User Guide

PAMS Technical Documentation 6 - Troubleshooting
NPE-4
Original ãNokia Corporation. Page 6-31
Fault finding chart for EGSM receiver
EGSM Signal path
For easy error tracing it is important to know the signal path of the EGSM receiver. The
compnents can be grouped into blocks and drawn as shown below. Note that the picture
shows bothe EGSM receiver (bottom) and PCN (top).
Tba
RX/TX Switch
From the antenna-pad (X800) the RF signal is lead to the RX/TX switch (Z802) via a
mechanical switch, the antenna connector (X802).
Apply -80dBm
942.467MHz signal from
generator to antenna
connector
Oscilloscope at RXIINP
Signal 950mVpp
DC offset 1,1V
Frequency 67,7kHz
EGSM chain functional
Oscilloscope
VR4 2.7V
Check Hagar serial
interface
Yes
Yes
Yes
Spectrumanalyzer
V820, RFout
-73dBm
No No
Spectrumanalyzer
DUAL SAW
(Z804) EGSM out
-85dBm
Spectrumanalyzer
DUAL SAW
(Z804) EGSM in
-84dBm
No
Spectrumanalyzer
Z620 input
-75dBm
Check
C824
No
Yes
Check Hagar
N600
Yes
Check BBNo
Oscilloscope
LNAC_900
2.4-2.8V
LNAB_900 0V
Yes
Check RX/TX
Switch
Z802
No
Check Z804
Yes
No
Oscilloscope
V820, RFout 2.1-2.2V
V820, RFin 0.8-0.9V
Yes
Oscilloscope
VR4 2.7V
Check Hagar serial interface
Check Hagar
N600
Yes
Check BaseBandNo
Check
R822,R823,R828,
V820,C821,C822,
C828, L822
No
Check
V820
Yes
Change generator
level to -55dBm
Yes
EGSM RX Fault finding Tree