CCS Technical Documentation
Troubleshooting
RH-13
Issue 1 11/02
ã
Nokia Corporation
Page 43
Figure 26:
Fault finding chart.
Step 1. Local oscillator checking
Carrying out this step VCO signal of 1st and 2nd mixers can be checked. 2nd mixer RX
VHF VCO frequency is constant 268.08 MHz but for the 1st mixer UHF VCO frequency
depends on the channel. The UHF VCO frequencies for the 1st mixer are:
Apply signal to ext.
antenna connector
f= 1960.029 MHz ch
1000)
unmodulate
level= -50 dBm
Check signal level
at RX I/Q J808,
J809, J818, J819
OK
TDMA1900 RX is
OK
Not OK
Check signal level
at diplexer Z908
input
Replace external
antenna connector
X900
Not OK
OK
Check signal level
at duplex filter
Z962 input
Replace diplexer
Z908
Not OK
OK
Check signal level
atLNA V804 input
Replace duplex
filter Z962
Not OK
OK
C heck signal level
at R X band filter
Z 802 input
C heck components
around lna and
measure supply
voltages
Not O K
O K
C heck signal level
at mix1_B input
R eplace R X band
filter Z 802
Not O K
O K
C ontinue
troubleshooting as
in
A MPS/T D MA 800