Nokia 2600 服务手册
RH-59/60
Nokia Customer Care
24
COMPANY CONFIDENTIAL
ISSUE 1 09/2004
Copyright © 2004 Nokia. All Rights Reserved.
Troubleshooting diagram for GSM850 receiver
Figure 17:GSM850 receiver troubleshootingt
Apply -55dBm
881.6 MHz
offset 67.71kHz
from generator
to
antenna conn
881.6 MHz
offset 67.71kHz
from generator
to
antenna conn
Oscilloscope
at RX i/Q
signal 588mVpp
DC offset 1.35V
Freq.67.71kHz
at RX i/Q
signal 588mVpp
DC offset 1.35V
Freq.67.71kHz
YES
YES
NO
NO
YES
YES
GSM850
Check RX/TX
Oscilloscope
Check Mjoelner
Check
chain
OK
OK
switch at
RX850
Z700
-56dBm
RX850
Z700
-56dBm
check
VC1 and VC2
at Z700
Signal = 0V
VC1 and VC2
at Z700
Signal = 0V
RX/TX
switch
switch
Spectrum analyzer
Spectrum analyzer
Oscilloscope
Check
Check
GSM850 SAW filter
Z602
output
-65dBm
Z602
output
-65dBm
NO
YES
NO
YES
NO
YES
SAW filter
Z602
Z602
Inductor
L603, L602
L603, L602
check signal after
inductors
L602 and L603
-65DbM
inductors
L602 and L603
-65DbM
VRX 2.7V
Check Mjoelner
serial
interface
Check Mjoelner
serial
interface
Baseband
Check