Teac A-450 - Service Manual

GENERAL INTRODUCTON
This
Service
Manual
is
provided
to
assist
service
technicians
throughout
the
world
to
properly
adjust,
repair
and
maintain
the
TEAC
A-450
Stereo
Cassette
Deck.
The
A-450
is
designed
to
be
used
with
a
high
quality
stereo
amplifier
system.
It
contains
many
of
the
standard
TEAC
features
such
as
selectable
BIAS
and
EQ,
DIN,
MIC,
LINE
Inputs,
PAUSE
Control,
Auto-End-Stop,
PEAK
LEVEL
Indicator,
Large
VU
Meters,
TAPE
RUN
Indicator,
etc.
In
addition
it
has
Dolby
NR
Circuitry,
DOLBY
FM/COPY
Facility,
FM
MPX
Filter,
MIC/LINE
Mixing,
Outer-rotor
Motor
and
unexcelled
Wow
and
Flutter
Specs.
If
adjustments
or
repairs
are
too
complicated
and
are
difficult
for
you
to
accomplish,
or
if
you
have
any
technical
questions,
please
contact
the
nearest
TEAC
Factory
Service
Department
or
write
directly
to
a
TEAC
office,
the
addresses
of
which
are
written
on
the back
cover.
This
manual
is
written
specifically
for
the
A-450
Model
distributed
in
the
U.S.A.
and
Canada.
However,
the
differences
in
models
distributed
elsewhere
is
very
small.
See
the chart
on
page
30
for
a
comparison
of
the
various
models.
NOTE
When
ordering
replacement
parts,
please
refer
to
the
PARTS
LIST
which
is
printed
separately
from
this
manual.
_)
*
Noise
reduction
circuit
made
under
license
from
Dolby
Laboratories
Inc.
The
word
“Dolby”
and
the
Double-D
symbol
are
trademarks
of
Dolby
Laboratories
Inc.
TEAC CORPORATION‘
51031682

Summary

GENERAL INTRODUCTION

SPECIFICATIONS & SERVICE DATA

TEST EQUIPMENT REQUIRED

TEAC TEST TAPE

Specific test tapes required for performance alignment and checks.

PARTIAL DIS-ASSEMBLY OF MAIN PARTS

CASE;FRONT PANEL

Procedure for removing and installing the cassette deck's case and front panel.

MOTOR

Steps for removing and replacing the motor assembly in the cassette deck.

CASSETTE HOLDER

Instructions for removing and disassembling the cassette holder mechanism.

HEAD;PINCH ROLLER

Guide for head and pinch roller assembly removal and replacement.

BRAKE BRACKET

Procedure for removing and disassembling the brake bracket assembly.

CAPSTAN DRIVE ASSY;DRIVE BELT

Steps for removing and replacing the capstan drive assembly and drive belt.

REEL TABLE

Instructions for removing and replacing the supply and take-up reel tables.

FAST WIND ROLLER ASSY

Procedure for removing and disassembling the fast wind roller assembly.

POWER TRANSFORMER

Steps for removing and replacing the unit's power transformer.

PLAY IDLER ASSY

Procedure for removing and disassembling the play idler assembly.

MECHANICAL CHECKS AND ADJUSTMENTS

PINCH ROLLER PRESSURE

How to check and adjust the pinch roller pressure specification.

TAKE-UP TORQUE

Procedure for measuring and adjusting the take-up torque specification.

FAST FORWARD TORQUE

Method for measuring and adjusting the fast forward torque specification.

REWIND TORQUE

Procedure for measuring and adjusting the rewind torque specification.

BRAKE TENSION

How to check and adjust the brake tension for proper operation.

TAPE SPEED;WOW AND FLUTTER

Procedure for checking and adjusting tape speed, wow, and flutter.

PARTS LOCATION

TOP VIEW

Diagram showing the location of parts when viewed from the top.

BOTTOM VIEW

Diagram showing the location of parts when viewed from the bottom.

LUBRICATION

MOTOR

Lubrication points and procedure for the motor assembly.

CAPSTAN ASSY

Lubrication points and procedure for the capstan assembly.

FLYWHEEL ASSY

Lubrication points and procedure for the flywheel assembly.

ELECTRICAL CHECKS AND ADJUSTMENTS

PLAYBACK PERFORMANCE

Alignments and checks for the playback section, including azimuth and output level.

VU METER CALIBRATION -PLAYBACK-

Steps to calibrate the VU meter during playback operation.

FREQUENCY RESPONSE -PLAYBACK-

How to check and adjust playback frequency response using test tapes.

SIGNAL TO NOISE RATIO -PLAYBACK-

Procedure for measuring the playback signal-to-noise ratio.

HEADPHONE OUTPUT LEVEL CHECKS

How to check the output level at the headphone jack.

MONITOR PERFORMANCE

Checks and adjustments related to the unit's monitor functions.

