Marantz PMD420 - Page 3

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MODEL PMD420/CP230 STEREO CASSETTE RECORDER
INTRODUCTION
This service manual
is
prepared for
use
by Authorized
Warranty Station and contains service information for
Marantz
Stereo
Cassette
Recorder.
Servicing information and voltage data included in this
manual
are
intended for
use
by the knowledgeable and ex-
perienced technician only. All instructions should
be
read
carefully. No attempt should
be
made to proceed without a
good understanding
of
the operation
of
the
Cassette
Recorder.
The parts list furnishes information by which replacement
parts
may
be
ordered from the Marantz Company. A simple
description is included for parts which
can
be
usually ob-
tained through local suppliers.
1.
SHOCK, FIRE HAZARD SERVICE TEST:
CAUTION:
After
servicjng this appliance and prior
to
re
•
turning
to
customer,
measure
the
res
istance between
either primary AC cord connector pins (with
unit
NOT
connected
to
AC mains and its Power switch ON),
and
the
face
or
front
Panel
of
product
and
controls
and
chassis
button.
Any
resistance measurement
less
than 1 Megohms should
cause
unit
to
be
repaired or corrected before AC power
is
applied, and verified before return
to
user/customer.
Ref.
UL
Standard NO. 1270.
Para
66. 3. D (Mandatory
Test after servicing Electrical Appliances, effective 7 • 1-83).
2.
P.W.
BOARDS
As can
be
seen from the circuit diagram, the chassis
of
your
Cassette
Recorder consists
of
the following units.
Each
unit
mounted
cm
a printed circuit board
is
described
within the square enclosed by a bold dotted line
on
the cir-
cuit diagram.
1. Rec/Play
Amp
.......
mounted on
P.W.
Board
P100
2.
Bias
OSC
...........
mounted on
P.W.
Board
P200
3.
Mic
Switch
.........
mounted on
P.W.
Board
P300
4.
L.E.D.
.
...........
mounted on
P.W.
Board
P400
5. Rec/Play
Sub
.
.......
mounted on
P.W.
Board
P500
6.
Mecha
Control
.......
mounted on
P.W.
Board
P600
7.
Control
Switch .
......
mounted on
P.W.
Board
P700
8.
Light
.............
mounted on
P.W.
Board
PSOO
9.
Mic
Mode
..........
mounted on
P.W.
Board
P900
3. TEST EQUIPMENT REQUIRED FOR
SERVICING
For measuring
or
checking
your
Cassette
Recorder, the
following instruments
and
materials
are
necessary.
•
VTVM
• Audio Oscillator
(AF
OSC)
• Attenuator
(600
n)
• Oscilloscope
• Bandpass Filter
(1
kHz)
•
IEC
A-Curve Filter
•
Wow
and
Flutte.r
Meter
• Torque Meter (Cassette Type)