Nakamichi BX-100 Manuale utente

Nakamichi

Service

Manual

Nakamichi

BX-100

BX-100E

2

Head

Cassette

Deck

CONTENTS

lL

4y

“General

45.5

54

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OR

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snd:

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2:

(Mechanical

Adjustments.

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wed

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egal

ab

wert

a,

ee

egtee

Ze. “Ly

Tape

Guide

Height

Check

for

Record/Playback

Head

and

Erase

Head

.............02

0.000%

2:

2.

Head‘

Base

Stroke

Check:

.0..-24-5-0

ashes

Nw

wee

RE

Se

ee

EA

PR

ee

2.

3.

Record/Playback

Azimuth

Alignment

and

Height

Check

.......

0...

cece

eee

eect

eeene

2. 4.

Pressure

Adjustment

of

Pressure

Roller...

0...

0.

cc

ee ee

ee

te

eee

2.

5.

Tape.

Travellirig:‘CReeh.

5.6

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ra

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Meee

Sas

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ie

anes

2.

6.

Eject

Damper.Adjustment:

<0.

0c

eesiscee

ie

se

oe

a

eee

oboe

Ue

Bie

HE

ert

Sa

he

hee

ee

2.

7:

Reel

Motor

Speed

Adjustment

in

Play

Mode

........

0...

cc

cece

eee

ee

te

eee

ee

ene

nae

2. 8.

Tape’

Speed

Adjustment:

éiiiic

5

alla

ics

BSG)

alg

ee

We

we

EE

Rie

Bede

Wee

B

Soe

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ea

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ees

2...

9;

Gur

bricationy

5:55.60

eee

5

ace

Se

ate

wba

We

RPG

Us

womens

Se

ay,

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as

he

OU

ee

we

aw

a

eo

3.

Parts

Location

for

Electrical

Adjustment...

0...

2...

0.

cc

ee

eee

ee

te

ee

tees

4,

Electrical

Adjustments

and

Measurements

...........

52.

-

cece

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ee ee

eee

ee

eee

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een

eens

4.

1.

Adjustment

and

Measurement

Instructions

......

20...

0.

cece

eee

ee

eee

ee

eee

4,

2.

Playback

Frequency

Response

Adjustment

........

0.0:

ce

eee

ee

eee

ee

eee

eet

ene

4.

3.

Dolby

NR

Circuit

Check

0.0...

cc

ct ce re

ee

nw

ee

eee

ence

ene

n

eens

5...

Mechanism:Ass’y

and

Parts

List.

6.00

(5.6.

oe)

6

Sheie

6

5050s

ay

ES

0G

o

le

aca

fo

al6

Gay

Gre!

WIR

ole

BES

ww

Ra

De

Sere

awa

5.

1.

Synthesis:

ccct

sg

5:3

Sbiel

eee

ee

Beh

a

ee

Se

Nees

tee

Ree

eee

We

Ga

ce

tea

bn

Stee

A

Oya

Wel

a

ee

eae

5.

2.

Synthesis

Mechanism

Ass’y

(A001)

1.0...

ee

eee

5.

3.

Mechanism:

Ass’y:

(BOD)

os

occa

hire

tbe

has:

8

gee

es

Se

Rogues

BERS

OLA

aN

BERL

UD

Gack

Cater

a

onion

bose

5.

4.

Rear

Panel.

Ass’y.(BO2):

055.

coce

cc

ardy

gece

deece

la

Goes

wae,

oh

lah

as

©

pe

Gite

SENS

Wt

we

dte lhe

-8

eg

Rss

agenda

6.

Mounting

Diagrams

and

Parts

List

........

0...

cc

cece

eee

ee

eee

ee

eee

een

eee

ene

ee

6.

1.

Power

Switch

PC:

BiASs’y

<<

faci

8s.

Sak

eI

ar

%

wie

PS

SO

3

a

Sas.

3S

donate

Ws

Saal

ew

6.

2

Shut-off:

PC.

BsAss’y

sie

6.

sieve

cca

ae

ale

at's

belo

ode

de

eee~

alee SNR.

Nw

Ww

wise

Dh

apanss

toss

Wale

base

6.

