Onkyo TA-2550 User manual

TA-2550

SERIAL

NO.

3300

ONKYO

SERVICE

MANUAL

STEREO

CASSETTE

TAPE

DECK

Black

and

silver

model

SAFETY-RELATED

COMPONENT

WARNING!!

COMPONENTS

IDENTIFIED

BY

MARK

“4

ON

THE

SCHEMATIC

DIAGRAM

AND

IN

THE

PARTS

LIST

ARE

CRITICAL

FOR

RISK

OF

FIRE

AND

ELECTRIC

SHOCK.

REPLACE

THESE

COM-

PONENTS

WITH

ONKYO

PARTS

WHOSE

PARTS

NUMBERS

APPEAR

AS

SHOWN

IN

THIS

MANUAL.

MAKE

LEAKAGE-CURRENT

OR

RESISTANCE

MEASUREMENTS

TO

DETERMINE

THAT

EXPOSED

PARTS

ARE

ACCEPTABLY

IN-—

SULATED

FROM

THE

SUPPLY

CIRCUIT

BEFORE

RETURNING

THE

APPLIANCE

TO

THE

CUSTOMER.

ONKYO.

AUDIO

COMPONENTS

SPECIFICATIONS

Track

Format:

4-tracks,

2-channels

Erasing

System:

AC

erase

Tape

Speed:

4.8

cm/sec.

(1-7/8

i.p.s.)

Wow

and

Flutter:

0.045%

(WRMS)

Frequency

Response:

20—17,000Hz

(Normal)

(30—16,000Hz

+

3dB)

20—18,000Hz

(High)

(30—17,000Hz

+

3dB)

20—19,000Hz

(Metal)

(830—18,000Hz

+

3dB)

S/N

Ratio:

60dB

(metal

tape,

Dolby

NR

off)

Anoise

reduction

of

10dB

above

5kHz

and

5dB

at

1kHz

is

possible

with

Dolby

B

NR.

A

noise

reduction

of

20dB

at

5kHz

is

possible

with

Dolby

C

NR.

Input

Jacks:

Line

IN:

2

Input

sensitivity:

6(OmV

Input

impedance:

50kohms

Outputs:

Line

OUT:

2

Standard

output

level:

500mV

(OdB)

Optimum

load

impedance:

over

50

kohms

Headphone

jack:

1

Optimum

load

impedance:

8

to

200

ohms

Motors:

DC

servo

motor:

1

DC

motor:

2

Heads:

REC/PB:

Special

Hard

Permalloy

x

1;

Erase

head:

Ferrite

x

1

Power

Supply

Rating:

AC

220V,

50Hz

Power

Consumption:

19

watts

Dimensions:

435(W)

x

132(H)

x

366(D)mm

(17-1/8"

x

5-3/16"

x

14-3/8")

Weight:

§.8

kg.

(12.8

Ibs.)

Specifications

and

external

appearance

are

subject

to

change

without

notice

because

of

product

improvements.

TA-2550

REC/PB

level

—>

SERVICE

PROCEDURES

1.

Replacement

of

power

supply

cord

There

are

two

power

supply

cord

outlets

on

the

strainrelief.

Insert

them

in

prescribed

direction

to

ensure

safety.

AS-UC-

3

(UD<120V>

model)

should

be

inserted

lengthwise

and

other

types

of

cords

should

be

inserted

horizontally.

Power

Supply

Cord

Power

Supply

Cord

Horizontal

length

wise

4

direction

2.

Insulating

resistance

measurement

Connect

the

insulating-resistance

tester

between

the

plug

of

power

supply

cord

and

chassis.

Specifications;

SOOV

more

than

1OMQ

HX

PRO

CIRCUIT

OPERATION

EXPLANATION

1.

Regarding

recording

frequency

characteristic

and

bias

Ordinarily,

if

the

recording

bias

current

is

increased,

REC/PB

frequency

response

level

in

the

high

frequency

region

(about

10KHz

and

above)

drops,

and

if

the

bias

is

decreased,

the

response

rises.

ai

Bias

decrease

4

Frequency

>

ene

<—_———_

Bias

increase

REC/PB

level

2.

Regarding

the

basic

operation

of

HX

PRO

(Refer

to

Fig.

1)

The

HX

PRO

uses

the

~%

PC1297CA

IC.

The

operation

is

in

accordance

with

the

following.

1)

At

(a),

the

recording

bias

is

added

onto

the

audio

signal,

and

the

recording

signal

is

detected.

This

is

the

same

as

the

recording

head

recording

the

signal

on

the

tape.

The

signal

of

1)

preserves

the

frequency

response

with

the

integrated

circuit

of

(b).

R450

+

R448

(2.1)

2m

xX

C426

x

R450

x

R448

*”

By

means

of

the

frequency

of

Fig.

