Sony TA-E88 User manual

TA-E88

(Panel:

Silver)

AEP

Medel

TA-E88B

(Panel:

Black).

AEP

Medel

UK

Medel

SPECIFICATIONS

GENERAL

Power

Requirements:

0dB=0.775

V

|

240

V

ac,

50/60

Hz

(UK)

Outputs:

220

V

ac,

50/60

Hz

(AEP)

a

=

Power

|

Voltage

Impedance

Consumption:

22

W

REC

OUT

1,2

|

150

mV

(—14.5

dB)

(max.

15

V)

1kQ

Dimensions:

Approx.

480

(w)

x

80

(h)

x

370

(d)

mm

OUTPUT

1,2

1.5

V

(5.5

dB)

(max.

15

V)

100

2

19

(w)

x

3.34

(h)

x

14

x

(d)

inches

Including

projecting

parts

and

controls

Approx.

9.4

kg,

20

Ib

12

oz

(net)

9.7

kg,

21

Ib

7

oz

(with

shipping

carton)

Harmonic

Distortion:

Less

than

0.002

%

at

10

V

output

IM

Distortion:

Less

than

0.002

%

at

10

V

output

(6O0Hz

:

7kHz=4:

1)

Weight:

Frequency

Response:

PHONO

1,2

RIAA

equalization

curve

+0.2

dB

TUNER,

AUX

0

'

=

+

TAPE

1,2

)

de

—

500

kHz

ty

dB

Filters:

LOW

12

dB/oct.

below

15

Hz

Less

than

6

nV

(weighting

network

A,

IHF

with

ATTENUATOR

set

to

min

imum,

FILTERs

to

OFF}

Residual

Noise:

AMPLIFIER

SECTION

Inputs:

Rae

|

.

Maximum

input

S/N

(weighting

network,

I

|

Sensitivity

mpedance

Capacitance

capability

(1

kHz)

|

input

level)

|

PHONO

1

2.5

mV

(—50

dB)

50

kQ

100

pF

250

mV

(—10

dB)

88

dB

{A,

2.5

mV)

Sn

at

se

i

ea ae

Pee

ee

Ones

oh

eee

i

ein

elle

ee

er

eg

2

|

HEAD

AMP

0.125

mV

(—76

dB)

252:/1002

-

12.5

mV

(—36

dB)

80

dB

(A,

0.2

mV)

10

kQ—-100

k2j100

pF—S00

pel

HON

Vv

{+

i

—

PHONO

2

2.5

mV

{(—50

dB)

(10

k®

steps)

|

(100

pF

steps)

250

mV

{-10

dB)

88

dB

(A,

2.5

mV)

|.

—--~.~--}

---

ae

no

Sani

a)

kar

ated

td

cies

hatchet

Lo

os

a

eesti

vale

>

marae

oie

cs

ae

ad

Se

ee

wa

a

we

HEAD

AMP

0.125

mV

(—76

48)

|

2522/1002

-

/12.5

mV

(—36

dB)

80

dB

(A,

0.2

mV)

TUNER,

AUX

TAPE

1.2

150

mV

(—14.5

dB)

50

kQ

_

105

dB

(A,

150

mV)

SAFETY-RELATED

COMPONENT.

WARNING

COMPONENTS

IDENTIFIED

BY

SHADING.

AND

A

MARK

ON.

THE

SCHEMATIC

DIAGRAMS,

EXPLODED

VIEWS

AND

IN

THE

PARTS.

LIST

ARE

CRITICAL

TO

SAFE

OPERATION.

REPLACE

THESE

COMPONENTS

WITH

SONY

PARTS

WHOSE

PART

NUMBERS

APPEAR

AS

SHOWN.

IN

THIS

MANUAL

OR

IN

SUPPLEMENTS

PUBLISHED

BY

SONY.

MODEL

IDENTIFICATION

Specification

Label

SONY,

STEREO

PREAMPLIFIER

MODEL

NO

TA—E88B

SONY,

STEREO

PREAMPLIFIER

MODEL

NO

TA—E88

SERIAL

NO

SERIAL.

NO

6

OO

AC

220V..°~2

AC.

