm
Yes
Spectrumanalyzer
1800 SAW o/p
-71 dBm
Yes
Oscilloscope
VR4 2.7V
Check Hagar
serial interface
(burst mode)
Yes
Spectrumanalyzer
VCO o/p
3685.6MHz
∼-33 dBm (*
Yes
Check Hagar
N505
¤Nokia Corporation
No No
Spectrumanalyzer
1800 ASM RX
-82 dBm
Yes
No
Oscilloscope
LNA_P 0V
LNAB_P 2.6V
Yes
Yes
Spectrumanalyzer
1800 LNA o/p
–58 dBm
No
No
Oscilloscope
1800 LNA o/p 2.6V
1800 LNA i/p 0.8 V
Yes
Check V640,
C632
No
Check Z802,
C630, C631, L630
No
Check Baseband
No
Synthesizer
troubleshooting
NHL-2NA
Check
Antenna
switch
Z672
No
Oscilloscope Check
VR4 2.7V Baseband
Check Hagar
serial interface
(burst mode)
Yes
Check Hagar
N505
Check C640
Check V640,
R642, L640,
R646
All spectrumanalyzer
reading values are
measured with 1 kohm
passive probe (use
tweezers to connect the
probe ground to the
nearest PWB ground).
Reading value is
represented without +26
dB compensation.
* Spectrumanalyzer
reading with 1 kohm
passive probe (right
value add +26 dB)
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