3

Control:Switch:

PCBs

Assy:

sec

-n

esd

eso

aie

8

6.

0

eee

a

eae

a

cele

ens

Os

fe:

eh

0g

os

eae

ete

wee

ec

eh

else

6.

4

Timer

Switch:

P:C-B:

Asst

y=

cies

s0c

6S

Seay

aheng

oe

ai

S04

Soll:

aod

ese

SE

ey

to

we

giial

MER

en

Sl

nal

wa

SO

BS

OF

6.

5.

Volume:

P.C.B..

Ass?

yi

2.5.38.6

Bee

Seen

Eo

Acdo

wR

case

ae

ede

Seen

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evened

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alee

ed

6.

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NR:P.C:.B:

Ass’¥)

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goer

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eas

dhe

aces

te

eee

Bae

le

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Rake

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GIG

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6.

7

Tape

Switch:PiC

Bs

Asse’

y

4.coccce-goa

io,

ci/a2%

ge

18>

wi

Bhs

6D

lallav

eying)

tale

So

co

8i

Ste

rece

oa

aby

SGT

aa

Recetas

e

6.

8.

Indicator-P:C.B.

ASS’Y

cc

bees

ae

ew

EN

hw

Se

ee

He

es

Eta

i

Se

ee ae oP

alee

SMe

ee

6.

9.

Main:

PC.

BisAss’y

orteco

ed.

ca

ace

ods

ake,

Sub

tierenat

gscgeesr

ee

eS

ree

&

pw

eed:

Shore

el

Sia

ales

WS

aria

te

wa

oar

T

Sehematic

Dis

graimia..25.6..25-6

coed

Sins

Soe

Ne

Bo

GSO

BEE

wlan

a

ecg

gs

we

See

Ee

a

baa

ee

arcbuceris

dao

Gla

a

EEF

ee

Attention

to

Servicemen

2.666.606.5460

ee

bale

Be

ele

be

Oe

ae

eco

elas

2

ETE

be

ees

7.

2.

IG/Bloek:

Diagrarniss

2

sic

ies

din

eee

ee

oso

Wee

aaa:

wo

eee:

Bree

a

et

ee

Mebane.

hata

aye

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eel

7.

3.

Schematic-Diagrarns:.%.<.

o).ee-

cits

science

Ghee

gees

a8

5

OR

GST

WS

Rew

ieg

ecw

ERS.

WGN

Et

Teac

Sag

Wa

ES

ie

Bio

“Wiring

Diagrarny

oss

oisb

5

sor5

Sor

Sees

esi

oa

a

0a

AES

Wve

daye

MES

Bee

SN

Mea

Se

cea

oa

ca,

Seige

rena

ees

ay

oh

alanie

eee

eccaytee

es

9:

‘Block:

Diagrams

0:52.

86353

Gk

aia

wales

idl

cob

a4

eee

pe

Neate,

oo

aren

aa

Tee.

eee

wah

aries

Va

eye

aed

cateneral

ae:

SiN

a

aT

10.

Timing

Chart

and

Eq.

Amp.

Frequency

Response

.......

0.0...

cee

eee

ee

eee

te

eee

11,

Specifications

.............06--

Sig

et

GN

a

tas

Sie

Aa

dk

Rey Sao

WAG

Ma,

See

LaES

Se

ee

eRe

Taro

eee

lo

MACE:

Genres

tak

td

Sass

1.

GENERAL

1.1,

Voltage

Selector

Voltage

selector

is

installed

on

the

rear

panel

for

Other

version

of

the

Nakamichi

BX-100.

This

voltage

selector

can

select

either

120

V

or

220-240

V

at

customer’s

disposal.

1.2,

Packing

Materials

and

Owner’s

Manual

Part

No,

Description

Q

OFO3736A

Carton

Box

BX-100

(Silver)

OFO3750A

Carton

Box

BX-100E

(Silver)

OF03737A

Carton

Box

BX-100

(Black)

OF0O3751A

Carton

Box

BX-100E

(Black)

OF03674B

Packing

0D04311A

Owner’s

Manual

(BX-100.(U.S.A.,

Canada

&

Australia)

&

BX-100E

(UK))

0D04317A

Owner’s

Manual

(BX-100

(Others)

&

BX-100E

(220V

Class

2))

¢

<

BRN

HH

ee

1.3.