220V

oa

50/60Hz

.22W

50/60Hz

22W

|

MADE

IN

JAPAN

MADE

IN

JAPAN

TA-E88

(AEP

Model)

TA-E88B

(AEP

Model)

SONY.

STEREO

PREAMPLIFIER

MODEL

NO

TA—E£88B

SERIAL

NO

AC

240V

0

~~

50/60Hz

22W

MADE

IN

JAPAN

TA-E88B

(UK

Medel)

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2

HEAD

AMP

SUPPLY

Q751~

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POWER

SUPPLY

Ql

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RELAY

DRIVE

AMP

Q901-

904

1

'

7

B-(2)

GND

BH2)

B-()

GND

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|

(MUTING)

q883/883-vVl

‘TA-E88/E88B

1-2,

CIRCUIT

DISCRIPTION

4-2-1.

Phono

1

and

Phono

2

Input

Circuits

The

TA-E88/E88B

is

equipped

with

two

phono

inputs

—

PHONO

|

and

PHONO

2.

PHONO

1

@

When

using

high

impedance

cartridges

(output

about

2.5mV):

When

the

FUNCTION

switch

(SI)

is

set

to

the

PHONO

1

position,

the

input

impedance

Zinl

(150kQ,

100pF)

of

equalizer

amplifier

is

con-

nected

in

parallel

with

R1

(75kQ)

across

the

PHONO

1

input

terminal.

They

serve

as

load

impedance

for

the

cartridge

used.

(R

=

50kQ,

C

=

100pF)

®

When

using

low

impedance

MC

cartridges

(output

about

125uV):

The

head

amplifier

is

connected

by

switching

S1.

At

the

same

time,

either

a

3Q

or

40Q

load

im-

pedance

(depending

on

cartridge

impedance)

is

also

connected

to

the

PHONO

1

input

terminal.

For

the

load

of

400

cartridge,

the

input

im-

pedance

Zin2

(100Q)

of

head

amplifier

is

employ-

ed,

and

for

the

load

of

322

cartridge

R2

(332)

is

connected

in

parallel

with

Zinl,

resulting

in

a

25Q

input

resistance.

PHONO

Tf

PHONO

7

ZINI

Ri

HEAD

AMP

ls

150kQ.

100pF

—FUNCTION—

PHONO

1

R2

&}

402—

7

HEAD

AMP

32

Fig,

1

PHONO

2

@

The

PHONO

2

input

is

basically

the

same

as

the

PHONO

1

input,

but

also

is

equipped

with

a

PHONO

2

PHONO

2

T

°

a

ae

|

rey.

OTL

a)

bf

6

2

r

|

~LOAD

R-

-LOAD

C—

10k

—100kQ.

100p—S00pF

(varied

in

10k9.

steps}

(varied

in

10OpF

steps)

Fig.

2

cartridge

load

selector.

It

is

adjustable

over

10k

to

100kQ

and

100pF

to

SO0pF

ranges

when

using

high

impedance

cartridge.

®

This

switch

(S801)

located

on

the

top

case

is

a

kind

of

rotary

switch.

Fig.

3

1-2-2.

Head

Amplifier

Generally,

the

very

low

level

signals

produced

by

an

MC

(moving

coil)

cartridge

are

amplified

by

step-

up

transformer.

On

the

other

hand,

in

the

TA-E88/TA-ES88B,

this

amplification

is

performed

by

a

built-in

head

ampli-

fier.

Although

the

use

of

active

amplification

ele-

ments

(rather

than

passive

transformers)

causes

some

deterioration

of

S/N

ratio,

these

problems

have

been

successfully

overcome

in

the

TA-E88/E88B

by

employing

parallel-connected

transistors

in

the

head

amplifier.

The

head

amplifier

includes

a

main

amplifier

stage

consisting

of

eight

transistors

(Q101

to

Q108)

con-

nected

in

parallel,

and

another

eight

transistors

(Q109

to

Q116)

differentially-connected

to

this

main

stage,

achieving

gain

of

27dB

with

usually-

low

noise.

buffer

amp

ey

output

input

4

_

—_

--3}-4

™

101-108

sits

i

Fig.

