Receiver Fault Tdma1900 (Only For Dualbander) - Nokia NSC/W–1/3 Series Disassembly & Troubleshooting Instructions

PAMS
Technical Documentation

Receiver Fault TDMA1900 (only for dualbander)

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