Serial

Number

The

BX-100

has

two

versions,

Silver

and

Black.

In

the

service

manual,

serial

numbers

of

these

versions

are

identified

as

follows:

Silver

version:

A318xxxxx

Black

version:

A319xxxxx

However,

the

actual

serial

number

on

the

serial

number

plate

of

the

BX-100

is

indicated

as

A318.9xxxxx.

The

serial

number

begins

with

A318.901001.

2.

MECHANICAL

ADJUSTMENTS

2.1.

Tape

Guide

Height

Check

for

Record/Playback

Head

and

Erase

Head

With

use

of

an

M-300

produced

by

Information

Terminals,

tape

guide

height

check

for

the

Record/Playback

and

Erase

Heads

shall

be

made,

wherein

a

small

block

shall

be

pushed

straight

down

to

the

base

while

in

use

of

the

M-300,

Refer

to

Fig.

2.1.

(1)

Record/Playback

Head

Tape

Guide

Height

(a)

Load

the

base

of

the

M-300

carefully,

then

set

the

cassette

deck

in

Play

mode.

(b)

Place

the

small

block

of

the

M-300

on

the

base.

(c)

Slide

the

small

block

against

the

tape

guide

of

the

Record/

Playback

Head,

and

check

to

insure

that

the

block

is

ac-

cepted

by

the

tape

guide.

(d)

If

not,

loosen

the

screw

and

insert

a

shim

(either

30

um

(0C80048A),

60

um

(0C80038A),

or

100

um

(0C80039A))

to

raise

the

Record/Playback

Head,

then

tighten

and

apply

a

quantity

of

lock

tight

paint

to

the

screw.

(2)

Erase

Head

Tape

Guide

Height

(a)

Load

the

base

of

the

M-300

carefully,

then

set

the

cassette

deck

in

Play

mode.

(b)

Place

the

small

block

of

the

M-300

on

the

base.

(c)

Slide

the

small

block

against

the

tape

guide

of

the

Erase

Head,

and

check

whether

the

block

is

accepted

by

the

tape

guide,

2.2,

Head

Base

Stroke

Check

Refer

to

Fig.

2.2.

(1)

Load

the

base

of

the

M-300

carefully,

then

push

the

base

toward

the

Record/Playback

Head

to

eliminate

the

clearance

between

the

reference

and

the

base.

(2)

Setthe

cassette

deck

in

Play

mode,

(3)

Place

the

small

block

of

the

M-300

on

the

base,

(4)

Contact

the

small

block

with

the

Record/Playback

Head

sur

face

and

the

Erase

Head

surface,

and

check

whether

the

end

of

the

small

block

is

located

within

the

specified

tolerance

as

shown

in

the

figure.

2.3.

Record/Playback

Azimuth-

Alignment

and

Height

Check

Refer

to

Fig.

2.1.

(1)

Connect

a

VTVM

to

the

Output

Jacks.

(2)

Load

a

15

kHz

Azimuth

Tape

(DA09004B),

then

set

the

cassette

deck

in

Play

mode.

(3)

Tum

the

Azimuth

Alignment

Screw

until

the

outputs

of

both

channels

become

maximum.

(4)

Load

a1

kHz

Track

Alignment

Tape

(DA09007B),

then

set

the

cassette

deck

in

Play

mode.

(5)

Check

to

insure

that

the

readings

of

both

channels

on

the

VTVM

are

below

—25

dB.

If

not,

replacement

of

the

Record/Playback

Head

will

be

required,

(6)

Apply

a

quantity

of

lock

tight

paint

to

the

Azimuth

Align-

ment

Screw,

2.4,

Pressure

Adjustment

of

Pressure

Roller

Refer

to

Fig.

2.3.

(1)

In

Play

mode,

measure

the

torque

of

the

Pressure

Roller

and

check

whether

the

torque

is

in

a

range

of

320

+50

g-cm.

(2)

If

torque

is

out

of

the

range,

correct

it

by

changing

the

instal-

lation

point

of

the

Pressure

Roller

Spring.

2.5.