4

@

Parallel

Connection

When

a

transistor

is

used

for

amplification

pug-

poses,

the

current

flowing

between

the

collector

and

emitter

of

the

active

transistor

is

placed

under

control.

Signals

from

the

base

terminal

pass

through

the

internal

resistance

of

the

base

spread

resistance

rbb’.

(This

base

spread

resistance

is

one

of

the

critical

factors

which

have

to

be

considered

in

high

frequency

amplification).

The

detailed

diagram

is

shown

in

Fig.

5.

The

lower

the

rbb’

resistance,

the

less

the

noise

will

become.

This

may

be

achieved

by

connecting

transistors

in

parallel

—

n

transistors

connected

in

parallel

reduce

noise

by

1/v/n.

This

may

also

be

considered

as

parallel-connected

transistor

collectors

(noise

output

terminals),

resulting

in

the

averaging

out

of

noise

levels

and

phase

differences

of

the

noise

elements

in

each

transistor.

collector

Ie

base

rbb’

base

spread

resistance

re

emitter

effective

resistance

emitter

Fig.

5

head

amp

Fig.

6

1-2.3,.

Equalizer

Amplifier

The

phono

equalizer

amplifier

stage

consists

of

Q201

through

Q214.

In

order

to

design

the

TA-E88/E88B

as

a

direct-coupled

de

amplifier,

this

stage

includes

the

following

features:

@

AnFET

in

the

first

stage

i

|

TA-E88

/E88B

®@

The

Miller.

effect

by

caused

internal

capacitance

between

drain

and

gate

of

FET

in

the

first

stage

results

in

deterioration

of

high

end.

frequency

response

due

to

high

input

impedance.

To

prevent

this,

the

drain

of

FET

in

the

first

stage

is

connect-

ed

to

the

source

of

the

following

low

input

im-

pedance

transistor

(Q202).

The

impedance

of

the

equalizer

components

(R228.

to.

R230)

is

kept

low

to

further

improve

the

S/N

ratio.

The

equalizer

amplifier

output

stage

employed

to

drive

these

components

con-

sists

of

a

-2-stage

emitter-follower

push-pull

circuit.

A

dual

transistor,

featuring

two

pairs

of

elements

mounted

on

a

single

wafer,

is.

used

to

improve

the

thermal

and

pair

characteristics

for

different-

ial

operation

of

Q201,

Q202

and

Q205.

1-2-4.

Buffer

Amplifier

The

buffer

amplifier

(Q301

to

Q312)

up

to

the

equalizer

amplifier

has

a

gain

of

OdB.

That

is,

there

is

100%

negative

feedback

of

the

output

voltige

rom

the

output

terminal

to

the

input

negative

feedback

terminal.

This

amplifier

is

used

to

drive

BALANCE

control

and

ATTENUATOR.

Frequency

response

deterioration

will

occur

if

high-

value

resistors

are

used

in

the

step

attenuator.

The

TA-E88/E88B

employs

low

resistance

resistors

(3kQ).

This

also

resuits

in

decreased

thermal

nose.

A

buffer

amplifier

is

used

to

drive

the

low

resistarce

BALANCE

control

and

ATTENUATOR.

This

ampli-

fier

uses

a

differential-cascode

amplifier

in

the

first

stage.

Fig.

8

shows

the

location

of

the

FET.

variable

resistor

TA-E88/ES8B

FET

Fig.

8

1-2-5,

Output

Amplifier

The

output

amplifier

consists

of

Q401

to

Q414.

It

amplifies

signals

from

de

to

high

frequency

and

drives

OUTPUTs

1

and

2

of

TA-E88/E88B.

General-

ly,

an

output

amplifier

must

be

capable

of

delivering

high-level,

low-impedance

output

signals

to

match

a

wide

range

of

power

amplifiers.

For

this

reason,

the

TA-E88/E88B

is

designed

to

supply

an

output

signal

up

to

15Vrms

with

10092

output

impedance,

This

amplifier

stage

is

also

equipped

with

the

OUT-

PUT

LEVEL

switch

(S5)

to

permit

the

output

level

to

be

varied

in

10dB

steps.

