Revox A76 Service Manual

Fig.
4.
18.-1
4Ja
Alignment
of
multiplex
filter
Test
equipment:
Test
generator,
frequency 94
MHz,
2
mV
o.c.v.,
modulated
with
stereo-modulator,
9
%
pilot
carrier
only
(
6.75
kHz
deviation
)
distortion
analyzer
or VTVM
38
kHz
band
pass
(see
fig.
4.2.-2)
4.18.1.
Tuner:
power switch
depressed
button STEREO
AUTOMATIC
(47)
depressed
Audio
output
controls
(
55
)
at
maximum
(
fully
cw
),
set
dial
pointer to 94
MHz
mark;
fine tune
to obtain
zero indi-
cation on
CENTRE
TUNING
meter
(44).
4.18.2.
Connect
38
kHz band
pass
between
tuner
output
(
56,
channel
1
or
channel
2
respectively)
and
distortion
analyzer
or
VTVM.
4.18.3.
Adjust
multiplex-filters
L503
and
L502
(for
channels 1
and
2
respectively)
to obtain
a
minimum
of
MPX-sIgnal (
less
than
1.5
mV)
(see
fig. 4.
18.-1
).
Fig.
4.19.-1
4.19.
Adjustment
for
minimum
stereo
crosstalk
Test
equipment:
Test
generator,
frequency 94
MHz,
2
mV
o.c.v.,
modulated
with
stereo-modulator,
deviation 40
kHz,
modulating
fre-
quency
1
kHz
( L
=
R),
pilot
carrier
9
%
(
deviation 6.75
kHz
)
distortion
analyzer
or VTVM
15
kHz
low pass
filter (see
fig.
4.2.-3)
4.19.1.
Tuner:
Power
switch
depressed
Button
STEREO
AUTOMATIC
(47)
depressed
Audio
output
controls
(55)
at
maximum
(fully
cw),
set
dial
pointer
to
94
MHz
mark;
fine
tune
to obtain
zero
indication
on the
CENTRE
TUNING
meter
(44).
4.19.2.
Connect
15
kHz
low-pass
between
tuner
output
(56,
channel
1
or
channel
2
respectively
)
and
distortion
analyzer
or
VTVM.
4.19.3.
Calibrate
distortion
analyzer
(or
VTVM)
for
0
dB
reference
deflection.
4.19.4.
Turn
off
modulation
on
channel
1
;
measure
crosstalk
on
channel 2
and
adjust
with
trimpot
P501
for
minimum
reading
(see
fig. 4.
19.-1
)
The
crosstalk
figure
must
exceed 40
dB.
4.19.5.
Turn
on
modulation
on
channel
1
and
turn
off
modulation
on
channel
2;
measure
crosstalk
from
channel
1
(
value
obtained
must be
better
than
40
dB).
17

Revox A76 Specifications

General

Brand	Revox
Model	A76
Category	Tuner
Language	English