Nokia NSW-5 Series Service Manual page 238

NSW-5
Disassembly and Troubleshooting Instructions
Y
Check level of IF1 signal
(116.19 MHz ) at MXR
output (N701) pin no.14
P: ≅ –19 dBm
Y
Check input level of
EROTUS IF amplifier
(116.19 MHz ) from R744
P: ≅ –25 dBm
Y
Check input level of
IF2–filters ( 450 kHz ) from
capasitor C769
P: ≅ +1 dBm
Y
Check level of limiter
input (450 kHz ) from
capasitor C767
P: ≅ about 6 dB less
than at C769
(IF2–filters input level)
Y
Check level of limiter
output from coil L750
P: ≅ –10 dBm
Y
AMPS 800
RX–chain is OK.
Start baseband
troubleshooting
(signal go next to
COBBA IC N250)
Page 32
N Check level of LO signal
(995.19 MHz ) from LO input
(N701) pin no.1
P: > –3 dBm
Y
Change frontend N701
N
Change IF1–filter Z741
Check level of OSC–sinal
N
(19.44 MHz ) from
EROTUS (N750) pin no.24
P: ≅ +3 dBm
Change
EROTUS
N750
N
Change IF2–filter(s)
Z750 and/or Z751
N
Change
EROTUS
N750
E Nokia Mobile Phones Ltd.
PAMS Technical Documentation
N
Start synthesizer
troubleshooting
Note!
Check all components
around frontend N701
Note!
Check all components
around filter
N
Start synthesizer
troubleshooting
Y
Note !
Check components and
voltages around EROTUS
Note !
Check comp. R764 & C769
Note !
Check comp. R788, R789,L750,
C780 & R774 and also check
voltages around EROTUS
Issue 1 10/00