NAD S400, Service Manual

Page: 6 / 31

Pr
el
im
in
ar
y
4) With the same oscilloscope setup as in procedure #3, press the
ANTENNA
button and select
ANTENNA
port
#
1
. Check that the IF-signal is reduced by a minimum of 40 dB.
5) Connect the signal generator to ANTENNA port # 1 . With the same oscilloscope setup as in
procedure #3, adjust
L2
until the IF-signal is at maximum setting. Press the
ANTENNA
button and
select ANTENNA port # 2 . Check that the IF-signal is reduced by a minimum of 40 dB.
NOTE: Return to step #3 and perform the same alignment procedure but substitute L2 for L1 . Continue to
align L10 , L7 , L2 , and L1 , until there is no improvement in IF-level maximum level between the two antenna
ports, and that the isolation between the two ports is greater that 40 dB.
Alignment of IF Section:
6) Connect an RF signal generator to ANTENNA port # 1 and set to:
Amplitude = 45 dBu
Pilot tone = off
Modulation = off
Frequency = 98.000 MHz.
Press the ANTENNA -button and select ANTENNA port # 1 . Press the IF -button to select IF WIDE .
With the same oscilloscope setup as in procedure #3, check that the IF-signal had increased
approximately 3 dB compared to IF NARROW .
Remove the oscilloscope probe from the common point between CF3 and CF4 .
7) Connect an RF signal generator to ANTENNA port # 1 and set to:
Amplitude = 70 dBu
Pilot tone = off
Modulation = off
Frequency = 98.000 MHz.
Adjust L13 (or VR1) until the centre-tune LED turns on. Fine adjust VR1 so that it lights from
approximately 97,965 MHz. to 98,035 MHz equally.
Alignment of Audio Section:
8) Set the S400 as the following:
Press the IF -button to select IF WIDE .
Press the ANTENNA -button and select ANTENNA 1 .
Press the MONO/MUTE -button to MUTE OFF MONO .
Press the BLEND -button to BLEND OFF.
Press the BANDWIDTH -button to BANDWIDTH WIDE.
Tune the
S400
to 98.00 MHz.
9) Connect an audio AC voltmeter with decibel display to both the right and left audio output jacks. Set
the AC-voltmeter to negative 30 dB range.
Leave the audio AC-voltmeter attached to the S400
audio output jacks until told to remove it.
Then connect an RF signal generator to ANTENNA port # 1 and set to:
Amplitude = 45 dBu
Pilot tone = on (19 kHz @ 10%)
Modulation = off
Frequency = 98,00 MHz
10) Adjust L3 for a minimum 19 kHz output at the right audio jack.
11) Adjust L4 for a minimum 19 kHz output at the left audio jack
NAD S400