Marantz 4415 - INTRODUCTION TO MARANTZ 4415 RECEIVER; SERVICE NOTES; AM TUNER OPERATION AND TROUBLESHOOTING

INTRODUCTION
This
service
manual
was
prepared
for
use
by
Authorized
Warranty
Stations
and
contains
service
information
for
Marantz
Model
4415
Quadradial
4
Receiver.
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
receiver.
|
The
parts
list
furnish
information
by
which
replacement
part
may
be
ordered
from
the
Marantz
Company.
A
simple
description
is
included
for
parts
which
can
be
usually
be
obtained
through
local
suppliers.
1. SERVICE NOTES
As
can
be
seen
from
the
circuit
diagram,
the
chassis
of
Model
4415
consists
of
following
units.
Each
unit
mounted
on
a
printed
circuit
board
is
described
within
the
square
enclosed
by
a
bold
dotted
Jine
on
the
circuit
diagram.
1
EM
and
AM
TUNE!
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028
weed
ieee
ead
es
mounted
on
P.C.
Board,
P100
2
PHONO
-AMDINIGr
2ic2~
sear
ee
a
graee
tne
ee
eee
Une
acaba
mounted
on
P.C.
Board,
P300
9
Tone
AMINE
3:
bea
che
cee
kal
eee
Sb
eA
Rees
See
mounted
on
P.C.
Board,
P400
A
MareWiaticuUnt:
s2s65.0
tisk
ca
eat
Ba
ome
ee
ee
Cee
bea
mounted
on
P.C.
Board,
P500
5
Power
Amplifier
.2cs4.c0neke
eee
ea
eee
aaa
mounted
on
P.C.
Board,
P600
6.
Loudness
and
Speaker
Switch
Unit
.......
0.0...
ee
ee
eee
mounted
on
P.C.
Board,
P700
7
Tone
GOntrol
URIt-
42.094
siaee
tee
ete
hee
eas
ea
iS
mounted
on
P.C.
Board,
P750
8.
POWerSUDDIV:
#a44ckatutetdue
pee
a
HO
ees
eed
mounted
on
P.C.
Board,
P800
9:
Balance
Control
Unit.
.<s244oo644
654s
eG
eee
eee
mounted
on
P.C.
Board,
P900
10
PiltemUGit
x24
ee
are
4
eet
Ge
eae
Annee
ela
}
oe
mounted
on
P.C.
Board,
P950
11:
Indicator
LAMDS:
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cee
toe
seit
eeeda
Ss
mounted
on
P.C.
Board,
P980
2.
AM
TUNER
|
All
components
except
ferrite
bar
antenna
are
mounted
on
a
printed
circuit
board
P100.
The
AM
signals
induced
in
a
ferrite
bar
antenna
are
applied
to
the
base
of
converter
transistor
H113
through
a
capacitor
of
C171,
while
the
local
oscillator
voltage
is
injected
to
the
emitter
of
H113
through
a
capacitor
C172.
Both
AM
signals
and
oscillating
voltage
are
mixed
at
the
base-emitter
junction
and
converted
into
455KHz
intermediate
frequency.
The
resulting
IF
signal
is
applied
to
the
first
IF
transformer
L116
consisting
of
one
ceramic
filter
and
two
tuned
circuits.
The
output
of
L116
is
led
to
the
transistor
H104
which
in
turn
apply
its
output
to
the
transistor
of
next
stage
H105.
The
fully
amplified
IF
output
is
then
applied
to
the
diode
H123
ta
detect
audible
signal
through
the
detector
transformer
L117.
The
detected
audio
signal
is
filterec
and
the
final
audio
output
is
obtained
from
pin
terminal
J118
and
applied
to
the
audio
amplifier
section through
the
selector
switch.
The
DC
component
of
the
detected
IF
signal
is
used
as
a
AGC
voltage
to
control
emitter
current
of
H104
through
the
resistor
R185.
A
part
of
IF
signal
output
is
also
applied
to
the
diode
H124
through
a
capacitor
C180
and
rectified
to
obtain
DC
current
for
energizing
the
signa
strength
meter
MOOY.
1.1 Suggestions for AM Tuner Trouble Shooting
Check
for
broken
AM
bar
antenna,
next
try
to
tune
station
by
rotating
fly-wheel
tuning
knob
slowly
and
observe
the
signal
strength
meter
whether
it
deflects
or
not.
If
the
signal
strength
meter
gives
a
deflection
at
several
frequencies
received,
no
failure
may
exist
in
the
stages
at
least
preceding
final
IF
transformer
L117.
Next
connect
a
oscilloscope
to
the
pin
terminal
J118
anc
check
for
audio
signals
with
the
tuning
meter
deflected.
if
the
signal
strength
meter
does
not
deflect,
check
the
local
oscillator
circuit.
Normal
oscillating
voltage
at
the
hot
end
of
the
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