1,

the

frequency

which

is

effective

from

the

beginning

is

determined.

In

the

ordinary

situation,

this

is

half

the

audio

band

(10KHz),

(1OKHz

~

7.5KHz).

At

(c),

in

order

to

use

the

affected

waveform

after-ward,

absolute

detection

is

carried

out.

Frequency

=

Rise

a

Frequency

—>

4)

At

(d),

the

waveform

peak

value

is

detected.

The

output

becomes

the

peak

DC

voltage.

5)

At

(e),

the

standard

voltage

and

the

voltage

of

(4)

are

compared.

6)

With

the

output

of

(e),

the

frequency

generation

level

is

controlled

(voltage

controlled

amplifier).

That

is,

the

bias

size

is

varied.

7)

Summing

up

1)

~

6):

At

(a),

the

time

constant

(frequency)

that

is

detected

in

the

recording

signal

is

preserved,

and

above

a

certain

frequency

and

above

a

certain

level,

the

VCA

controls

the

bias

current

by

causeing

its

reduction.

When

this

is

done,

in

the

maner

shown

in

the

explanation

of

Item

I

above,

the

frequency

high

region

is

raised.

With

this

control,

the

audio

signal

is

instantaneously

dealt

with.

.

Regarding

the

operating

conditions

of

the

HX

PRO

With

equation

(2.

1)

noted

above,

the

effect

begins

at

the

frequency

thus

determined.

Above

a

certain

level

the

effect

begins.

(Substantially

0

dB:

In

the

vicinity

of

500mV

line

out)

The

audio

signal

component

level

is

dependent

upon

the

waveform

after

point

(c).

2)

HX

PRO

BLOCK

DIAGRAM

a

ee

a

=

Vee

:

|

8}

VOLTAGE

pPC1297CA

|

REGULATION

i

|

AND

THERMAL

IAS

1,

|

PROTECTION

Oy

gg7

OSCILLA

|

10P

I

=

|

H

|

I

|

©

*)

i

\

!

VCA

er

ee

VCA

|

K

I

{

PEAK

ABSOLUTE

PEAK

|

@

DETECTOR

|

-

®

|

am

|

©

|

(ea

Seer,

eter

bs

Se

a

ea

Sala

ze

4

=

1C436

R448

0.047

C430

ae

100K

R447

0.1

:

il

100K

ae:

ee

BIAS

CURRENT

R468

10K

osc

10K

=

BIAS

~

yt

el

i

INTEGRATING

ADJUST

|

AOJUST

BIA

CIRCUIT

C424

T0426

CUR

9.01

0.01

LEFT

RIGHT

CHANNEL

RECORD

HEAD

AUDIO

exe

HEAD

SIGNAL

®

cut

ofr

Pe

R450+R448

20

xC426

xR450

x

R448

Fig.

|

-|

rif

NO

a

72)

Oo

_

SRAM

NRA

Reon

BLOCK

DIAGRAM

PB

AMP

BIAS

P.B

Q160

TRAP

LEVEL

L101

R107

PB

_<

¥

HEAD

DOLBY

ty

DINLAMP

SELECTOR

$301.$302

DIN

OUT

RISS

R157

DINE

N

MUT

0

a223

9

869

LINE

aisi

MPX

in

BUFFER

FILTER

|

oy

Ss

L201

Po

utne

be

QO

OUT

5

LINE

MUT

Q221

TAPE

SELECTOR

BIAS

OSC

Q427.0428

2401

a:

«a

¢

SE

DOL

BY.

DECODER

Q101

=

TAPE

Q211

Q213

SOURCE

DOLBY

ENCODER

Q203

ACCU

R466

Q303

MICRO

COMPUTER

2

METER.

AMP

TP.1

R501

Qso1

Q722

BUFFER

a2i7_

|%235

EAD.PHONE|

AMP

Q301

—]

6

—

|

OUT

rec

amp

=

|

BLAS

R413

0403

L407

_-otp3

HX

PRO

—we-

2467

Q415

VV

Bae

ee}

AE

OSS¢e-VL

RI

REMOTE

CONTROL

OPERATION

MICRO

COMPUTER

Q701

MICRO

COMPUTER

@s501

REAL

TIME

COUNTER

Q722

—_+-

0901~

0904

3

—+<4—

0905,0906

MICRO

COMPUTER

(HD614042SH57)

HD614042SH57

PLAY

LED

t¢

H

rp

REPEAT

3

H

FULL

H

BLOCK

[5

|

H

F.L,

DISPLAY)

TAPE

[6]

H

SOURCE

H

|

rene

TuneD

WeL8]

H :

A

H

ACCU

BUSY

7

H

BIAS

CONT

24

DIN

MUTE

13

REC

MUTE

%4

LINE

MUTE

15

TEST

SOURCE

TAPE

ACCU

7

BALANCE

CHECK

POWER

OFF

18

SEARCH

SIG

L

CASS

IN

O

REC.

