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