Tape

Travelling

Check

Load

the

Tape

Travelling

Cassette

(DA09027B),

then

set

the

cassette

deck

in

Play

mode

and

check

the

following:

(1)

After

more

than

2

seconds,

the

fluctuation

of

the

tape

trav-

elling

on

the

Record/Playback

Head

is

small.

(2)

Tape

is

in

contact

with

the

head

sufficiently.

(3)

Tape

waving

is

smali

on

the

heads

and

pressure

roller.

2.6.

Eject

Damper

Adjustment

Refer

to

Fig.

2.4.

Load

a

cassette

tape,

and

with

opening

the

Cassette

Case

by

pressing

the

Eject

button

and

closing

it

by

hand,

adjust

the

speed

of

damper

movement

by

the

Adjustment

Screw.

cCW:

Damper

moves

fast.

CW:

Damper

moves

slowly.

Fig.

2.3

Decrease

Increase

Damper

Adjustment

Screw

2.7.

Reel

Motor

Speed

Adjustment

in

Play

Mode

(1)

To

warm-up

the

cassette

deck,

load

a

C-60

cassette

tape

and

set

the

cassette

deck

in

Play

mode,

(2)

After

more

than

four

minutes,

load

a

torque

meter

TW-211

(made

by

Sony)

and

set

the

cassette

deck

in

Play

mode.

(3)

Adjust

VR601

on

the

Main

P.C.B.

Ass’y

to

obtain

exactly

50

g-cm

on

the

torque

meter.

2.8.

Tape

Speed

Adjustment

Refer

to

Fig. 2.5.

(1)

Connect

a

frequency

counter

to

the

Output

Jacks.

(2)

Load

a

3

kHz

Speed

and

Wow/Flutter

Tape

(DA09006C)

and

play

it

back.

(3)

Adjust

the

Tape

Speed

Adjustment

Volume

incorporated

in

the

Capstan

Motor

to

obtain

3,000

Hz

on

the

frequency

counter,

CCW:

Motor

drives

slowly.

Cw:

Motor

drives

fast.

2.9.

Lubrication

The

tape

transport

is

of

a

lubrication-free

type

mechanism.

When

the

following

parts

are

replaced,

apply

the

specified

lubricant.

(1)

Molykote

(R)

Grease

(X5-6020)

Cam

Motor

Pulley

Thrust

portion

on

the

Capstan

Shaft

(2)

FLOIL

GB-TS-1

Washer

between

Reel

Hub

Ass’y

and

Back

Tension

Spring

(3)

Diamond

Oil

(EP56)

Reel

Hub

Shaft

(4)

Anderol

456

Capstan

Shaft

Note:

We

suggest

that

you

use

the

above

specified

lubricant

or

equivalent

type.

The

company

dealing

in

the

above

lubricant

is

as

follows:

(a)

Molykote

(R)

Grease

(X5-6020)

Dowcorning

Co.,

Ltd.,

1-15-1

Nishishinbashi,

Minato-

ku,

Tokyo,

Japan

(b)

FLOIL

GB-TS-1

Kanto

Chemicals

Co.,

Ltd.,

2-7

Kanda

Sakuma-cho,

Chiy

oda-ku,

Tokyo,

Japan

(c)

Diamond

Oil

(EP-56)

Mitsubishi

Of]

Co.,

Ltd.,

1-2-4

Toranomon,

Minato-ku,

Tokyo,

Japan

(d)

Anderol

456

Toyo

Kokusai

Oil

Co.,

Ltd,,

3-3-5

Hatchobori,

Chuo-

ku,

Tokyo,

Japan

Decrease

NH

Increase

Copstan

Motor

Fig.

2.5

3.

PARTS

LOCATION

FOR

ELECTRICAL

ADJUSTMENT

MPX

Filter

L104

L204

TP101

Playbock

Level

©

VREOI

Reel

Motor

Speed

(Play)

vR108

GL

VRIO1

vR201

ia

Level

vR208

@t

Bios

Trap

1P102@

Rec.Cal

(Record)

al

1P202©

Bit)

a

om

rrmro(@)

orezo3

Peaking

1304

@

Bios

Osc.

