Nakamichi Bx-125 User manual

Nakamichi

Service

Manual

Nakamichi

BX-125

BX-125E

2

Head

Cassette

Deck

CONTENTS

2.

3.

1.

General

34.65

3.4)

helt

eo

attire

Eanes

Stra

ty,

ala

Ae

a

earths

Ras

Seats

keel

d

eae

Rd

A

oe

coe

aBeoatedel

ty

hae

Ae

1

Test:

Tapes

and:Gauges

«3.05006

3.5

ie

ev

cnewinaa

Pd

Soro

ve a.

ON

goods

SES

RP

de

oboe

BOR

la

ek

Gi

ee

2

Mechanical

Adjustments:

2265-0516

666.002

Vinod

Baia

GS

Soslle

WR

ats

Bed

eee

wie

Peewee

De

betta

ey

ihe

2

38. 21.

Tape

Guide

Height

Check

for

Record/Playback

Head

and

Erase

Head

................-02..

2

8.

2.

Head

Base

Stroke

Check

......

0.0...

0c

cece

eee

ee

een

eee

e

ene

ce

ee

2

3.

Record/Playback

Azimuth

Alignment

and

Height

Check

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

0.00

eececcces

2

3.

4,

Pressure

Adjustment

of

Pressure

Roller...

2...

ee

eee

e

eee

3

3. 5.

Tape

Travelling

Check

oo.

5.0

3.56e

eee

ee 8b

adie

Beck

kG

ae

olga

bags

S08

OM

Row

ahaa

ncaa

3

3.

«6.

Eject

Damper

Adjustment

.........

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c

cece

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eben

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b

ee

neee

3

3.

7.

Reel

Motor

Speed

Adjustment

in

Play

Mode

.........

0.0...

00.

cece

eee

ence

e

een

ee

3

3. 8.

Tape.

Speed

Adjustments

se.

5)

5

ee

eees

koe

Svea

cee

he

eae

Bek

Bk

ea

bo

ly

OR

hg

3

3.

9.

TUBPiCAbION

65)

oso.

3.

S552

eo

ANE

ek

Ea

eylee

wee

aticel

Pode

A

et

es

ae

a,

ened

mnaese

pata

no

Le

3

Parts

Location

for

Electrical

Adjustment

.........0.0

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ene

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nenas

4

Electrical

Adjustments...:3.

6

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cvidieie

Gis

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5

be

0

bbe

ae

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bw

N

Oe

bb

ab

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waa Nba

bs

5

5.

1.

Adjustment

Instructions

2...

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00

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ee

eee

e

epee

ne

eens

5

5.

2.

Playback

Frequency

Response

Adjustment

..........

0.000

ee

ece

ce

cee

eee

neeyees

7

Mechanism

Ass’y

and

Parts

List...

1.1...

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ne

en

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een

e

eee

een

eneuns

8

6.

1.

SY

MEN

SSI9

25

32

vetig

sn

red

ce

yarn

tas

hence

yt

a

teu

peer

Me

osc

eae

eye

ae

reese

ay

Bee

a

eat

a

BE

cect

8

6.

2.

Synthesis

Mechanism

Ass’y

(A01)

........0.0

0.00.

cece

eee

ee

eee

een

eee

eenns

9

6.

3.

Mechanism,

Ass’y-(BOL)

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5S

be

Gh

edivnc

ohaccw

ee

vba

vane

Seals

ese

av

hh

tbody

elation

g

11

6.

4.

Rear.

Panel.

Ass’y

(B02)

©

ss...

cosy

dace

sb

eee

ooo

wie

ae

Dae

G

aE

eagle

bia

13

Mounting

Diagrams

and

Parts

List

..

0.0.0...

occ

ee

eee

ee ee

een

eee

nen

ene

eennnas

14

PALL

Power

Switch

P.C.B.

Ass’y

2.0...

ccc

ec

eee

tne

ec

eee

e

eee

eseerteeeuas

14

Te

2.

GED:

PCB:

Assy

se

ise

laced

tn.

Gey

ee

8

a

aaa

ts

need

eesti

ee

ea

late

gto

tee

ae

be

TA

7.

8.

Timer

Switch

P.C.B.

Ass’y

......

GiRaEES.

oh

toni

Semin

es

3.8,

codons

Ie

settaco

a

encumid

inno

wind

14

7.

