Teac A-4070G Manuale utente

TEAC

CORPORATION

ay

A-4070G

®

STEREO

TAPE

DECK

SERVICE

MANUAL

ALSO

APPLICABLE

40706

SALES

OFFICE:

SHINJUKU

BLDG,

1-8-1,

NISH-SHINJUKU,

TOKYO

PHONE:

(03)

34351531

TEAC

CORPORATION

OF

AMERICA

7733

TELEGRAPH

ROAD,

MONTEBELLO,

CALIFORNIA

90640

PHONE:

(213)

7269303

TEAC

TONBAND-ANLAGEN

VERTRIEBS

GmbH

6200

WIESBADEN-ERBENHEIM,

EGERSTRASSE

2,

WEST

GERMANY

PHONE:

(06121)

74225-2322

8

TEAC

HONGKONG

LIMITED

51031092

8B

ROOM

NO.

1105

MELBOURNE

PLAZA,

33

QUEEN'S

ROAD,

HONG

KONG

PHONE:

2:20

27

PRINTED

IN

JAPAN

045

O03

1

GENERAL

DESCRIPTION

The

TEAC

A-4070G

is

a

2

channel,

4

track

tape

deck

capable

of

both

bi-directional

recording

and

playback,

The

A-4070G

employs

a

three

motor

mechanism,

solenoid

operated,

with

auto

reverse

in

either

direction,

automatic

repeat

and

continuous

play

capability.

The

basic

design

of

the

A-4070

is

highly

similar

to

that

of

the

A~4070G,

therefore

information

in

this

service

manual

may

be

ap-

plied

to

the

A-4070.

This

service

manual

provides

adjustment

and

alignment

procedures,

schematic

diagrams

and

parts

replacement

information

and

the

prop-

er

procedures

for

obtaining

necessary

repair

parts.

If

adjustments

or

repair

procedures

are

not

clear

or

seem

difficult

to

accomplish

or

should

you

desire

more

detailed

technical

informa-~

tion,

please

contact

your

nearest

TEAC

dealer,

TEAC

Corporation

or

affiliated

corporations,

address's

of

which

are

printed

in

this

manual.

INDEX

1.

GENERAL

DESCRIPTION

2.

SERVICE

DATA

3.

EQUIPMENT

REQUIRED

4.

PARTIAL

DISASSEMBLY

5.

HEAD

ALIGNMENT

-MECHANICAL-

6.

MEASUREMENT

AND

ADJUSTMENT

~MECHANICAL-

7.

MEASUREMENT

AND

ADJUSTMENT

-ELECTRICAL~

8.

PREVENTIVE

MAINTENANCE

9.

TROUBLE

SHOOTING

10.

PACKING

FOR

SHIPMENT

SCHEMATIC

DIAGRAMS

PRINTED

CIRCUIT

BOARD

AND

PARTS

LIST

EXPLODED

VIEW

AND

PARTS

LIST

MANUAL

CHANGES

MECHANICAL

2

SERVICE

DATA

Heads:

(Ferrite)

Tape

Width:

Tape

Speed:

Motors:

Wow

and

Flutter:

Fast

Winding

Time:

Operating

Position:

Power

Requirements:

Weight:

ELECTRICAL

Transistors:

Diodes:

Frequency

Response:

Equalization:

Input:

Bias

Frequency:

Signal

to

Noise

Ratio:

Stereo

Chan.

Cross

Talk:

Erase

Efficiency:

Separation:

Four

track

2

channel

stereophonic

Erase/Record

combination

head

x2;

Erase

section,

1.8k2/100kHz,

erase

current

approx.

30mA

Record

section,

95Q2/1kHz,

bias

current

approx.

25mA

4.7k2/100kHz,

signal

current

approx.

400Hz

200yA

Playback

x2;

1.2kQ/1kHz

-66dB

Standard

1/4

inch

tape

7-1/2ips

and

3-3/4ips

(40.5%)

4/8-pole

dual

speed

hysteresis

synchronous

motor

for

capstan

drive

Two

6-pole

eddy

current

motors

for

reel

drive

0.06%

at

7-1/2ips

0.09%

at

3-3/4ips

Wow

and

flutter

measured

according

to

weighted

NAB

standard

using

TEAC

test

tape.

Approx.

120

seconds

or

less

for

1200

feet

Horizontal

or

vertical

100/117/200/220/240V

AC

50/60Hz

125W

51

lbs

(23kg)

net

2SC733BL

x2

2SA494

x2

250733

x14

2SC971

x2

2SC1LOOOBL

x12

FR2-02

x3

FR2-10

x2

SIBO2-B

x1

FR2-08

x3

FR2-06

x7

Overall

from

recording

INPUT

to

playback

OUTPUT

using

SCOTCH

#203

tape

7-1/2ips,

+3dB

30Hz

v20kHz

3-3/4ips,

+3dB

40Hzv10kHz

NAB

equalization

7-1/2ips

50yu

sec

MIC

0.3mV

(-70dB)

LINE

0.1V

(-18dB)

100kHz

push-pull

oscillator

7-1/2ips

48dB

or

higher

3-3/4ips

46dB

or

higher

at

playback

to

unweighted

noise

45dB

channel

to

channel

at

1kHz

35dB

adjacent

track

at

100Hz

70dB

or

more

at

7-1/2ips

3-3/4ips

90n

sec

These

specifications

are

indispensable

information

and

are

required

to

service

the

equipment

properly.

