PAMS
Technical Documentation
NSC/W–1/3
Disassembly & Troubleshooting Instructions
Page 25
Original 11/99
Receiver Fault TDMA1900 (only for dualbander)
Apply 1960.02 MHz
–50dBm signal to
external RF–connector
X991.
Check 3 multiplier
output level TP2LU
V: >150 mVpp
N
N
N
Check input level
of duplex filter (Z960)
P:~–50 dBm
Check input level of
frontend N721
Check output level at
LNA out pin 10
P:~–55 dBm
Check RF level of
COBBA_D pin no 10
P: ~–13 dBm
Check UHF Vcnt
TP5U
V: 2.0...2.5V
Start synthesizer
troubleshooting
TDMA1900
RX–chain is OK
Y
N
N
Y
N
Start synthesizer
troubleshooting
Change EXT RF
Connector
Note!
Check all soldering and components
in antenna circuit before changing
N
Y
Y
Change duplex filter or
L721
Note!
Check all soldering and discrete
components of frontend.
Change N721
Y
Note!
AG2 is on
Check MXR RF level
P:~0–2 dB less than in
Change RX band filter
Z726
Note!
Check all soldering
N
Y
Check all components around of N721
N
Y
N880, pin 3
N750, pin 42
pin 7
P:~–52 dBm
pin 12
LNA output pin no. 10