4,

Shut-off

P.C.B.

Ass’y..........

Poe

Gable

elk

ahd,

See

im,

do

Gis

oe

datos

dh,

Blige

ce

de

ge

onde

Mitbne

IS

Be

EM

ee

ge

eae

de

14

7.

6.

Dolby

NR

Switch

P.C.B.

Ass’y

2...

eee

nee

bbe

nae

15

7.

6.

Volume

PC.

Bs

Assy

0

scsi

bea

a

Seay

ahiacs

whee

Ras

ig

oe

aud

atone

Pons

d

ate

ah

Be

oe

SO

15

7.

Control

Switch

P.C.B.

Ass’y

2...

ee

eee

ee

eee

eben

een

nenns

15

7.

8.

Tape

Switch

P.C:B.

Ags?

V

oe

oh

eed

aaa

goed.

duels

we

Peg

Se

altaal

bce

bed

Gow

dow

Bablate

ohio

wees

16

7. 9.

Indicator

P:C.By

Ass?

Y

225-5:

Gee

wie

icky

bec

ROE

apd

Uae:

Degen

ati,

8

Bosh

bossa

eee

aoe

wha

ate

Oe

eed

Behe

16

7.

10.

Main

PC

Bi

Ass’

si

Scares:

«

lead

deal

oda

Wo

wide

ee

bee

OO

ee

ash

Mate

Ape

ole

A

Natu

Mota

sod

Se

17

Schematic!

Diagtant

s,s.

5

soo

2

sires

an

ere

Bh

woke

vee

bob

GH

Elander

ates

REE

Oo

Wee

eave

Wa

aioe

Cae

ia

ache

tes

bo

19

8.

1.

I€

Block:

Diagrams...

032i

a)a

aise

48

a

peo

ere

a

Soa

B

Huy

does

wa

ga

old

bral

are

Wee aoa

19

8.

2.

Schematic

Diagram

.........

0.

cc

ce

ee

eee

teen

ee

cece

nent

en

naaea

20

Wiring

Diagranni

>:

,.0..6

sie

feet

ed

ite

hot

bin

Talay

Bobo

ds

SAR

Bw

aor

Re

wire

bof

ah

bln

au

Ele

eS

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acta

be

nw

Doe

Qoasans.

Godel

21

Block!

Diagrams’:

jc.

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fase.

cisco

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ale

wtay

ete.

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aha

ope

teies

«ay

Bar

EvaNGES,

gh

haouba

breceey

oeet

a

acieie

Rakdes

22

Timing

Chart

and

Eq.

Amp,

Frequency

Response

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

000

cee

cece

eet

eee

e

een

eeennas

24

Specifications:

2

vi

see

esse

cess

puetiotn

vo

oe

olin

Bole

Rite

toolny

ca

ko

ee

erie

Aa

©

alata

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oh

DEEN

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tas

Re

ee

eve

26

GENERAL

1.1.

Voltage

Selector

Voltage

selector

is

installed

on

the

rear

panel

for

Other

version

of

the

Nakamichi

BX-125.

This

voltage

selector can

select

either

120

V

or

220-240

V

at

customer’s

disposal.

1.2.

Packing

Materials

and

Owner’s

Manual

o

“

Part

No,

Description

Q

OFO3855A

Carton

Box

BX-125

(Silver)

OF03857A

Carton

Box

BX-125

(Black)

OFO3856A

Carton

Box

BX-125E

(Silver)

OFO3858A

Carton

Box

BX-125E

(Black)

OF03674C

=

Packing

0D04517A

Owner’s

Manual

(English)

0D04518A

Owner’s

Manual

(English/German/French)

0D04522A

Owner's

Manual

(Japanese)

HR

Dee

1.3.

Serial

Number

The

BX-125/BX-125E

has

two

versions,

Silver

and

Black.

In

the

service

manual,

serial

numbers

of

these

versions

are

identified

as

follows:

Silver

version:

A322xxxxx

Black

version:

A323xxxxx

However,

the

actual

serial

number

on

the

serial

number

plate

of

the

BX-125/BX-125E

is

indicated

as

A322.3xxxxx.

The

serial

number

begins

with

A322.301001.

ees

Sanath

2.