The

four

selector

positions

are

0dB,

-10dB/

—20dB

and

OFF.

1-2-6.

Power

Supply

Both

left

and

right

channels

have

independent

power

supplies

which:

produce

the

+42V

and

—42V_

for

B

voltage,

plus

the

+14V-and-—14V

for

the

head

amplifier,

Power

supply

circuit

for

head

amplifier

consists

of

Ql

to

Q18.

(mounted

on

head

amp

power

supply

board

Bt

RY301

|

RY351

|Q902

T2

R906

|

D904

|

D903.

|

a904

(Nt)

fp

ig

ob

te

twee

er

secondary

ce

|

agar.

ate

1

alee

es

|

ot

Fig.

9

located

near

the

main

board).

The

reason

for

po-

sitioning

this

power

supply

as

close

as

possible

to

the

head

amplifier

is

to

prevent

the

introduction

of

extraneous

noise

on

the

B+

and

B—

bus.

1-2-7.

Relay

Drive

Amplifier

This

amplifier,

consisting

of

Q901

to

Q904

(mounted

on

the

rectifier

board),

drives

the

muting

relays

RY301

and

RY351.

These

muting

relays

operate

when

the

power

supply

switch

is

turned

on

and

off.

The

signal

path

is

completed

when

these

relays

are

turned

on

under

the

condition

described

below.

The

simplified

relay

drive

amplifier

circuit

is

shown

in

Fig.

9.

®

When

Power

Supply

is

Switched

On

1)

The

B+

and

B—

voltages

are

produced

as

soon

as

the

power

switch

is

turned

on.

2)

Since

the

base

of

Q902

is

connected

through

R906

to

an

uncharged

capacitor

C911,

the

base

voltage

is

ground

potential.

When

Q902

is

turned

on,

C911

starts

to

charge

up,

and

B+

and

B—

voltages

also

increase

gradual-

ly.

3)

After

the

B+

and

B—

voltages

have

become

stable,

and

C911

fully

charged

up,

Q902

and

Q903

turn

off,

resulting

in

Q904

turning

on

to

activate

the

relays.

The

output

signals

are

consequently

appear

at

the

output

terminals.

®

When

Power

Supply

is

Switched

Off

1)

As

soon

as

the

POWER

switch

is

turned

off,

Q901

(which

had

remained

off

due

to

D903)

and

Q902

turn

on,

and

then

Q903

also

turns

on.

Therefore,

Q904

(for

relay

drive)

turns

off.

2)

Although

both

B+

and

B—

voltages

commence

to

rapidly.

drop

to

zero

voltage,

Q901

remains

on

until

B+

voltage

reaches

about

1.2V

(Q901

VBE

Plus

voltage

drop

across

D904)

since

there

is

no

voltage

dividing

resistance

between

base

and

emitter.

of

Q901,

3)

When

B+

voltage

drops

below

1.2V,

Q904

may

be

turned.

on,

but

since

the

voltage

across

the

relay

is

less

than

the

minimum

voltage

required

to

activate.

the

relay,

the

relay

simply

remains

off

(or

muted).

4)

C912

prevents

the

misoperation

of

the

relays

due

to

the

pulse

noise

introduced

from

the

ac

line.

1-2-8.

REC

OUT

Buffer

Amplifier

The

REC

OUT

terminals

provide

fixed

level

output

signals

from

the

REC

OUT

buffer

amplifier

stage

(Q501

to

Q505}

between

the

equalizer

amplifier

and

buffer

amplifier.

1-2-9,

Overall

Amplifier

Although

the

TA-E88/E88B

consists

of

ten

de

ampli-

fier

stages,

all

of

these

stages

are

basically

the

same.

The

output

amplifier

is

described

here

as

an

example

of

one

of

these

stages,

|

TA-E88/E88B

|

Circuit

Description

@

When

observing

the

signal

levels,

the

0.2Vp-p

(about

—20dB)

input

signal

applied

to

the

gate

of

Veelp

characteristics

of

Q404

low

temperature

Fig.

11

shows

the

relevant

signal

levels

when

S5

is

Vee

|

VBE

set

to

OdB,

and

the

input

level

is

adjusted

to

obtain

——

;

.2Vp-p).