Frequency

©

|

Bias

Cut

©

VRIOS

VRIO6

yRI07

(2)

ios

To

VR205 VR206 VR207

Tape

Switch

P.C.B.

Fig.

3

4.

ELECTRICAL

ADJUSTMENTS

AND

MEASUREMENTS

Note:

Electrical

adjustment

should

be

performed

after

mechanical

adjustment

is

completed.

4.1.

Adjustment

and

Measurement

Instructions

Tape

Speed

Adjustment

Meter

Level

Calibration

MPX

Filter

Adjustment

Playback

Level

Calibration

Playback

Frequency

Response

Adjustment

Oscillation

Frequency

Adjustment

SIGNAL

OUTPUT

SOURCE

CONNECTION

3

kHz

Speed

and

Wow/Fliutter

Tape

(DA09006C)

400

Hz

to

Input

Jacks

400

Hz

and

19

kHz

+100

Hz

to

Input

Jacks

Azimuth

Tape

(DA09004B)

400

Hz

Level

Tape

(DA09005B)

400

Hz

Level

Tape

(DA09005B)

10

kHz

PB

Frequency

Response

Tape

(DA0900

3B)

15

kHz

PB

Frequency

Response

Tape

(DA09002B)

20

kHz

PB

Frequency

Response

Tape

(DA09001B)

(—20

dB)

to

Frequency

Counter

to

Output

Jacks

VTVM

to

TP101,

TP201

on

Main

P.C.B.

VTVM

to

Output

Jacks

VTVM

to

Output

Jacks

VTVM

to

TP101,

TP201

on

Main

P.C.B.

VTVM

to

Output

Jacks

Frequency

Counter

to

VTVM

across

the

additional

0.1

2

resistor

VTVM

to

TP102,

TP202

on

Main

P.C.B.

VTVM

to

TP103,

TP203

on

Main

P.C.B.

Playback

Eq.

SW

—

70

us

Record,

Pause

Record,

Pause

Playback

Eq.

SW—

70

us

Dolby

NR

SW

—

OFF

Same

as

above

Record,

Pause

Tape

SW

—

ZX

Eq.

SW

—

70

us

Dolby

NR

SW

—

OFF

Same

as

above

ADJUST-

MENT

Tape

Speed

Adjustment

Volume

Main

P.C.B.

VR108,VR208

Main

P.C.B.

L104,L204

Record/Playback

Head

Azimuth

Alignment

Screw

Main

P.C.B.

VR101,VR201

Main

P.C.B.

R110,R210

R195.R295

R318,R350

Main

P.C.B.

L102,L202

Main

P.C.B.

L103,L203

REMARKS

Adjust

the

volume

incorporated

in

the

capstan

motor

to

obtain

3

kHz

+0.5%

on

the

frequency

counter.

1.

Feed

in

400

Hz,

then

adjust

the

Input

Level

control

to

obtain

90

mV

—0.8

dB

on

the

VTVM.

.

Adjust

VR108

(VR208)

so

that

the

0

dB

segment

of

the

level

meter

starts

illuminat-

ing.

.

Adjust

the

Input

Level

control

to

obtain

90

mV

on

the

VTVM,

then

decrease

the

generator

output

level

by

20

dB.

.

Check

to

insure

that

the

segment

for

—-20

dB

illuminates,

.

Feed

in

400

Hz

and

adjust

the

Input

Level

control

to

obtain

0

dB

(500

mV)

on

the

VTVM.

.

Feed

in

19

kHz,

then

adjust

L104

(L204)

to

obtain

minimum

reading

on

the

VTVM

(minimum

reading

will

be

less

than --30

dB).

Adjust

the

Record/Playback

Head

Azimuth

Alignment

Screw

to

obtain

maximum

readings

of

both

channels

on

the

VTVM.

Adjust

VR101

(VR201)

to

obtain

90

mV

on

the

VTVM.

1.

Load

a

400

Hz

level

tape

and

play

it

back.

2.

Load

10

kHz,

15

kHz

and

20

kHz

PB

fre-

quency

response

tapes

and

adjust

the

record/

playback

head

azimuth

to

obtain

maximum

levels

on

the

VT

VM

with

each

tape.

.