TEST

TAPES

AND

GAUGES

(1)

400

Hz

Level

Tape

(DA09005B)

(2)

1

kHz

Track

Alignment

Tape

(DA09007B)

(3)

15

kHz

Azimuth

Tape

(DA09004B)

(4)

3

kHz

Speed

and

Wow/Flutter

Tape

(DA09006C)

(5)

10

kHz

PB

Frequency

Response

Tape

(DA09003B)

(6)

15

kHz

PB

Frequency

Response

Tape

(DA09002B)

(7)

20

kHz

PB

Frequency

Response

Tape

(DA09001B)

(8)

Tape

Travelling

Cassette

(DA09027B)

(9)

Reference

EXII

Tape

(DAO9066B)

(10)

Reference

SX

Tape

(DA09025B)

(11)

Reference

SX-E

Tape

(DA09086A)

(12)

Reference

ZX

Tape

(DA09037B)

(13)

Head

Alignment

Gauge

(DA09092A)

3.

MECHANICAL

ADJUSTMENTS

3.1.

Tape

Guide

Height

Check

for

Record/Playback

Head

and

Erase

Head

With

use

of

a

Head

Alignment

Gauge,

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

Head

Alignment

Gauge.

Refer

to

Fig.

3.1.

(1)

Record/Playback

Head

Tape

Guide

Height

(a)

Load

the

base

of

the

Head

Alignment

Gauge

carefully

and

set

the

cassette

deck

in

Play

mode.

(b)

Place

the

small

block

of

the

Head

Alignment

Gauge

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

Head

Alignment

Gauge

carefully

and

set

the

cassette

deck

in

Play

mode.

(b)

Place

the

small

block

of

the

Head

Alignment

Gauge

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,

3.2,

Head

Base

Stroke

Check

Refer

to

Fig.

3.2.

{1)

Load

the

base

of

the

Head

Alignment

Gauge

carefully,

then

push

the

base

toward

the

Record/Playback

Head

to

eliminate

the

clearance

between

the

reference

and

the

base.

(2)

Set

the

cassette

deck

in

Play

mode.

(3)

Place

the

small

block

of

the

Head

Alignment

Gauge

on

the

base,

(4)

Contact

the

small

block

with

the

Record/Playback

Head

surface

and

the

Erase

Head

surface,

and

check

whether

the

end

of

the

small

block

is

located

within

the

specified

toler-

ance

as

shown

in

Fig.

3.2,

3.3.

Record/Playback

Azimuth

Alignment

and

Height

Check

Refer

to

Fig.

3.1.

(1)

Connect

a

VTVM

to

the

Output

Jacks,

(2)

Load

a

15

kHz

Azimuth

Tape

and

set

the

cassette

deck

in

Play

mode,

(3)

Turn

the

Azimuth

Alignment

Screw

until

the

outputs

of

both

channels

become

maximum.

(4)

Load

a

1

kHz

Track

Alignment

Tape

and

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,

Shim

3.4.

Pressure

Adjustment

of

Pressure

Roller

Refer

to

Fig.

3.3.

(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.

3.5.

Tape

Travelling

Check

Load

a

Tape

Travelling

Cassette

and

set

the

cassette

deck

in

Play

mode

to

check

the

followings:

(1)

After

more

than

2

seconds,

the

fluctuation

of

the

tape

travel-

ling

on

the

Record/Playback

Head

is

small.

(2)

Tape

is

in

contact

with

the

head

sufficiently.

(3)

Tape

waving

is

small

on

the

heads

and

pressure

roller,

3.6.

Eject

Damper

Adjustment

Refer

to

Fig.

3.4,

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

action

by

the

Damper

Adjustment

Screw.

CCW:

Damper

moves

fast.

CW:

Damper

moves

slowly.

3.7,

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.

3.8.

Tape

Speed

Adjustment

Refer

to

Fig.

3.5.

(1)

Connect

a

frequency

counter

to

the

Output

Jacks.

(2)

Load

a

3

kHz

Speed

and

Wow/Flutter

Tape

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.

3.9.

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

(8)

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,

Chiyoda-ku,

Tokyo,

Japan

(c)

Diamond

Oil

(EP-56)

Mitsubishi

Oil

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

Fig.

3.3

‘4

Increase

Damper

Adjustment

Screw

Fig.

3.4

Decrease

N

Increase

Fig.

3.5

4,

PARTS

LOCATION

FOR

ELECTRICAL

ADJUSTMENT

Main

P.C.B.

