Revox A76 Service Manual

Fig.
43.-1
Fig.
4.4-2
It
is absolutely
essential to
check the supply
voltages
before
attempting any alignment
of the
tuner.
43
.
Checking of supply voltages
Tuner switched
on
(
power switch only,
no other button
de-
pressed);
voltage readings against chassis.
Current
consumption on
220
V
line:
65
mA
red:
+23
V (+
1
/—
0
V) 1
Ripple voltage less than
blu:
-
23 V
(+0
/-I V)
|1
mV
org:
+
6.2 V
(+
0.5/-0.2
V)
grn:
-
6.2
V
(+
0.2/-0.5
V)
vio:
+
4 V
(+0.8/-0.5
V)
C
134
(V2))
C
125
(V1)j
-15
V
(±0,8
V)
44
.
Tuning
of IF
filters
Important:
All
tuning slugs
are to
be
positioned so as
to pro-
duce
a maximum when turned to
their upper
setting.
(
see
fig.
4
4.-1
)
correct
incorrect
Test
equipment
Test
generator
frequency 10.7
MHz
(
+
20
kHz
),
63
mV
o.c.v.
no
modulation
IF
matching
network (see
fig.
4.2.-1
)
VTVM wit RF
probe, range
to read
0.9
V
(+0.2/—
0.1 V)
4.4.1.
Tuner:
power
switch depressed
4.4.2.
Remove
spade lug AB
1
(
test point
1
)
and
connect
IF
matching
network.
(
On
tuners with the
new RF
section
1.076.160-1 the
—23
V
connection is
not required).
44.3.
Connect
RF probe
of VTVM to
testpoint
2
(see
fig.
4.4.-2
)
44.4.
Adjust slugs
of
the
IF filters FT 201
to FT 208
to
obtain
an exact
maximum
voltage
reading on the
VTVM. This
tuning
procedure must be
repeated until
no
improvement
can be
achieved any more.
4.4.5.
Immediately
following upon the
tuning
of
the
IF
filters,
the
centre
tuning
discriminator
must be
aligned
as
described
under section
4.5
(
any
frequency drift
of
the
test
generator
would lead to
an erroneous
adjustment).
Important: do
not alter the
frequency
setting of
the
test
generator.
10

Revox A76 Specifications

General

Brand	Revox
Model	A76
Category	Tuner
Language	English