Read

the

maximum

levels

with

each

tape

and

check

to

insure

that

the

levels

against

the

400

Hz

level

tape

are

within

the

follow-

ing

ranges.

If

not,

short

R110

(R210)

or

R195

(R295)

to

obtain

satisfactory

results,

10

kHz

(—20

dB)

—2

dB

to

+2

dB

15

kHz

(—20

dB)

2

dB

to

+3

dB

20

kHz

(—20

dB)

—2

dB

to

+4

dB

Refer

to

the

“Playback

Frequency

Response

Adjustment”

in

item

4.2

for

the

detailed

description.

.

Conduct

step

4

‘“‘Record/Playback

Head

Azimuth

Alignment”.

.

Adjust

T301

to

obtain

105

kHz

on

the

fre-

quency

counter,

.

Connect

an

additional

0.1

2

resistor

in

series

to

the

Erase

Head,

then

connect

a

VTVM

across

it.

.

Check

the

erase

current

by

the

VTVM.

Erase

current

will

be

in

a

range

of

145

mA

to

185

mA

(typically

approx.

165

mA).

If

erase

current

is

not

sufficient,

increase

it

by

shorting

R318

or

R350.

.

After

completion

of

the

erase

current

ad-

justment,

re-check

the

bias

oscillation

fre-

quency,

.

Remove

the

additional

0.1

2

resistor.

.

Short

both

Bias

Stop

test

pins

with

a

clip

to

stop

the

bias

oscillation.

.

Adjust

L102

(L202)

to

obtain

peak

read-

ing

at

21

kHz

on

the

VTVM.

.

Remove

the

clip

from

the

test

pins,

Adjust

L103

(L203)

to

obtain

maximum

read-

ing

on

the

VTVM.

SIGNAL

OUTPUT

ADJUST-

Ee

SOURCE

CONNECTION

|

move

|

MENT

REMARKS

Adjustment

should

be

made

in

the

order

of

ZX,

SX

and

EX,

.

Set

the

Dolby

NR

switch

to

OFF,

.

Connect

a

VTVM

to

output

Jacks,

.

Set

the

BX-100

in

Record/Pause

mode.

.

Feed

in

400

Hz,

then

adjust

the

Input

Level

control

to

obtain

500

mV

(0

dB)

on

the

VTVM.

.

Load

a

reference

ZX

tape

(DA09037A),

reference

SX

tape

(DA09025A)

and

refer-

ence

EXII

tape

(DAO9066A).

.

Adjust

Record

Cal.

VR102

(VR202)

for

ZX,

VR103

(VR203)

for

SX

and

VR104

(VR204)

for

EXII

to

center

positions,

.

Connect

the

VTVM

to

TP102

(TP202)

on

the

Main

P.C.B.

Ass’y.

Adjust

Bias

VR105

(VR205)

for

ZX,

VR106

(VR206)

for

SX

Main

P.C.B.

and

VR107

(VR207)

for

EXII

to

obtain

the

(Level)

following

bias

current

in

Record/Pause

ZX:

mode

(the

VTVM

is

connected

across

a

10-

VR102,VR202

ohm

resistor).

SX:

ZX:

approx.

1

mA

VTVM

to

Record

and

Playback

|

Vp103.VR203

SX:

approx,

0.5

mA

TP102,

TP202

EX:

EXII:

approx.

0.3

mA

on

Main

P.C.B.

z

VR104.VR204

.

Connect

the

VTVM

to

the

Output

Jacks,

and

‘

.

Feed

in

400

Hz

(—20

dB)

and

17

kHz

(—20

VTVM

and

(Bias)

aB),

then

record,

rewind

and

play

them

Distortion

Meter

|

Dolby

NR

SW

—OFF/|

7y,

back.

to

Output

Jacks

ON

|

VR105,VR205

Adjust

Bias

VR105

(VR205)

for

ZX,

SX:

VR106

(VR206)

for

SX

and

VR107

VR106,VR206

(VR207)

tor

EXII

to

obtain

the

same

play-

EX:

hae

devel

at

cael

ae

aB)

and

17

kHz

(—

B)

on

the

VT

%

VEIOLYR20e

.

Feed

in

400

Hz

(0

dB),

then

record,

rewind

and

play

it

back.