®

free

eo

Level

VR1I08

VR208

io)

(o)

MPX

iflter

vR6ol

Reel

Motor

Speed

VRIO4

VRI03

VRIO2

{Play}

EX

Rec.

Cal.

Sx zx

Playback

Level

VR204 VR203

VR202

@

oo

F102

TP103

(o)uss

Bias

Trap

(Record)

Peaking

TP203

TP102

pee

L203

TP202

T301

@

Bias Osc.

Frequency

A317

Bi

=

jas

ut

VR105

VRI06

VRIO7

U3

aee

VR205 VR206

VR207

Tape

Switch

P

C.B.

Fig.

4

5.

ELECTRICAL

ADJUSTMENTS

Note:

Electrical

adjustment

should

be

performed

after

mechanical

adjustment

is

completed.

5.1.

Adjustment

Instructions

OUTPUT

CONNECTION

Playback

Eq.

-

70

ys

Adjust

the

volume

incorporated

in

the

capstan

motor

to

obtain

3

kHz

+0.5%

on

the

frequency

counter.

Frequency

Counter

to

Output

Jacks

Tape

Speed

Adjustment

1.

Feed

in

400

Hz

and

adjust

the

Input

Level

controls

to

obtain

350

mv

-0.8

dB

on

the

VIVM.

2.

Adjust

VR108

(VR208)

so

that

the

0

dB

segment

of

the

level

meter

starts

illuminating.

3.

Adjust

the

Input

Level

controls

to

obtain

350

mV

on

the

VIVM,

then

decrease

the

generator

output

level

by

20

dB.

4.

Check

to

insure

that

the

segment

for

-20

dB

illuminates.

VIVM

to

TP101,TP201

on

Main

P.C.B.

Meter

Level|400

Hz

to

Record,

Pause/Main

Calibration]

Input

Jacks

Set

the

Output

Level

control

to

max,

Adjust

the

Input

Level

controls

to

obtain

500

mV

(0

dB)

on

the

VTVM.

2.

Set

the

MPX

Filter

switch

to

ON

and

adjust

L105

(L205)

to

obtain

minimum

reading

on

the

VIVM

(minimum

reading

will

be

less

than

-30

dB).

Record,

Pause|Main

MPX

-

OFF/ON

|P.C.B.

19

kHz

+100

Hz

to

Input

Jacks

MPX

Filter

Adjustment

Adjust

the

Record/Playback

Head

Azimuth

Alignment

Screw

to

obtain

maximum

readings

for

both

channels

on

the

VTIVM.

VIVM

to

Output

Jacks

Playback

Eq.

-

70

ps

Dolby

NR

-

OFF

MPX

-

OFF

Record/

Playback

Head

Azimuth

Alignment

Adjust

VR101

(VR201)

to

obtain

350

mV

on

the

VIVM.

VTIVM

to

Same

as

above|Main

TP101,TP201

on

Main

P.C.B.

400

Hz

Level

Tape

Playback

Level

Calibration

-

Load

a

400

Hz

level

tape

and

play

it

back,

Adjust

the

Output

Level

control

toa

certain

level.

2.

Load

10

kHz,

15

kHz and

20

kHz

PB

400

Hz

Same

as

above

|Main

Level

Tape|

Output

10

kHz

PB

|

Jacks

Frequency

Response

Playback

Frequency

Response

Adjustment

Tape

frequency

response

tapes

and

play

15

kHz

PB

them

back,

Adjust

the

record/play-

Frequency

back

head

azimuth

to

obtain

maximum

Response

readings

for

both

channels

on

the

Tape

VTIVM

with

each

tape.

20

kHz

PB

Short

R110

(R210)

or

R195

(R295)

on

Frequency

the

Main

P.C.B.

Ass'y

to

obtain

the

Response

following

levels

against

the

lewel

for

Tape

the

400

Hz

level

tape.

10

kHz:

-20

dB

-2

to

+2

dB

15

kHz:

-20

dB

-2

to

+3

dB

20

kHz:

-20

dB

-2

to

+4

dB

3.

Conduct

step

4

"Record/Playback

Head

Azimuth

Alignment".

STEP

ITEM

picasras

pena

REMARKS

pemecriiae

7

|Bias

Frequency

|Record,

Pause

Tape

-

Connect

an

additional

0.1

ohm

resistor

Oscillation

Counter

to

|Tape

-

ZX

in

series

to

the

Erase

Head

and

Frequency

CN2-2

on

Eq.