MINIMUM INPUT LEVEL CHECKS

Procedure for checking minimum input signal levels for various inputs.

SPECIFIED LINE CONTROL SETTING

How to set the line input controls to the specified levels.

DOLBY FM;COPY CAL CONTROL SETTING

Procedure for setting the Dolby FM/Copy calibration controls.

VUMETER CALIBRATION -RECORD-

Steps to calibrate the VU meter during recording operation.

LED PEAK LEVEL INDICATOR CALIBRATION

How to calibrate the LED peak level indicators.

DOLBY NR EFFECT MEASUREMENT

Procedure to measure the effectiveness of the Dolby NR system.

DOLBY FM COMPENSATOR EFFICIENCY CHECKS

How to check the efficiency of the Dolby FM Compensator circuit.

RECORDING PERFORMANCE

Procedures for adjusting recording performance parameters.

BIAS TRAP ADJUSTMENTS

How to adjust bias trap settings for optimal recording.

RECORD BIAS SETTING

Method for setting the recording bias level for different tape types.

RECORD LEVEL SETTING

Procedure for setting the recording signal level.

DISTORTION CHECKS

How to check and measure audio distortion during recording.

FREQUENCY RESPONSE -OVERALL-

Procedure for checking overall frequency response across tape types.

SIGNAL TO NOISE RATIO -OVERALL-

Method for measuring the overall signal-to-noise ratio.

ERASE EFFICIENCY

How to check the tape erase efficiency.

CHANNEL SEPARATION

Procedure to check and measure channel separation.

ADJACENT TRACK CROSSTALK MEASUREMENT

How to measure crosstalk between adjacent tracks on the tape.

ADJUSTMENT LOCATION

Diagrams showing the location of adjustment potentiometers and components.

LEVEL DIAGRAM

TROUBLE-SHOOTING

MODEL DIFFERENCES COMPARISON CHART

FUNCTIONAL DIFFERENCE TABLE

Table comparing functional differences between models.

ELECTRICAL ALIGNMENT SECTION (FOR ALL EXCEPT U.S.A.;CANADA MODELS)

Notes on electrical alignment differences for non-USA models.

FREQUENCY & VOLTAGE CONVERSION

Procedures for converting frequency and voltage settings for different regions.

PC BOARD SECTION (Diagram)

RECORD;PLAYBACK AMPLIFIER

Diagram of the record/playback amplifier circuit board.

POWER SUPPLY -U.S.A. (later models) -

Diagram for the USA model's power supply circuit.

POWER SUPPLY -All except U.S.A. (later models) -

Diagram for non-USA models' power supply circuit.

DOLBY B TYPE PROCESSOR

Diagram of the Dolby B Type Processor circuit.

TRIMMER RESISTORS -U.S.A. (later models) -

Diagram of trimmer resistors for USA models.

TRIMMER RESISTORS -All except U.S.A. (later models) -

Diagram of trimmer resistors for non-USA models.

TRIMMER RESISTORS -U.S.A. (later models) -

Diagram of trimmer resistors for USA models.

TRIMMER RESISTORS -All except U.S.A. (later models) -

Diagram of trimmer resistors for non-USA models.

DOLBY B TYPE PROCESSOR

Parts list for the Dolby B Type Processor section.

PARTS LIST

EXPLODED VIEWS AND PARTS LIST SECTION

Overview of sections detailing exploded views and parts.

PC BOARD SECTION (Diagram)

Diagrams illustrating the layout of various circuit boards.

PC BOARD SECTION (Parts List)

Detailed parts list for the circuit boards.

INCLUDED ACCESSORIES

List of included accessories with the unit.

ASSEMBLING HARDWARE CODING LIST

Guide to identifying screws, washers, and other hardware.

EXPLODED VIEWS -1-

First part of the exploded views illustrating component assembly.

EXPLODED VIEWS -2-

Second part of the exploded views illustrating component assembly.

PARTS LIST -2-

Second section of the parts list with component details.

EXPLODED VIEWS -3-

Third part of the exploded views illustrating component assembly.

PARTS LIST -3-

Third section of the parts list with component details.

EXPLODED VIEWS -4-

Fourth part of the exploded views illustrating component assembly.

PARTS LIST -4-

Fourth section of the parts list with component details.

PC BOARD SECTION (Parts List)

Parts list for the record/playback amplifier section.

ASSEMBLING HARDWARE CODING LIST

Teac A-450 Specifications

General

Type	Stereo Cassette Deck
Track System	4-track, 2-channel stereo
Tape Speed	4.8 cm/s
Heads	1 x record/playback, 1 x erase
Total Harmonic Distortion	1.0%
Output	0.41V (line)
Motor	DC servo motor
Tape Type	CrO2, Metal
Signal to Noise Ratio	58dB (dolby B)