NAD 7130 Service Manual

detector
coarse
adjustment
(OPTIONAL, NEEDED
ONLY
IF
DETECTOR
WAS
REPAIRED).
1.
Reduce
sweep
modulation
level
to
+/-
75
kHz
and
set
input
level
to
300
juV.
2.
Adjust
FM
generator
frequency
so
that
both
legs of the
inverted
U-shaped
curve
are
equally
high
on the
dis-
play.
The
curve
should be
almost
perfectly
symmetrical.
3
Disconnect
detectorprobe
from
tuner
and
oscilloscope.
Connect
either of
the
tape
rec.
outputs
to
the
oscillo-
scope.
4.
Adjust
IFT
1
primary
(closest
to
the
rear of
unit)
to
maximum
curveheight
and IFT
1
secondary
(closest
to
the
front
of
unit) to
minimum
curveheight
and straightest
possible
line.
Go back
and
forth between
primary
and
secondary
till
both are
peaked,
NOTE:
Both
the
cores
should
be
within 1 .5
mm
from
the top
of
the
form.
DETECTOR
ALIGNMENTS
(FINAL)
1
Disconnect
detectorprobe
and
connect
tape
rec. outputs to
VTVM's,
oscilloscope
and
distortion
analyzer.
2.
Switch
stereo
generator to
1
kHz
100%
(+/- 75
kHz)
mono
modulation
and
oscilloscope
to
normal
internal
sweep
0.2 mS
and
0.5
V/cm
sensitivity.
3.
Det
ector
reference
frequency
Reduce
FM
generator
output
level
while
monitoring THD
from
left
channel.
When
THD
increases
to 3
%,
fine
tune
the
FM
generator
frequency
to
minimum THD.
Reduce
FM
generator
output
level
and
fine
tune till
no
reduction
in
the
3%
THD
can be
achieved
by
fine tuning.
Use
this
frequency
for all
the
following
detector,
MPX
and DYN
SEP
adjustments.
NOTE:
The
typical
input level
for
this
3%
THD
should be
1.6
/iV to
2.3
/iV.
This is
done
only
to
“lineup"
the
frequency
from the
generator to
the
tuner's
frequency.
If IHF
usable
sensitivity
(-30
dB
THD+N
=
3.16%
THD+
N) is
to
be
verified,
a
proper
IHF
band-
passfilter must be
used.
4.
Connect
DMM
across TP
2
(negative)
and TP
1
(positive). Set
FM
generator
output
level
to
1000
/iV.
5.
Adjust
IFT
1
primary (closest
to
the
rear
of unit)
for 0 V
on DMM
TOLERANCE
+/-
50
mV
6.
Adjust
IFT
1
secondary
(closest to
the
front of unit)
for lowest THD
SPECIFICATION
less
than 0.1%.
7.
Repeat
steps
3-5
and
6
till
no
further
improvements.
Record
the
DMM's
final reading
for use
later
in
the
adjustment.
autosearch
LEVEL
1.
Connect
DMM
between
1C
2
pin
12
and
ground.
2
Increase
FM
generator
level
upwards
from
0
and
adjust VR 1
so that
DMM
reading goes
from
0
V to
approxi-
mately
4.8 V at
10
/iV.
TOLERANCE
+/-
2
juV
STEREO
DECODER,
MPX
FILTERS.
1.
vco
Connect
a
frequency
counter
between 1C
6
pin
11
and ground.
2.
Set
FM
generator
to
1000
juV
output
and
no
modulation.
3.
Adjust
VR
3
for
a
19000 Hz
reading
on the
counter.
TOLERANCE
+/-
100
Hz
4.
Disconnect
frequency
counter and
press
DYN
SEP
defeat switch
(in).
5.
Stereo
switch
threshold.
Modulate
FM
generator 1
kHz
45%
left
only
plus 1 9 k Hz pilot
8
-
10
%.
6.
Increase
FM
generator
level upwards
from 0
and
adjust
VR
2
so that
stereo light
turns
on and
audio
outputs
as
watched
on VTVM and
oscilloscope,
switches
to
one
channel
only
at
10
/zV
input
level.
TOLERANCE +5
juV
When turning
input
level
down the
unit will switch
into
mono
at a
lower level,
typically 5
—
7
NOTE:

NAD 7130 Specifications

General

Brand	NAD
Model	7130
Category	Stereo Receiver
Language	English