Adjust

Record

Cal.

VR102

(VR202)

for

ZX,

VR103

(VR203)

for

SX

and

VR104

(VR204)

for

EXII

to

obtain

0

dB

on

the

VTVM.

.

Repeat

above

9

and

10

two

or

three

times

to

obtain

optimum

performance.

.

Set

the

Dolby

NR

switch

to

ON.

.

Feed

in

400

Hz

(—20

dB),

10

kHz

(—20

dB)

and

17

kHz

(—20

dB),

then

record,

rewind

and

play

them

back.

Check

to

insure

that

the

playback

levels

are

within

+2

dB

against

the

levels

in

Dolby

NR

OFF.

Check

to

insure

whether

the

total

harmonic

distortion

is

less

than

1.0%

for

ZX

and

EXII

tapes

and

1.2%

for

SX

tape.

.

If

above

is

not

sufficient,

repeat

9

to

14

till

satisfactory

results

are

obtained.

.

Set

the

BX-100

in

Record/Pause

mode.

.

Feed

in

400

Hz,

then

set

the

Input

Level

control

to

obtain

0

dB

(500

mV)

on

the

VTVM.

.

Decrease

the

generator

output

control

by

20

dB.

i

—

an

400

Hz

(0

dB)

Record

and

Playback

’

Read

awed

sad

uae

ita

Coad

Anes

Overall

and

20

Hz

to

Tape

SW

—

ZX/SX/EX

;

check

to

insure

whether

the

output

levels

Frequency

17

kHz

VTVM

to

Eq.

SW

—

70

us

Main

P.C.B.

are

within

—20

dB

+4

dB.

Response

(20

dB)

to

Output

Jacks

(ZX/SX)

L102,L202

.

If

above

is

not

sufficient,

adjust

L102

Adjustment

|

Tout

Jacks

120

us

(EX)

(L202)

to

obtain

approx.

—20

dB

on

the

Dolby

NR

SW

—

OFF

VTVM,

then

conduct

step

10

“Record

Level

Calibration

and

Recording

Bias

Current

Adjustment”’,

.

If

above

is

not

sufficient,

precise

re-adjust-

ment

of

step

6

‘‘Playback

Frequency

Re-

sponse’,

replacement

of

Record/Playback

Head

or

check

on

item

2.5

“Tape

Travelling

Check”?

will

be

required.

.

ered

the

tape

with bulk

eraser.

"

.

Adjust

the

Input

Level

control

to

obtain

1kHz

Band

Pass

|

Record

and

Day

back

0

dB

on

the

VTVM,

and

record

the

signals

Filter

and

VTVM

Eq.

SW

—

70

us

on

the

reference

ZX

tape

(DAO9037A).

to

Output

Jacks

Doiby

NR

SW

—

OFF

.

Turn

the

cassette

tape

the

other

way

round

and

play

it

back.

.

Measure

the

difference

between

2

and

3.

.

Erase

the

tape

with

bulk

eraser.

Channel

.

Adjust

the

Input

Level

control

to

obtain

Separation

|1kHz

to

O

dB

on

the

VTVM,

and

set

the

Balance

Measure-

Input

Jacks

control

to

the

extreme

left

(right).

ment

:

.

Record,

rewind

and

play

it

back,

then

mea-

sure

the

R

ch

(L

ch)

level.

1

kHz

to

Input Jacks

Same

as

above

Same

as

above

SIGNAL

OUTPUT

ADJUST-

Erase

the

tape

with

bulk

eraser,

2

Adjust

the

Input

Level

control

to

obtain

O

dB

on

the

VTVM,

and

record

the

signals

on

the

reference

ZX

tape

(DA09037A).

3.

Rewind

the

tape,

set

the

Input

Level

control

to

minimum,

and

then

record

again.

4.

Rewind

the

tape,

play

it

back,

and

then

measure

the

difference

between

2

and

3.

Set

the

Dolby

NR

switch

to

ON,

Feed

in

400

Hz,

then

record,

rewind

and

play

it

back.

Adjust

the

Input

Level

control

to

obtain

3%

Record

and

Playback

Tape

SW

—

ZX

Eq.