-

70

ps

-C.

connect

a

VIVM

across

it.

and

Erase

Tape

Switch]

Dolby

NR

-

2.

Adjust

T301

to

obtain

105

kHz

on

the

Current

P.C.B.

OFF

frequency

counter,

Adjustment

and

MPX

-

OFF

3.

Check

the

erase

current

by

the

VTVM.

310

mA

to

400

mA

(typically

approx.

VIVM

across

Erase

current

will

be

in

a

range

of

350

mA).

the

additional

0.1

ohm

If

erase

current

is

not

sufficient,

resistor increase

it

by

shorting

either

R318

or

R350.

4.

After

completion

of

the

erase

current

adjustment,

re-check

the

bias

oscillation

frequency,

5.

Remove

the

additional

0.1

ohm

resistor,

21

kHz

VIVM

to

Same

as

above|/Main

Short

the

bias

cut

points

indicated

in

Record

Amplifier

|(-20

dB)

|TP102,TP202

-C.B.

Fig.

4

with

a

clip

to

stop

bias

Equalizer

to

Input

on

Main

oscillation,

Adjustment

|

Jacks

P.C.B.

2.

Adjust

L102

(L202)

to

obtain

peak

reading

at

21

kHz

on

the

VIVM.

Remove

the

clip.

Adjust

L103

(L203)

to

obtain

maximum

reading

on

the

VTVM.

Bias

Trap

|None

VIVM

to

Same

as

above

Adjustment

|

(remove

TP103

,TP203

(Record

input

on

Main

Amp.)

signals)

|P.C.B.

Record

400

Hz

VIVM

and

Record

and

Adjustment

should

be

made

in

the

order

of

Level

(0

dB)

and}

Distortion

|Playback

ZX,

SX

and

EX.

Calibration|15

kHz

Meter

to

Tape

-

ZX/SX/|

(Level)

and

(-20

dB)

Output

EX

ZX:

1.

Set

the

Output

Level

control

to

max.

Recording

to

Input

|

Jacks

Eq.

-

70

ps

VR102

2.

Set

the

cassette

deck

in

Record/Pause

Bias

Jacks

(ZX/SX)

mode,

Current

120

ps

3.

Feed

in

400

Hz

and

adjust

the

Input

Adjustment

(EX)

Level

controls

to

obtain

500

mV

Dolby

NR

-

(O

dB)

on

the

VTVM.

OFF

4.

Load

a

reference

ZX

tape,

reference

MPX

-

OFF

SX/SX-E

tape

and

reference

EXII

tape.

5.

Feed

in

400

Hz

(0

dB)

and

record,

rewind

and

play

it

back.

Adjust

VR102

(VR202)

for

ZX

tape,

VR103

(VR203)

for

SX/SX-E

Tape

and

VR104

(VR204)

for

EXII

tape

so

that

the

played

back

output

levels

are

500

mV

(0

dB)

on

the

VTVM.

Feed

in

15

kHz

(-20

dB)

and

record,

rewind

and

play

it

back.

Adjust

VR105

(VR205)

for

ZX

tape,

VR106

(VR206)

for

SX/SX-E

tape

and

VR107

(VR207)

for

EXII

tape

so

that

the

played

back

output

levels

are

50

mV

(-20

dB)

on

the

VIVM.

7.

Repeat

above

5

and

6

two

or

three

times.

8.

Feed

in

400

Hz

(0

dB)

and

record,

rewind

and

play

it

back.

Check

to

insure

whether

the

total

harmonic

distortion

is

less

than

1.0%

for

ZX

and

EXII

tapes

and

1.2%

for

SX/SX-E

tape.

If

the

total

harmonic

dis-

tortion

exceeds

the

specified

value,

repeat

above

steps

till

satisfactory

results

are

obtained.

Switch

P.C.B.

(Bias)

a

ITEM

SIGNAL

OUTPUT

MODE

ADJUST~

SOURCE

CONNECTION

MENT

Overall

400

Hz

Record

and

Set

the

cassette

deck

in

Record/Pause

Frequency

|

(0

dB)

and|

Output

Playback

mode.

Response

20

Hz

to

Tape

-

ZX/SX/|

L102

Feed

in

400

Hz

and

set

the

Input

Level

Adjustment

|17

kHz

EX

controls

to

obtain

500

mV

(0

dB)

on

(-20

dB)

Eq.

