Troubleshooting Charts For The Receiver Chain; Amps Rx - Nokia NSW-5 Series Service Manual

PAMS Technical Documentation

Troubleshooting charts for the receiver chain

AMPS RX

Apply 879.00 MHz (Ch 300)
–116 dBm , 8kHz dev,
1 kHz sine signal
(FM modulation)
to external antenna
connector (X991)
Connect EXT HS to
audioanalyzator.
Open audio
AF: 1 kHz sine signal,
meas SINAD
SINAD: > 12 dB
N
Check UHF VCO
control voltage from
capasitor C831
V: 1.0 4.0 V
Y
Check 3 multiplier output
level ( 58.32 MHz )
from coil L762
P: ≅ –10 –20 dBm
Y
Apply 879.00 MHz
–50dBm , carrier signal
(no modulation)
to external ant. connector
Check level
from duplex filter
(Z910) input
P: ≅ –50 dBm
Y
Check level
from frontend (N701)
LNA input pin no.7
P: ≅ –50 dBm
Y
Check level
from LNA output
(N701) pin no.10
P: ≅ –30 dBm
Y
Check level from MXR
input (N701) pin no.12
P: ≅ 0–2 dB less than at LNA
output pin no.10
Y
Issue 1 10/00
Disassembly and Troubleshooting Instructions
Y
AMPS
RX–chain OK
N
Start synthesizer
troubleshooting
N
Start synthesizer
troubleshooting
N
Change diplexer Z970
N
Change duplex filter Z910
or coil L701
N
Change frontend N701
N
Change RX bandfilter Z701
E Nokia Mobile Phones Ltd.
Note!
Signal level
Note!
Check all soldering and
Components in antenna
circuit before changing
Note!
Check all soldering and
discrete components of
frontend.
Note!
AGC2 is on
= gain is in high state
(~2.8V at N701 pin no.9)
N
Note!
Check all soldering
NSW-5
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