Revox A76 Service Manual

Fig.
4J4.-1
Fig. 4.15.-1
4J4.
4.15.
Alignment
of
subcarrier
oscillator
(76
kHz) Alignment
of 19
kHz circuit
Test
equipment:
Test
equipment:
Test
generator,
frequency 94
MHz,
2
mV
o.c.v., no
modula-
tion, no pilot
signal
Digital
counter
for
a
frequency
of
38
kHz,
range
approx.
1 Vpp.
4.14.1.
Tuner:
Power switch
depressed,
set dial
pointer to the
94
MHz mark;
fine tune
to
obtain zero
indication on the
center tuning
meter
(44)
4.14.2.
Connect digital counter to test
point
8
(
see
fig.
4.
14.-1
)
4.14.3.
Tune
76
kHz oscillator
coil
L403
(see
fig. 4.
14.-1
).
Since the
square
wave frequency is
being measured
after the 1C
divider
(
1 :
2
),
this adjustment must
aim
for a frequency
of
38
kHz
±25
Hz)
Test
generator,
frequency
94
MHz,
2
mV o.c.v.,
modulated
with
stereo
modulator
9
%
pilot
carrier only
(
6.75
kHz
)
VTVM
AC
range to
read
3.5
V
(
+
0.5/-0.5 V).
4.15.1.
Tuner:
Power switch
depressed,
button
STEREO
AUTOMATIC
(47)
depressed
Set
dial
pointer to the
94
MHz
mark; fine tune to
obtain
zero indication
on
the
center
tuning meter
(44)
4.15.2.
Connect
VTVM to
test point
9
(see
fig.
4.15.-1
)
4.15.3.
Adjust L504
of
the 19
kHz circuit
to obtain a maximum,
VTVM reading 3.5
V (+
0.5/-0.5
V)
4.15.4.
Check
to
see
if light bulb STEREO
(45)
is illuminated.
4.15.5.
Turn
off
pilot
carrier, check
STEREO
indicator
light is now
off.
Test
operation
of
STEREO
indicator lamp which must
come
on
again with
6
%
pilot
carrier
(
deviation
4.5
kHz)

Revox A76 Specifications

General

Brand	Revox
Model	A76
Category	Tuner
Language	English