-

70

ps

the

VIVM.

to

Input

(2X/SX)

Decrease

the

generator

output

control

Jacks

120

ps

by

20

dB.

(EX)

Feed

in

20

Hz

to

17

kHz

(-20

dB),

and

Dolby

NR

-

record,

rewind

and

play

them

back,

OFF

then

check

to

insure

whether

the

out-

MPX

SW

-

OFF

put

levels

are

within

-20

dB

+4

dB.

.

If

above

is

not

sufficient,

adjust

L102

(L202)

to

obtain

approx.

~20

dB

on

the

VIVM,

then

conduct

step

10

"Record

Level

Calibration

and

Recording

Bias

Current

Adjustment".

If

above

is

not

sufficient,

precise

re-adjustment

of

step

6

"Playback

Frequency

Response",

replacement

of

Record/Playback

Head

or

tape

travel-

ling

check

will

be

required.

5,2,

Playback

Frequency

Response

Adjustment

Figs.

5.1

and

5.2

show

the

playback

amp.

circuit

for

adjustment

The

peaking

portion

of

the

equalization

curve

compensates

the

and

the

playback

equalization

curve.

gap

loss

of

the

playback

head,

Peaking

level

is

varied

by

the

short

This

adjustment

will

be

required

if

playback

level

is

not

sufficient

circuit

of

R110

(R210)

or

R195

(R295).

when

a

20

kHz

PB

frequency

response

tape

is

played

back.

R

RIO

RI9S

(R210)

(R295)

680

1K

R/P

Head

VRIOt

[VR201)

Output

390P

HI

C108

(C208)

1000P

+H

C107

(C207)

120y8

Fig.

5.1

GAIN

(dB)

FREQUENCY

(Hz)

Fig.

5.2

6.

MECHANISM

ASS’Y

AND

PARTS

LIST

6.1.

Synthesis

01

HA04494B

0H04582B

0H04583B

0304628A

0H04306A

0H04240A

HA04571A

OJ04765A

OH04276A

0H04432B

0OHO3737A

0H04155B

0M04377B

0J04629A

0J04762A

OJ03564A

OE03054A

OE03033A

OEO0868A

OEOO865A

Description

Synthesis

Serial

No.:

432201001

-

(Silver)

Cassette

Case

Cover

Ass’y

Front

Panel

Ass’y

BX-125

Front

Panel

Ass’y

BX-125E

Top

Cover

Cushion

(Front)

Meter Cover

LED

Lens

Eject

Button

Ass’y

Spring

Counter

Escutcheon

Volume

Knob

Volume

Knob

Base

Top

Cover

Caution

Label

Top

Cover

Cushion

(Back)

Synthesis

Mechanism

Ass’y

Bottom

Cover

Leg

T-H

BT

3x8

©

Countersunk

BT

4x8

©

Pan

Washer-faced

(Nickel)

BT

3x8

©

Binding

BT

3x10

©

Binding

Fig.

6.1

PAT

PP

RPE

NN

BHP

PEN

ee

HA04495B

0H04584B

0H04585B

0J04628A

0HO04307A

0H04240A

HA04570A

OJO4765A

OH04275A

0H04342A

OHO3737A

0H04156B

0M04377B

0J04629A

0J04762A

0J03564A

OE03054A

0E03032A

OEOO868A

OEO00865A

Synthesis

Serial

No.:

A32301001

-

(Black)

Cassette

Case

Cover

Ass’y

Front

Panel

Ass’y

BX-125

Front

Panel

Ass’y

BX-125E

Top

Cover

Cushion

(Front)

Meter

Cover

LED

Lens

Eject

Button

Ass’y

Spring

Counter

Escutcheon

Volume

Knob

Volume

Knob

Base

Top

Cover

Caution

Label

Top

Cover

Cushion

(Back)

Synthesis

Mechanism

Ass’y

Bottom

Cover

Leg

T-H

BT

3x8

6

Countersunk

BT

4x8

©

Pan

Washer-faced

(Black

Chromate)

BT

3x8

©

Binding

BT

3x10

&

Binding

PWD

PPR

EEN

Re

Hee

6.2,

Synthesis

Mechanism

Ass’y

(AO1)

Nakamichi BX-125 User manual

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