Receiver Troubleshooting Diagram For Gsm900 - Nokia NHM-7 Series Troubleshooting Manual

PAMS Technical Documentation

Receiver troubleshooting diagram for GSM900

Receiver troubleshooting diagram for GSM900
Apply –90dBm
942.46771MHz signal
from generator to anten-
na connector
Yes No
Oscilloscope at RX_I Change ge-
Signal 700mVpp
nerator level
DC offset 1.35V Fre-
to –50dBm
quency 67.7kHz
Yes
EGSM RX chain func-
tional
,VVXH  
Troubleshooting and Tuning Instructions
Yes No
Spectrumanalyzer Spectrumanalyzer
900 LNA out 900 1st SAW out
–61 dBm –80 dBm
Oscilloscope
LNA_G 2.7V
LNAB_G 2.7V
Yes
Spectrumanalyzer
V500, RFout
dBm
Oscilloscope
V500, RFout 2.7V
V500, RFin 0.8 V
Check V500, C501,
L502, L503
No
Spectrumanalyzer Check Z501, C505,
900 bal out C506, L501
–66 dBm
Yes No
Oscilloscope Check Baseband
VR4 2.7V
Check Hagar serial
interface (burst mo-
de)
Yes No
Spectrumanalyzer Synthesizer troubles-
4G VCO out hooting
3769.6MHz
∼–30 dBm (*
Yes
Check Hagar N600
1RNLD &RUSRUDWLRQ
No
Spectrumanalyzer
900_RX
–79 dBm
Yes
Check dual RX SAW
Z520
Yes
No No
Oscilloscope
VR4 2.7V
Check Hagar seri-
al interface Check
R501
Yes
Yes
Check Hagar
N600
Yes
Check C502
–57
No No
Check V500,
L500, R502
Yes
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 val-
ue add +26 dB)
NHM-7
No
Check An-
tenna switch
Z500
Check Base-
band
3DJH