SW

—

70

us

Dolby

NR

SW

—

OFF

100

Hz

Band

Pass

Filter

and

VTVM

to

Output

Jacks

100

Hz

to

Input

Jacks

IHF-A

Curve,

Record

and

Playback

sop

eo

NP

Filter,

VTVM

total

harmonic

distortion

in

Playback

mode.

tapout

gaa

and

Distortion

aed

lire

Set

the

Input

Level

contro!

to

minimum

Meter

to

:

then

record

again.

Output

Jacks

Dolby

NR

SW

—

ON

.

After

rewound,

play

back

and

check

the

output

level

difference

between

3

and

4.

Note:

The

filter

of

IHF-A

curve

shall

be

used

in

the

measurements,

Adjust

the

Input

Level

control

to

obtain

0

dB

on

the

VTVM.

2.

Record,

rewind

and

play

it

back.

3.

Read

the

distortion

meter

and

check

to

Record

and

Playback

Tape

SW

—

ZX/SX/EX

Eq.

SW

—

70

us

VTVM

and

400

Hz

to

Distortion

Meter

; ;

Fi

h

Input

Jacks

(ZX/SX)

insure

that

the

distortion

is

as

follows:

to

Output

Jacks

120

us

(EX)

EXI].....

1.0%

or

less

Dolby

NR

SW

—

OFF

SX

gow

hee

1.2%

or

less

yn

1.0%

or

less

3

kHz

Speed

and

Wow/

Flutter

Tape

(DA09006C)

Wow/Flutter

Meter

to

Output

Jacks

Playback

Eq,

SW

—

70

us

Play

back

and

read

the

wow/flutter

meter.

4.2.

Playback

Frequency

Response

Adjustment

R

RIO

R195

Figs,

4.1

and

4.2

show

the

playback

amp,

circuit

for

adjustment

R/P

ya

(nzash

and

the

playback

equalization

curve.

Head

This

adjustment

will

be

required

if

playback

level]

is

not

sufficient

during

playing

back

a

20

kHz

PB

frequency

response

tape.

The

peaking portion

of

the

equalization

curve

compensates

the

gap

loss

of

the

playback

head.

Peaking

level

is

varied

by

the

short

120ps

circuit

of

R110

(R210)

or

R195

(R295).

Lol

{L20)

VRION

(VR201)

Output

390P

Hi

C107

(C207)

C108

{C208}

1000P

GAIN

(dB)

100

400

1K

2K

10K

20K

FREQUENCY

(Hz)

Fig.

4.2

4.3.

Dolby

NR

Circuit

Check

Dolby

NR

circuit

incorporates

a

Dolby

NR

IC

(ZA7300PC)

which

has no

adjustment

point.

Perform

the

following

checks

and

make

sure

that

the

IC

operates

accurately

ie.,

frequency

response

through

IC

is

accurate.

(1)

(2)

(3)

Signal

Source:

1.4

kHz

to

Input

Jacks

Output

Connection:

VTVM

to

TP101

(TP201)

and

negative

side

of

C141

(C241)

on

the

Main

P.C.B.

Mode:

Record/Pause

Connect

a

VTVM

to

TP101

(TP201)

on

the

Main

P.C.B.

Ass’'y,

Feed

in

1.4

kHz

and

adjust

the

Input

level

control

so

that

the

VTVM

may

read

90

mV

(0

GB)

at

each

test

point.

Level

meter

will

indicate

0

dB.

Remove

the

VTVM

from

TP101

(TP201)

and

reconnect

it

to

the

negative

side

of

C141

(C241).

Decrease

the

input

level

(0

dB)

by

20

dB

or

30

dB.

Check

to

insure

that

the

level

at

negative

side

of

C141

(C241)

corresponds

to

the

following

with

the

Dolby

NR

switch

ON

and

OFF.

Input

Level

at

negative

side

of

C141

(C241)

at

TP101

(TP201)

|

Dolby

NR

OFF

|

Dolby

NR

B-Type

9mV

OdB

+3.2

dB

+1.5

dB

2.85

mV

0

dB

+8.2

dB

+1.5

dB

MECHANISM

ASS’Y

AND

PARTS

LIST

5.

5.1.

Synthesis

Fig.

5.1

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