Nokia RH-18 - Troubleshooting Chart for Gsm1800 Receiver

CCS Technical Documentation
Company confidential RH-18/38
Issue 1 10/03 Nokia Corporation. Page 39
Troubleshooting Chart for GSM1800Receiver
Figure 35: GSM1800 receiver Troubleshooting chart
Apply -55dBm
1842.8 MHz
offset 67.71kHz
from generator
to
antenna conn
Oscilloscope
at RX i/Q
signal 588mVpp
DC offset 1.35V
Freq.67.71kHz
YES
YES
NO NO
YES
YES
EGSM
Check RX/TX
Oscilloscope
Check Mjoelner
Check
chain
OK
switch at
RX1800
Z700
-56dBm
check
VC1 and VC2
at Z700
Signal = 0V
RX/TX
switch
Spectrum analyzer
Spectrum analyzer
Oscilloscope
Check
Check
EGSM SAW filter
Z601
output
-65dBm
NO
YES
NO
YES
NO
YES
SAW filter
Z602
Inductor
L603, L602
check signal after
inductors
L601 and L611
-65DbM
VRX 2.7V
Check Mjoelner
serial
interface
Baseband
Check