Revox B150 Service Manual

5TUDER R^OX
B250/B250-S/B150
E4/1
E
L
E
CT
R IC AL
HEftSUREME
N
T
S„ft
ND
'g|jgiiSTME]ii^
1
1..11.ZI
4 .
1
MEASURING
INSTRUMENTS
AND IQDJLS
CAUTION!
Shock
hazard
when
the
ampli-fier
is
open.
Certain
parts
are
energized
with
line
voltage.
AF
voltmeter
Digital
voltmeter
Oscilloscope
Part
No.
46020
On
request
On
request
4.2
PREPARATORY
STEPS
Fig.4.1
Remove
the top
cover
(Section
2.2.1)
4.3 O
PERATING
VOLTAGES
Operating
voltages
ot the
POWER
AMPLIFIERS
4.5
BRIGHTN
E SS
CONTROL
OF
THE
VF
DISPLAY,.,
The
electronics
that
responds
to
the
brightness
o-f
the
ambient
light
can
be
aligned
with
the
two
trimmer
potentiometers
R67
and
R70:
Voltage
Pin
Connector
L
channel
Connector
R
channel
53
V
1
yel 1 ow
violet
53 V
2
yel
1
ow
vi ol
et
42 V
3
orange
red
42
V
4
orange
red
0
V
4
grey
black
The
voltages
must
be
measured
individually
tor both
output
stages
because
there
are
separate
transtormer
windings
tor
each
channel-
4.4
QUIESCENT
CURRE
N T
Switch on
the
amplitier;
the
quiescent
current
should be
measured
at
operating
iBmEs.rj§.fe4.CS.-
This
temperature
is
reached
approsi.
10
minutes
atter
power
ON.
Connect
the
AF
voltmeter
to
the
POWER
AMPLIFIERS
TPl
—
>
+
TP2
—
>
-
Adjust
the
potentiometer
RA91
to
obtain
a
voltage
reading
o-f 1
mV.
Repeat the
same
adjustment
-for
the
second output
stage.
Detach
the
-front
panel
so
that
the
two
potentiometers
become
accessible.
Connect
the
oscilloscope
to
ATPl
(IC9
Pin6);
Horizontals 50
ps/div.
Verticals 1
V/div.
Fig. 4.2
Turn
the
potentiometer
R67
counterclockwise
to
the
minimum.
In
complete
darkness
adjust
R70 to
a
pulse
duty
factor
of 9;1.
Position
a
yellow
light
source
with an
intensity
of
20
Lu>:
in
front
of
the
left-hand
panel
near
the
photoresistor.
Adjust
R67
to a
pulse duty
factor
of 4sl.
Increase
the
light
intensity
to
200
Lum;
the
pulse
duty
factor
should
decrease
to
less
than
1:9.

Revox B150 Specifications

General

Brand	Revox
Model	B150
Category	Amplifier
Language	English