+

an

output

level

of

apoue

OdBrms

.

p-p)

The

;

Noh

iene

and

—

signs

refer

to

the

signal

polarity

at

that

point.

8B

re

Iptic

However,

the

(—)

sign

on

the

right

hand

gate

(NFB

input)

of

the

first

stage

Q401

indicates

that

this

was

+)

originally

a

negative

polarity.

Fig.

70

2

23

_

eee

ne

2Ve-

aeeve-p

\

/

i

/

\

/

food

\

f

|

/

yi

+

Sarees

t

ourput

“

pus,

;

r

7

/

Bt

era

Teal

aaa

7

dee

as

sf,

C408

[

R403

Tae

\caoa

Ree

ih

j

T

ay

0405

f

SSL

=

cone

P

C410

f

T

(Op

4

La

output

fe

EF

|

___

mot,

|

Fig.

17

fevel

G407

collector

{

d8)

@

f

95

6.5,

eee

i

iis

Q411,

413

Q407 gate

|

emitter

—~20

{

oe

—~20dB

i

NFB

77dB

(0.21

Vp-p)

'

{

40

+

i

‘

Q407

voltage

gain:

77d8

60

i

-

I

0405

i

voltage

gain:

hd

77dB

80

1

——

jx

OQ408R

Q401

gain

1308

~

—84d8

collector

O401L

drain

CS

sales

Ge

Rna

he

Maes

ure

Ota

Se

Ge

de

Gs

att

as

~700

—97dB

Q407

gate

(with

no

NFB)

Fig.

42

ls

N

Lgain

when

applying

|

NFB:

20dB

J

open-loop

gain:

$7dB

Note:

The

—6.5dB

{evel

(dotted

line

in

figure)

in

addition

to

the

OdB

level

(theoretical

value)

at

the

0407

collector,

is

an

example

of

the

error

incurred

due

to

the

load

effect

when

measuring:

with

an

ac

voltmeter

of

1MQ

input

resistance.

The

7dB

shown

as

the

gain

(between

base

and

collector)

for

Q405

is

the

voltage

gain.

This

is

important

because

since

Q405

employs

the

emitter

of

O407

(low

input.

resistance)

as

collector

load

of

G405..

This

gain

should

really

be

measured

as

current

ratio.

Q401

is

not

measured

at

the

drain

of

Q401

(12).

However,

2.2Vp-p

(about

OdB)

signal

appears

at

the

collector

of

Q407,

and

is

extracted

from

the

emitter

follower.

The

level

diagram

is

shown

in

Fig.

12.

An

NFB

of

77dB

is

applied

to

the

amplifier

which

has

97dB

open-loop

gain.

Since

the

gain

of

an

NFB

amplifier

is

reduced

only

by.

the

amount

of

NFB

applied

to

that

stage,

the

level

at

the

drain

of

the

Q401

becomes

—84dB.

This

is

the

reason

why

the

signal

level

is

too

low

to..be

measured

at

the

intermediate

points

of

amplifier.

D401,

Q403,

Q404

and

D402

form

a

thermally-

compensated

constant

voltage

circuit,

which

operates

as

follows

(the

voltages.

referred

to

here

are

relative

to

the

B=

voltage):

D402

(EQBO1-05)

is

a

SV

zener

diode

which

maintains

the

emitter

of

Q404

at

+5V.

level.

To

obtain

a

flat

base

voltage

(VBR).

from

the

collector

of

Q404,

the

base

and

collector

are

connected.

as

shown

in

Fig.

10.

The

characteristics

referring

to

this

connection

are

also

shown

in

Fig.

10.

When

the

value

of

Vpp

reaches

the

“shoulder”

of

the

curve,

it

suddenly

becomes

constant,

and

subsequently

varies

only

with

changes

of

tempe-

rature.

Any

temperature-related.

variations

‘in

VBE

of

Q404

are

fed

to

Q402,

but

since

Q402

and

Q404

are

identical

transistors,

these

variations

are

automatically

compensated

for

by

the

other

transistor.