They

may

differ

slightly

from

those

printed

in

the

advertising

brochures

or

the

operation

manual.

3

EQUIPMENT

REQUIRED

FOR

MECHANICAL

MEASUREMENT

————————__________

eee

SPRING

SCALE:

TEST

TAPE:

FLUTTER

METER:

DIGITAL

FREQ.

COUNTER:

TOOLS:

0.4

kilo-grams

(08

lbs)

#5086025000

0.300

grams

(0°10

oz)

#5086026000

TEAC

YTT-2003

(7-1/2ips)

TEAC

YTT-2002

(3-3/4ips)

Meguro

Model

MK665B

(preferred)

or

Sentinel

FL-3D-1

Capable

of

O

to

5kHz

indication

General,

2mm

nut

driver

#5086014000

Hex

head,

allen

wrench

#5086021000

TEAC

TEST

TAPE

Fig.

3-l

Spring

Scale,

and

TEAC

Test

Tape

FOR

ELECTRICAL

MEASUREMENT

TEST

TAPE:

EMPTY

REEL:

TEST

SET:

BAND

PASS

FILTER:

AC/DC

VIVM:

RESISTOR:

OSCILLOSCOPE:

Fig.

3-2

TEAC

M-826A

TEAC

YTT-1003

for

7-1/2ips

TEAC

YTT-1002

for

3-3/4ips

SCOTCH

203

and

150

for

test

recording

TEAC

RE~702

(2"

hub)

TEAC

RE-701

(4"

hub)

TEAC

M~826A

test

set

TEAC

M-206A

(1kHz)

General

purpose

Non

inductive

type

82/1W

General

purpose

NOTE

Use

of

the

TEAC

M-826A

test

set

is

rec-

ommended.

This

set

incorporates

an

AC

VTIVM,

Audio

Oscillator,

Channel

Select~

ing

switch,

Variable

Attenuator,

Monzitor

Speaker

and

Cables.

TEAC

M-826A

measures

the

RMS

value

of

the

Voltage

(OdB=0.775V).

Characteristics

of

this

test

set

are

similar

to

the

stan-

dard

VU-meter.

4

PARTIAL

DISASSEMBLY

REMOVING

THE

EQUIPMENT

FROM

CASE

Case

should

only

be

removed

to

perform

major

maintenance.

1.

Lay

tape

deck,

face

down

on

a

soft

mat.

2.

Remove

the

two

(2}

screws

at

the

top

of

the

case,

remove

the

four

(4)

screws

on

rear

of

case.

Carefully

lift

case

from

mechanism.

7%

(200mm)

=

Dimensions

173449

(456mm)

(awaon*%.s1

(wmgey)

2621

FRONT

PANEL

REMOVAL

I

ul

&

WN

6.

7.

Place

the

A-4070G

on

its

back,

with

the

front

panel

assy

face

up

and

the

bottom

of

the

deck

towards

you.

Remove

the

head

housing

assy.

Remove

both

tape

tension

arms.

Remove

knobs.

Remove

the

ten

(10)

cross-point

screws

from

the

front

panels.

NOTE

Two

screws

are

immediately

above

the

tape

head

mechanism.

Lift

off

the

control

panel

assy.

Lift

off

the

front

panel

assy.

AMPLIFIER

ASSEMBLY

ACCESS

The

A-4070G

is

equipped

with

a

removable

amplifier

assembly.

By

removing

the

six

screws

that

secure

the

amplifier

to

the

bottom

of

the

chassis,

you

can

easily

swing

out

the

amplifier

for

maintenance.

Most

of

the

replacement

components

are

completely

accessible.

If

amplifier

assy

maintenance

is

necessary,

follow

these

steps:

1.

2.

AMPLIFIER

ASSEMBLY

ACCESS

Complete

all

steps

in

front

panel

removal.

Remove

six

(6)

cross-point

screws

from

the

sides

of

the

bottom

panel.

NOTE

Three lower

screws

are

holding

the

cover

panel

over

the

PC

boards.

These

need

not

be

removed.

Access

slots

are

provided.

Grasp

the

control

shafts

and

gently

swing

the

amplifier

assy

dow

towards

you.

Two

screws

on

the

lower

sides

act

as

a

hinge

for

the

assy.

To

re-~assemble,

reverse

the

above

procedure.

CAUTION

When

closing

the

amplifier

assy,

closely

observe

the

wires

leading

to

the

right-channel

VU

meter

lamp

socket.

PLAYBACK

HEAD

REPLACEMENT

The

playback

heads

have

a

detachable

shielded

housing,

see

the

exploded

view

illustration

for

disassembly

instructions.

omm(

o-

Ot

(6600

e-

@

M-0286

Fig.

