NAD 7155 - AM Alignments; Oscillator Alignment; Antenna and IF Alignment; Whistle Filters

AM ALIGNMENTS
A
wn
aR won
OSCILLATOR.
Connect DMM to TP 101 and gnd.
Tune to 1710 kHz, Enter into preset 1. Adjust C 148 for reading of 31 + 0.5VDC,
Tune to 520 kHz. Enter into preset 2. Adjust L 103 for reading of 1.8 + 0.1 VDC.
Repeat steps 2 and 3 until within tolerances.
ANTENNA, IF
Swing
antenna
away
from
chassis
and
peel
back
label
(if
present)
to
expose
adjustment
tab.
Connect DC voltmeter to centertap, R 208 and gnd.
Tune
to
station
of
moderate
strength,
near
600
kHz.
Enter
into
preset
3.
Adjust
L
951
(move
tab
under
label
on
antenna)
for
maximum
reading
on
meter.
(Use
non-ineractive
tool,
such
as
plastic
or
wooden
stick.)
Adjust L 104 and L 106 for maximum reading on meter.
Tune
station
of
moderate
strength
near
1400
kHz.
Enter
into
preset
4.
Adjust
C
147
for
maximum
reading
on
meter.
Repeat steps 3 and 5 until no further improvement is seen.
9 kHz, 10 kHz WHISTLE FILTERS
Tune to quiet spot on the dial (a clear frequency)
Connect audio osc. to base, Q 117 (isolate with 0.1 - 1.0 uF capa.)
Connect AC VTVM (or scope) to TP 103.
Set
audio
osc.
to
10
kHz
(+
50
Hz)
1
V.
Adjust
FL
104
for
minimum
meter
reading.
Set
audio
osc.
to
9
kHz
(+
50
Hz)
1
V.
Adjust
FL
105
for
minimum
meter
reading.
SIGNAL METER, AUTO STOP
R
208
controls
signal
strength
indication
and
auto
stop
level,
adjust
only
if
necessary,
to
correct
for
scan
stopping
on
excessively
weak
signals,
or
failure
to
stop
on
moderately
strong
ones.
NOTE:
When
finished,
lock
antenna
bar
adjustment
with
laquer
(nail
polish),
re-install
label.
12
TP101