Hence,

Q402

and

Q404

serve

to

comen-

sate

for

any

voltage

variations

caused

by

changes

of

temperature.

Q403

is

a

2SK42

N-channel

depression

type

FET.

As

shown

in

Fig.

13,

EG

=

ES

when

gate

and

source.

are

connected,

resulting

in

the

flow

of

a

constant

current

of

less

than

SmA.

In

other

words,

Q403

serves

as

the

load

resistance

for

Q402.

!p

characteristics

of

depression

type

FET

(EG

=

ES)

Fig.

13

Q402

has

an

emitter

resistor

with

sufficiently

high

resistance

to

obtain.

constant.

base

voltage,

which

means

that

the

emitter

current

(collector

current)

always

remains

constant.

A

bipolar

transistor

type

constant.

current

circuit

such

as

this

can

provide

highly-constant

current

at

low.

supply

voltages.

Q401

is

a

cascode

connection

with

the

polarity

from

the

lower

gate

to

the

upper

drain

as

shown

in

Fig.

11,

@

Q405,

Q406

and

Q407

form

the

second

cascode-

connection

differential

amplifier.

Q408,

Q409

and

Q410

(current-mirror

circuit)

serve

as

the

load

resistance

for

Q406

and

Q407.

The

output

from

this

differential

amplifier

appears

single-ended

at

the

collector

of

Q407,

while

the

signal

on

the

collector

of

Q406

is

passed

from

Q408;

0410

to

Q409,

Q407

and

Q409

drive

Q411

and

Q412.

Furthermore,

although

Q409

also

operates

as

a

constant

current

circuit,

and

the

Q407

collector

current

is

passed

through

R418

and

R419

to

Q411

and

Q412,

signals

of

almost

equal

amplitude

are

passed

to

these

two

transistors

(Q411

and

Q412).

In

addition,

the

thermal

compensation

for

O410R

and

Q409

is

achieved

by

Q410L

and

0408.

@

Q411,

Q412,

Q413

and

0414

form

a

cross

coupled

current

driver

circuit,

comprising

pairs

of

NPN,

PNP

emitter-followers.

CAUTION

The

transistors

have

a

resistor

to

their

collector

or

emitter

circuits.

These

transistors

will

be

not

damaged

if

any

of

transistor

terminals

are

short-circuited,

The

exception

is

Q403

which

supplies,

constant

current

to

D401,

Q404

and

D402.

Ifthe

drain

and

source

of

Q403

are

short-circuited,

D401, Q403,

Q404

and

D402

will

be

completely

destroyed.

1-3.

Parts

Information

1-3-1.

Small

Resistors

The

TA-E88/E88B

uses

many

small

resistors,

similar

to

the

type

shown

in

Fig:

14.

These

resistor:

are

“%W

metal-oxide

with

an

accuracy

of

1%.

Notethat

this

accuracy

rating

has

been

omitted

in

the

sclema-

tic

diagrams.

(The

“4W.

and

%W

carbon

resstor

accuracy

ratings

are

indicated),

shows

multiplier

18

00

Gu.

represents

15k

€2

metal-oxide

resistor.

Fig.

14

1-3-2.

Square

Tantalum

Capacitors

The

capacitors:

employed.in

the.

TA-E88/E88B

(as

shown

in.Fig:.

15)

are

the

same.

square.

tantauna

capacitors

used

in

pulse

circuit

power

supplies,

stc:

These

capacitors-are

especially

used

in

the

B+

andp—

bus

where

their

greater

by-pass

effect

is

neeed..

square

tantalum

capacitor

ce

Fig,

18.

1-3-3.

Mounting

of

Components

When

mounting

the

components

on

the

circuit

board,

take

care

that

they

do

not

touch

the

shafts

of

switches;

variable

resistors;

etc.

Be

particularly

careful

to

prevent

any

contact

between

the

com-

pound

FET

covered

by

metal

case,

and

the

ATTENU-

ATOR

shaft,

and

the

diode

leads

and

BALANCE

control

shaft.

Fig.

16

1-3-4,

Cam

Equipped

Switch

Indication

The

selector

switches

employed

in.