INH.

C

ROTATION

SENSOR

|

22|

(TAKE

UP

SIDE)

,

Bi

MECHA

POSITION

oo

SWITCH

a

REEL

BA

ASSIST

MOTOR

O|

|

REEL

MOTOR

@

|

[ace

ew

S)

oO

[2

NTI

SEL

iS]

|

Ure

tesa

tb

steps

GS

Saat

ee

BIS

‘S

ne

ae

CAPSTA

es

{

30]

MOTOR

:

CAP

CONTROL

4

Fa;

@:

3

Ter

321

Veg

Stk

MECHANICAL

POSITION

CODE

QO701

#23

#24

#25

Mode

L

H

L

PLAY

—

PAUSE

STOP

L

oH

H

L

H

H H

L

FF,

REW

cS)

ono

so

Gl

o~o

60]

o~o

so]

oo

8]

So

Yo

i

Sea

Yo

TEST

\

@)

O

o

-

TIMER TIMER

53)

T~B

REC

4MHz

LT

50}

+5V

3]

28]

a7]

45)

3

Ce

Ec

42

kale

ra

ss)

Sf

S

IE

NRSC

IN

i

lee

if)

TA-2550

PAUSE

LED

AMCS

FWD

AMCS

BACK

ACCU

START

ACCU

RESET

REPEAT

MONITOR

P

STO

FL

REW

SYSTEM

RESET

PLAY.

REC

PAUSE

AUTO

SPACE.

DA

OUT

TO

REAL

TIME

|

COUNTER

+5V

|

.

ONRSC

I/O

REMOTE

CONTROL

DECODER

4L-

REMOTE

CONTROL

TA-2550

IC

BLOCK

DIAGRAM

NCHC-3205

(P.B.

AMP)

@

oe

ae

QUT

rowo

NJM2068MD

ONKYO

NHIC-3205

222078

Lech

PEAK

HOLD

CR

Lech

AC

IN

Rch

PEAK

HOLD

CR

Rch

AC

IN

CX20187

(DOLBY

N.R)

BIC

LINE

IN

Vee

PB

IN

SSK

VF

IN

HPF

H

TCH2

TCH!

WT

H

TCL2

Tcl

Wow

HPF

L

ANTS

arene

nH

5

Ne

ee

IREF

LINE

IN

Vee

PB

IN

MPX

OUT

REC

IN

GNO

LINE

OUT

SSK

VF

IN

131]

HPF

H

|

30]

TCH2

[29]

TCHI

[28]

wT

H

TCL2

26]

TCL

|

25]

WT

OL

P24)

HPF

L

123]

ANT

S

r

22]

REC OUT

:

4

:

;

:

q

=

i

HD614128SA41

(COUNTER)

Terminal

Name

and

Function

TA-2550

f-—#—

REMA/CONS

IN

REMA/

CONS

OUT

microcomputer

RES

€7

ADJUST

o~o-4

oom

/

Ex

Le—-ake

uP]

;

>

rotation

sensor

suey

|

No.

Name

Function

_

1~3

Grid

5~7

FL

tube

grid

(DIGIT)

drive

use

output

4

Vdisp

Input

(FL

tube

use)

for

minus

bias

voltage

to

Nos.

1

~

3,

5,6,9

~

16,

39

~

42

|

5

CONS

FL

tube

display

use

output

(time

lapse)

7

6

REMA

FL

tube

display

use

output

(time

remaining)

9~15

a~g

FL

tube

segment

drive

use

output

16

Colon

|

FL

tube

“:”

drive

use

output

[418

T,/T2

|

Microcomputer

T,

/T2

function

selection

input

(With-T,

,

system

I/O

receiving)

Deck

mechanism

status

input

(8

bit

serial

data)

from

mechanism

control

micro-

Sg

abies

computer

|

20

CLOCK

Clock

input

for

reading

above

DATA

(DATA

taken

on

pulse

wave

dropping)

21

Vee

Microcomputer

power

source

(+5V)

22

SUPPLY

Cassette

mechanism

tape

feed

side

turning

pulse

input

|

23

TAKE

UP

Cassette

mechanism

tape

windup

side

turning

(pulse

input

)

14

DOM/EX

Domestic/export

setting

use

selector

input

(Tape

size

type

selector

use)

Domestic:

With

power

ON

C46—>

C54

-—>

C60

>

C80

>

C90

>

C120

254

25

ADJUST

ane

buffer

compensating

value

input

(normally

open,

26

RESET

Microcomputer

system

reset

27

TEST

Microcomputer

internal

test

use

port,

normally

connected

to

Vcc

|

28,29

|

OSC1,

OSC2

Microcomputer

clock

oscillator

terminal

30

GND

Microcomputer

power

source

(GND)

31

SIZE

Tape

size

selector

input

|

32

RESET

Lapsed

time

reset

input

(When

displays,

digits

are

0

:O

O)

33

CONS/REMA

/

Lapsed

time

« +

remaining

time

selector

input

(toggle

display)

34

BOUT

System

bus

output

|

35

BIN

System

bus

input

I

|

36

REMA/CONS

OUT

__|

Remaining

time

display/lapsed

time

display

status

output

(when

T3)

37

REMA/CONS

IN

Remaining

time

display/Japsed

time

display

status

input

(when

T.)

