Troubleshooting Diagram For Egsm900 Receiver - Nokia NPM-6 Series Troubleshooting Instructions

Troubleshooting Instructions

Troubleshooting diagram for EGSM900 receiver

Phone in "Continuous" mode, AGC setting "12"
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***
to –50dBm
Frequency 67.7kHz
Yes
900RX chain
functional
Page 18
Figure 11: EGSM900 receiver troubleshooting
Yes No
Spectrumanalyzer
Spectrumanalyzer Spectrumanalyzer
Antenna Switch
Antenna Switch Antenna Switch
outputs,EGSM900 outputs, GSM900 input
–88 dBm –84 dBm
-88dBm
Oscilloscope
VANT_1...3 0V
Yes
Spectrumanalyzer No
HELGA inputs
EGSM900 -89dBm
GSM900
–89 dBm
Yes
Oscilloscope
VR1,3...6 2.7V
No
Check HELGA serial
interface
(burst mode)
Spectrumanalyzer
No
4G VCO out
3769.6MHz
∼–30 dBm (*
Yes
Check HELGA
N500
ãNokia Corporation.
CCS Technical Documentation
No
Check C831,
L811
Yes
No
Oscilloscope :
Check HELGA
serial interface
(burst mode)
Yes
Yes
Check HELGA
N500
Check Antenna
All spectrumanalyzer reading
switch
values are measured with
Z800
2.5 kohm passive probe (use
tweezers to connect the
probe ground to the nearest
PWB ground). Reading value
is represented without
Check L809
+34 dB compensation.
L810
* Spectrumanalyzer
Check Base- reading with 1 kohm
passive probe (right val-
band
ue add +34 dB)
* ** DC–level of RXI/RXQ in
continuous mode will decrease
Synthesiszer trou- slowly.
bleshooting
The original level can be resto-
red by rewriting gain set.
No
Check Base-
band
Issue 1 01/03