Pa & Antenna Switch Troubleshooting - Nokia 7600 Troubleshooting Manual

CCS Technical Documentation
PA and Antenna Switch Troubleshooting
Check with RF probe
+4dBm 900MHz
-4dBm 1800MHz
OK ?
Yes
Check with oscilloscope:
VBatt = 3.8V
VCC1 = VCC2 = VCC3 = 3.8V
VTXLO-G= 2.8V pulse (0V GSM1800)
VTXB-G= 2.8V pulsed (0V GSM1800)
VTXB-D= 2.8V pulsed (0V GSM900)
OK ?
No
Check components
around PA
OK ?
No
Replace faulty
component
Issue 1 (11/2003)
Company Confidential
Yes
Check with oscilloscope:
Check Ant Switch
GSM VANT-2 = 2.6V pulse
GSM VANT-1 = 2.6V pulse
Check VANT line components
L638/L639/C551/352
Yes
Yes
Replace PA
Yes
Replace HELGO
Copyright  2003 Nokia Corporation
Company Confidential
6-Troubleshooting
Yes
OK ?
No
OK ?
No
Replace faulty
component
NMM-3
Replace ant.
switch
Page 6-19