39~42

|

Grid

1

~4

FL

tube

grid

(DIGIT)

drive

use

output

|

_7-

TA-2550

ADJUSTMENT

PROCEDURES

PRECAUTIONS

1.

Before

adjustment,

clean

the

following

parts

with

an

alchol

moinstend

swab,

*

record/playback

head

*

pinch

roller

*

erase

head

*

capstan

2.

Do

not

use

magnetized

screwdriver

for

adjustments.

3.

Demagnetize

record/playback

head

with

a

head

de-

magnetizer.

TEST

EQUIPMENT/TOOLS

REQUIRED:

Audio

oscillator

Digital

frequency

counter

Oscilloscope

Attenuator

AC

voltmeter

Non-magnetic

screw

driver

Test

tapes

VTT-658

10

KHz,

—15dB

MTT-1E1

3

kHz,

—10dB

MTT-150

Dolby

level

calibration

400Hz,

tone

200nWb/m

Item

Connyenion

pt

Line

input

Test

tape

er

Put

adipsia

Adjust

Remarks

instrument

indicator

point

Frequency

Tape

counter

to

Frequency

|

Semi-fixed

3,005

to

Speed

LINE

output

MN

i

counter

on

the

motor

3,010Hz

terminal

ee

sent

ieas

Maximum

and

Head

scope

to

VTT-658

PB

AC

Head

azimuth

same

phase

Fie

azimuth

voltmeter

|

screw

at

channels

LINE

output

3

LandR

terminal

AC

voltmeter

Playback

|

to

terminals

°

AC

R-107

(Ch.L)

level

TP-1

and

a

ce

voltmeter

|

R-108(Ch.R)

|

245™V

TP-2

1

le

et

;

Level

R-501

(Ch.L)

Meter

MTT-150

PB

|

eee

R-502(Ch.R)

0dB

NADIS-3339

T

F

AC

voltmeter

a

to

terminals

METALTAPE|REC

[M0

|

bi

ae

Minimum

|

ap

TP-1

and

TP-2

|

sits

AC

voltmeter

IR-467

to

terminals

AC

L-409

(Ch.L)

;

R-468

eke

TP-3

and

METS

aA

EE

BES

voltmeter

|

L-410(Ch.R)

Meautar

counter

TP-4

clock

wise

:

AC

voltmeter

IkHz,

—20dB

7

a

_

t@LINE

output

|

and

NEW

XL-I190

|

REC/PB

on

:

ue

en

panes

wiput

-

urren

serail

12kHz,

—20dB

voltmeter

-468

(Ch.R)

at

maximu

a

REC

AC

Attenutor

or

350mV

Reged

voltmeter

|

AF

OSC

output

Input

VR

:

level

Rig?

Thee

ores

KeCRE

Tae

R-413(Ch.L)

—_|

Same

level

car

ae

voltmeter

|

R-414(Ch.R)

at

REC/PB

Blank

tape

NORMAL

.........

UD-1

C-90

PLAY

torque.............

30

—

60g/cm

HIGH

ce

leas

XL-I

C-90

FF.REW

torque

...........

70

—

140g/cm

METAL

..........

MX

C-90

Back

tension

.............

2

—

Sg/cm

Fe

Aer

ere,

Cee

Ca

ae

Calan

ich

acaapeDb

ches

Bebe

se

daca

ee

TA-2550

NCAF

—

3334

id

122

ae

REC

LEVEL

Bias

TRAP

R413

(

R416

(R}

aks

pe

(0)

(2)

413

(L)

®

[e]

®

i

R467

(L)

R468

(R)

Pe

po

BIAS

ADJ

LEVEL

TP3

TPS

L609

L410

HX

PRO

_

RS02

(R)

R501

{L)

METER

NCDIS-3339

OSCILLOSCOPE

oe

AF

OSC

Attenuator

LINE

IN

LINE

VTVM

;

OUT

0°

(IN

PHASE)

4s°

90°

180

fig-2

:

}

i

Confirming

phase

relationship

i

fig-1

i

a

|

TA-2550

CHASSIS-EXPLODED

VIEW

Pe

LOSE

EET

AE

eT

TENT

ITY

CEE

Be

SRG

NS

CRA

Ee

2

meet

Onkyo TA-2550 User manual

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