TA-E88/E88B

are

each

equipped

with

a'cam,

and

a

number

(3.

or

4)

of

slide.

switch

elements

which

move.

in.

an’

irregular

fashion

when

the

cam

rotates.

As.an

example

of

this

arrangement,

S1L

(FUNCTION

PHONO

INPUT)

is

shown

in

Fig.

17.

There

are

a

total

of

ten

switches

employed

in

the

TA-E88/E88B,°

making

it.

impossible

to

‘determine

which.

points

are

making

contact

at.

different

select

positions.

For

this

reason,

both

the

schematic.

dia-

gram

and

the

mounting

diagram

include

special

charts

of

the

contact

patterns

for

each

switch

position.

Bato

wie

|

TA-E88/E88B

|

J

Note

that

these

charts

indicate

the

position

of

the

blue

switch

link

heads

as

viewed

from

the

com-

ponent

side,

thereby

simplifying

checking

operations

as

well.

FUNCTION

oo

PHONO

14

400.

———

HEAD

AMP

<

:

aq

LOW.

FILTER

ISHz.42dB/OCT

_

PHONO2—\

movement

of

switch

contacts

viewed

from

component

side

Fig.

18

SIL-1

\

S{L-2

|

selector

links

when

SIL-3

setting

SIL

to.

step

3

(top

view}

SIL-4

:

SIL

(FUNCTION

PHONO

Switch}

viewed

from

component

side

Fig.

19

1-3-5.

Order

of

Parts

in

Switch

Assemblies

cam

A

typical

switch

assembly,

including

the

switch,

the

joint,

front

panel

and

selector

knob,

is

shown

in

Fig.

20.

Whenever

such

switch

assemblies

are

taken

apart,

the

pesition

of

parts

must

be

noted,

either

by

mark-

ing

each

part,

or

by

some

other

method.

link

1-3-6.

Switch

Angle

Alignment

(See

Fig.

21.)

|

This

switch

is

turned

on

or

off

through

the

switch

|

links

and

switch

cam.

A

feature

of

the

switch

is

switch

elements

the

absence

of

click

stops

which.

determine

the

actual

switching

position.

Therefore,

it is

necessary

to

correctly

align

the

selector

knob

precisely

with

its

corresponding

switch

position.

Fig.

217

a

:

joint

knob

switch

i

ai

circuit

board

front

panel

detent

selector

shaft

Fig.

20

—10—

SECTION

2

DISASSEMBLY

TA-E88/E88B

Note:

Follow

the

disassembly

procedure

in

the

numerical

order

given.

CASE

REMOVAL

@

B4x8

-

9

@

case

screws

ee

y

:

@

>

case

screws

=

@

BV3

x

6

(eleven)

BOTTOM

PLATE

REMOVAL

Q

bottom

plate

fe

ATTENUATOR

KNOB

REMOVAL

it)

Loosen

the

set

screw

with

an

L-shaped

hexagonal

wrench

(1.5mm)

@

ATTENUATOR

knob

moval.

Note:

Other

knobs

can

be

removed

after

the

panel

re

Pe

fy

TA-E88/E88B

PANEL

REMOVAL

@

Loosen

two

set

screws

with

an

L-shaped

hexagonal

wrench

(1.5mm)

[

KNOB

REMOVAL

|

1

Loosen

the

set

screws

with

an

L-shaped

hexagonal

wrench

(1.5mm)

from

the

bottom

side

of

the

panel.

Pull

the

knobs

out.

nh

/

pe

roo

we

i

$

n

\

Loosen

four

set

screws

with

@

PS3

x6

@

PS3

x

6

and

an

L-shaped

hexagonal

wrench

and

RK4

xe

(1.5mm).

RK4

x8

5]

Pull

the

pane!

out.

{Knobs

are

attached

to

the

panel.)

CIRCUIT

BOARD

CHECKING

Circuit

boards

can

be

repaired

without

removal.

With

electrolytic

capacitors

near

the

conductor

side

of

head

amp

power

supply

boards

discannected,

the

head

amp

power

supply

boards

can

be

checked.

rectifier

board

main

board

head

amp

power

supply

board

ae

bt

eos

Sony TA-E88 User manual

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