Marantz 4070 - Introduction and Service Notes; Service Notes Details; Selector Switch Functionality; Mode Switch Operation Guide

1. INTRODUCTION
This
service
manual
was
prepared
for
use
by
Authorized
Warranty
Stations
and
contains
service
information
for
Marantz
Model
4070 Solid-State
Quadradial
Console
Amplifier.
Servicing
information
and
voltage
data
included
in
this
manual
are
intended
for
use
by
the
knowledgeable
and experienced
technician
only.
All
instruction
should
be
read carefully.
No
attempt
should
be
made to
proceed
without
a
good
understanding
of the
operation
in
the
circuits.
The parts lists furnish information by which replacement part may be ordered from the
Marantz
Company.
A
simple
description
is
included
for
parts
which
can
usually
be
obtained
through local suppliers.
2. SERVICE NOTES
As
can
be
seen
from
the
circuit
diagram
the
chassis
of
Model
4070
consists
of
the
following
units. Each
unit mounted
on a
printed
circuit
board
is
described
within
the
square
enclosed
by
a
bold
dotted line
on the
circuit
diagram.
1. Phono Equalizer Amplifier .............cccceeeeecsseeseeeeceeseres mounted on P.W. Board, P400
2. Tone Amplifier .....c...ccessescccsssecessccceeecssceceenceseeeenenes mounted on P.W. Board, PEO1
3.
Power
Amplifier
oo...
....cccccccssssseesssceesessecceceesseeceesesereeees
mounted
on
P.W.
Board,
P700
4, Loudness, Tape Mon., High Filter,
Main-Remote Speaker Switch Unit ......... ee mounted on P.W. Board, PSO1.
5.
Power
Supply,
Vari-Matrix,
Buffer
Amplifier
Unit
......
mounted
on
P.W.
Board,
P800
6. Tone & Balance Variable Resistor Unit .................00000 mounted on P.W. Board, PF01
3. SELECTOR SWITCH
Signals
from
the
PHONO
jacks
are
applied
to
the
phono-amplifiers
and
equalized
to
match
the
RIAA
curve
for
flat
frequency
response.
The
outputs
of
the
phono-amplifiers
and
signals
from
the
TUNER,
TAPE
2
and
CD-4/AUX
jacks
are
led
to
the
SELECTOR
switch,
S001.
The
SELECTOR
switch
selects
one
set
of
signals
from
PHONO,
TUNER,
TAPE
2
and
CD-4/AUX
jacks
and
sends
them
to
the
MONITOR
switch
and
TAPE
1
MON
OUT
jacks.
The
selected
signals
are
then
applied
to
the
MODE
switch,
S002.
PHONO
and
TUNER
jacks
are
for
2-channel
input
signals,
that
is
stereo
signals.
CD-4/AUX,
TAPE
2,
TAPE
1
MON
IN
and
TAPE
1
MON
OUT
jacks
are
4-channel,
that
is
quadraphonic,
signals.
4. MODE SWITCH
MODE
switch
S002
has
positions
of
MONO,
2
CH,
DISCRETE,
VARI-MATRIX,
and
SQ
DECODER.
In
the
MONO
position
all
input
signals
are
mixed
together
and
delivered
to
all
four
channels.
In
the
2
CH
position
stereo
signals
are
directly
routed
to
the
pair
of
front
left
(LF)
and
front
right
(RF)
channels;
the
same
signals
at
the
LF
and
RF
channels
are
fed
to
the
rear
left
(LR)
and
rear
right
(RR)
channels,
respectively.
When
quadraphonic
signals
are
applied
to
the
input
terminals,
the
LF
and
LR
signals
and
RF
and
RR
signals
are
separately
added,
thus
the
(LF
+
LR)
signal
is
delivered
to
the
LF
and
LR
channels
and
the
(RF
+
RR)
signal
is
delivered
to
the
RF and RR
channels.
In
the
DISCRETE
position
the
quadraphonic
input
signals
are
separately
routed
as
4-channel
stereophonic
signals
to
each
channel.
At
this
position,
for
ordinary
stereo
input
signals,
neither
LR
nor
RR
channels
no
signal
to
carry.
In
the
VARI-MATRIX
position,
2-channel
stereo
input
signals
are
converted
into
quadra-
phonic
signals
through
the
vari-matrix
circuit;
the
input
right
and
left
channe’
signals
are
fed
directly
to
the
LF
and
RF
channels,
while
the
signals
to
the
LR
and
RR
channels
are
synthesized
from
the
2-channel
input
signals
under
the
control
of
the
DIMENSION
control.