Tdma 800 Rx - Nokia NSW-5 Series Service Manual

PAMS Technical Documentation

TDMA 800 RX

Apply 879.00 MHz
(Ch 300)–60 dBm
signal (no modulation)
to external antenna
connector (X991)
Check level of
IF2–sinal ( 450 kHz )
in RF/BB–interface
from resistor R798
P: ≅ –13 dBm
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
Check level
(879.00 MHz )
from duplex filter
(Z910) input
P: ≅ –60 dBm
Y
Check level
from frontend (N701)
LNA input pin no.7
P: ≅ –60 dBm
Y
Check level
from LNA output
(N701) pin no.10
P: ≅ –40 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
Note!
NOTE! If AMPS RX check is OK, then only
components in AGC1, OUT_rx, IN(N/P)_rxif
Signal level!
and OUT(N/P)_rxif –lines (EROTUS) needs to
be checked.
TDMA 800
Y
RX–chain is OK.
Start baseband troubleshooting
(signal go next to COBBA IC N250)
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
N
Change RX bandfilter Z701
E Nokia Mobile Phones Ltd.
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
(~ 2.8 V at N701 pin no.9)
Note!
Check all soldering
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NSW-5