NSW-5
Disassembly and Troubleshooting Instructions
PAMS Technical Documentation
Page 34
Issue 1 10/00
Nokia Mobile Phones Ltd.
Check input level of
buffer (450 kHz) from
capasitor C768
P:
≅
about 6 dB less
than at C770
(IF2–filters input level)
Change IF2–filter(s)
Z750 and/or Z751
Check output level of
buffer from
resistor R798
P:
≅
–13 dBm
Note !
Check comp. R765 & C770
Check input level of
EROTUS IF amplifier
(116.19 MHz
)
from resistor R744
P:
≅
–35 dBm
Change IF1–filter Z741
Note!
Check all components around filter
N
Y
N
Y
N
Y
Check input level of
IF2–filters (
450 kHz) from
capasitor C770
P:
≅
–36 dBm
Change
EROTUS
N750
N
Note !
Check components and
voltages around EROTUS
and also AGC1 line
Y
Change
EROTUS
N750
Note !
Check comp. R798, C750 &
C751 and also check voltages
around EROTUS
TDMA 800
RX–chain is OK.
Start baseband
troubleshooting
(signal go next to
COBBA IC N250)
Check level of IF1 signal
(116.19 MHz
) from MXR
output (N701) pin no.14
P:
≅
–29 dBm
Check level of LO signal
(995.19 MHz
) from LO
input (N701) pin no.1
P: > –3 dBm
Note!
Check all components
around N701
N
Y
Change frontend N701
Y
N
Start synthesizer
troubleshooting
Y
Check level of OSC–sinal
(19.44 MHz
) from
EROTUS (N750) pin no.24
P:
≅
+3 dBm
Start synthesizer
troubleshooting
Y
N