4-1

Individual

Heads

CAPSTAN

MOTOR

REMOVAL

1.

With

front

panel

removed,

remove

4

capstan

motor

mounting

screws.

2.

Unsolder

the

6

wires

connecting

the

capstan

motor.

(Carefully

note

the

wire

locations

and

color

codes).

NOTE

After

motor

replacement,

check

position

of

capstan

pulley

on

shaft

for

proper

alignment

with

belt

guide.

REEL

MOTOR

REMOVAL

1.

Disconnect

oiling

tubes

at

motor

housing.

2.

Loosen

2

set

screws

securing

the

reel

table

assembly,

remove

reel

table.

3.

Remove

the

four

screws

securing

motor

to

chassis,

unsolder

the

six

wires

connecting

the

motor.

NOTE

Reel

motor

assemblies

are

mirror

images

of

each

other,

these

as-—

semblies

are

not

interchangeable.

Fig.

4-3

Reel

Motor

Removal

DISASSEMBLY

OF

CAPSTAN/HEAD

MOUNT

AREA

1.

2<

Remove

the

VU

meter

holder.

Remove

four

button

head

Philips

screws

securing

the

head

base

plate.

Base

plate

may

now

be

lifted

forward

to

accomplish

belt

replacement.

In

order

to

replace

the

capstan

assembly,

the

slide

base

assembly

must

first

be

removed.

1.

2%

Remove

the

L

&

R

lower

head

protectors.

Remove

pinch

roller.

Remove

lower

screw

and

nylon

inserts

from

slide

base

assembly.

(located

below

the

pinch

roller

shaft

housing).

.

Disconnect

slide

base

assembly

coil

spring.

.

Remove

the

screw

in

one

of

the

head

PC

board

brackets,

lift

PC

board

from

bracket

thus

freeing

the

lifter

spring

bracket.

.

Remove

screw

and

nylon

inserts

from

lifter

spring

bracket.

Slide

base

assembly

may

now

be

removed

exposing

the

capstan

assembly

mounting

screws.

Fig.

4-4

Capstan

Assy

and

Head

Mount

Removal

REEL

MOTOR

C801

POWER

TRANSFORMER

REEL

MOTOR

K3

K2

Kl

K7

K6

K5

ee

K4

K8

Bo?

ewpinions

SY

FREQUENCY

SELECTOR

LEVER

-~~

PULL

60Hz

FREQUENCY

SELECTOR

SWITCH

-4

NOTE

K3

REV.

RELAY

R802

BACK

TENSION

K2

REV.

RELAY

R803

TAPE

0.5

MIL

(THIN)

Kl

PLAY

RELAY

R801

TAKE-UP

K7

REPEAT

SENSING

RELAY

K1l

F.

FWD

RELAY

K6

REV.

SENSING

RELAY

K10

SPEED

RELAY

K5

FAST

RELAY

K12

MUTING

RELAY

K4

DELAY

RELAY

K8

SHUT

OFF

RELAY

TAPE

TRANSPORT

PARTS

LOCATION

—

REAR—

R803

R802

R801

Kil

K1O

K12

R804

C813

CAPSTAN

MOTOR

C803/805

M-0284

5

HEAD

ALIGNMENT

—MECHANICAL—

NOTE

Head

alignment

is

adjusted

at

the

factory

to

very

critical

tol-

erances.

Normally

HEAD

ASSEMBLY

replacement

will

require

only

minor

alingments

or

adjustments.

Complete

readjustment

should

only

be

necessary

after

an

individual

head

is

replaced.

The

adjustments

are

made

as

follows:

FORWARD

SIDE

@ERASE/RECORD

COMBINATION

HEAD:

The

record

head

pole

should

be

above

the

edge

of

a

threaded

tape

by

the

width

of

thin

pencil

line.

NOTE:

Erase

head

should

be

heavy

pencil

line.

@PLAYBACK

HEAD:

The

playback

head

pole

should

be

even

with

the

top

of

a

threaded

tape.

e

HEIGHT

ADJ

.

SCREW

e

m)

e

AZIMUTH

ADJ

.

SCREW

Fig.

5-1

Head

Alignment

and

Adjustment

sede

Seco

es

oe

|

M-0287

ERASE/RECORD

PLAYBACK

ERASE

/RECORD

COMBINATION

cabaeiea

COMBINATION

REVERSE

SIDE

@ERASE/RECORD

COMBINATION

HEAD:

The

record

head

pole

should

be

bottom

the

edge

of

a

threaded

tape

by

the

width

of

thin

pencil

line.

NOTE:

Erase

head

should

be

heavy

pencil

line.

@PLAYBACK

HEAD:

The

pole

of

the

playback

head

should

be

even

with

t

he

bottom

of

a

threaded

tape.

NOTE

Azimuth

adjustments

are

given

in

the

section

on

MEASUREMENT

AND

ADJUSTMENT

-ELECTRICAL-

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