CCS Technical Documentation
Troubleshooting Instructions
NSB-9
Issue 1 04/03
Nokia Corporation
Page 41
Figure 45: FM radio fault finding chart
Set radio channel to
98 MHz
Set audio volume to
maximum (100%)
Apply RF input signal
f
0
= 98 MHz
∆
f= 75 kHz
f
m
= 1 kHz
level= -90 dBm
Turn on FM radio in local
mode. Does the radio start?
8
Check components around
FM radio serial bus and
clock signal (C374, C375,
R357 and R361).
Check 32 kHz clock signal
at J359. Does the radio
start now?
9
Check supply voltages at
TEA5767 (N356) pins 7 and
34 (2.78 VDC).
Does the radio start now?
8
9
Check N356 soldering
(all pins).
Does the radio start
now?
8
9
Replace N356.
Does the radio start
now?
8
9
Baseband digital
failure (UPP)
8
Check audio signal at audio
amplifier N150 input (C170
and C171).
Is the frequency 1 kHz and
amplitude 0.5…0.8 Vpp?
9
Set radio channel and RF
generator to 88.1 Mhz. Re-
check audio signal level
(0.5…0.8 Vpp at C170 and
C171). Re-check also in
107.9 MHz.
9
Audio amplifier failure
(N150)
9
Check RF input
components (C108…C111,
L109, C367, C378, 379 and
L358).
Re-check audio signal at
C170 and C171. Is the
frequency 1 kHz and
amplitude 0.5…0.8 Vpp?
8
Check audio amplifier
output (R164…R167,
L105…L108).
Check audio signal at J103
and J104. Is the frequency
1 kHz and amplitude
0.015…0.3 Vpp?
9
8
9
Check VCO components
(V356,V357, L356, L357,
C357, C358, C362, R359,
R360).
Re-check audio signal
(0.5…0.8 Vpp at C170 and
C171) in 88.1 MHz and
107.9 MHz.
8
9
9
FM radio is OK
8
8
Replace TEA5767
(N356)
Re-check audio signal
(0.5…0.8 Vpp at C170
and C171) in 88.1
MHz and 107.9 MHz.
9
8
Replace transceiver
NSB-9