Nakamichi BX-300 Bedienungsanleitung

Nakamichi

Service

Manual

Nakamichi

BX-300

BX-S3O00E

Discrete

Head

Cassette

Deck

CONTENTS

2.

3.

10.

11.

12.

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Test

Tapes

and

Gauges:

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Adjustment’

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3

3.

#1.

Record

Head

and

Playback

Head

Tilt

Adjustment

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0...

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3

3.

2

Head:

Base:Stroke:

Cheek:

$0537.66

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&

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bat

See

ew

ata

BS

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Bata?

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3

3.

3

Erase

Head

Stroke

Adjustment

and

Tape

Guide

Height

Check

...................200c0ee

3

3.

4

Erase

Head

Height

and

Tilt

Adjustment

........

0.00...

cece

eee

ee

eee

4

3.

5

Playback

Head

and

Record

Head

Height

Adjustment

and

Azimuth

Alignment

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

4

3.

6

Pressure

Adjustment

of

Take-up

Pressure

Roller...

0.0...

0.0.0.0

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3.

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Check.

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5

3.

8

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Damper

Adjustment

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3.

9

Reel

Motor

Speed

Adjustment

in

Play

Mode

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5

3.

10.

Tape

Speed

Adjustment

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Parts

Location

for

Electrical

Adjustment...

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Electrical

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5.

1.

Adjustment

Instructions

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7

5.

2.

Playback

Frequency

Response

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0...

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9

Mechanism

Ass’y

and

Parts

List...

2...

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10

6.

1.

Synthesis:

<seSsrah

piece

Samad

wine

eee

seed

ae:

die

na

arc

hat

BP

tec

ibxk

bite,

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10

6.

2.

Front:Panel;

Ass’y

(AOL).

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oo 68

06 oe

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wie

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bee

Sa)

WOE

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11

6.

3.

Synthesis

Mechanism

Ass’y

(A02)

..

0...

cc

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11

6.

4.

Front:

Chassis

Ass’y:(BO1)..6

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bn

Poe

Secs

d

Ww

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nk,

Ea

a

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De

12

6.

5.

Cover:

Plate

Ass’y

(BOQ):

(ois

ic

hccono

oes

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Gea

aeS ele

Pe

Se

aust

Sw)

bs,

ig

Bw

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bod

fend

wives

Boece

13

6.

Mechanism:

Ass’¥

(BOS).

5.5

o..scsyrsicarce

ed ee

4

co

oe

a

Ra

Ow

RH

ISIWY

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14

6.

7.

Rear'PanelAss’y

(B04)

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15

Mounting

Diagrams

and

Parts

List

..

2...

1.

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ees

15

7

1.

Power

Switch

P.C.B:

Ass’

63

6

ésec5:

oe

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be

a

as

BEN

ale.

rd,

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iw

Wels

LTR

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erate

15

7

2.

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RUS

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15

7.

3.

Fuse:

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c5

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op

co

S

conte

at,

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5b,

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ates

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16

7.

4.

Volume'P.C.B:

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a

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16

7.

65.

Input:Amp:

P:C{B.

Ass?y

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oe

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wn

ek

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S,

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Stennis

17

7.

6.

Meter

Amp.-P:C:BiAss’Y

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52h

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bl

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17

7.

7%,

Dolby

NR:

Switch:

P:C.B:

Assy.

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oi6:

6

see

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ewok

ae

ohn

Bik

0

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ee

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a

aes

er

EN

ah

bok

17

7.

8.

Control

Switch

P.C-B:

Assy

3265

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3,

ce,

6s

ea

sw

Oe,

ben

Wine.

BAS

wR

RAG

SUR

re

BS

RG

18

7.

9.

Counter

PCB.

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diss.

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5)

200 ose

enh

ose

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ren

0

ese

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wren

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6

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back

wd

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18

7.

10.

Tape

Switch:P:C.

Bi

Assy

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aire

a

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19

Schematic

Diagrams

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23

8.

1.

IC:

Block:

Diagrams

<2

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sie

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23

8.

2.

Schematic:

Diagrams:

>

535.5

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ch

aco:

Siew

ae

Ceara

word

Blea

dane

Wa

Ss

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we

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24

Timing

Chart

and

Eq.

Amp.

Frequency

Response

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26

9.

1.

Timing:

Chart:

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2,

Eq.

Amp.

Frequency

Response

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26

Wiring:

Diagram

isis

i

ison

5

8

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28

11.

2.

Mechanism

Control

Section

.......

0...

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29

Specifications

ics:

Ses

eh

hy,

58

as

Fe

te.

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BS

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SE

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ad

“ah dca

acaners

30

1.

GENERAL

1.1,

Voltage

Selector

Voltage

selector

is

installed

on

the

rear

panel

for

Other

version

of

the

Nakamichi

BX-300.

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

OF03812A

Carton

Box

BX-300

(U.S.A.,

Canada,

Australia

&

Others)

OFO03821A

Carton

Box

BX-300

(Japan)

OF03813A

Carton

Box

BX-300E

OF03674C

Packing

DAO3800A

Extension

Cord

0D04450A

Owner’s

Manual

BX-300

(U.S.A.,

Canada

&

Australia)

0D04451A

Owner’s

Manual

BX-300

(Japan)

DA03801A

Owner’s

Manual

BX-300E

&

BX-300

(Others)

2.

TEST

TAPES

AND

GAUGES

(1)

400

Hz

Level

Tape

(DA09005B)

(2)

1kHz

Track

Alignment

B

Tape

(DA09087B)

(3)

10

kHz

PB

Frequency

Response

Tape

(DA09003B)

(4)

15

kHz

PB

Frequency

Response

Tape

(DA09002B)

(5)

20

kHz

PB

Frequency

Response

Tape

(DA09001B)

(6)

15

kHz

Azimuth

Tape

(DA09004B)

(7)

3kHz

Speed

and

Wow/Flutter

Tape

(DA09006C)

(8)

Tape

Travelling

Cassette

(DA09071A)

(9)

Reference

EXII

Tape

(DA09066B)

(10)

Reference

SX

Tape

(DA09025B)

(11)

Reference

SX-E

Tape

(DA09086A)

(12)

Reference

ZX

Tape

(DA09037B)

(18)

EH

Tilt

Check

Gauge

S

(DA09088A)

(14)

Stroke

Check

Gauge

S

(DA09090A)

(15)

Tape

Guide

Height

Check

Gauge

S

(DA09091A)

(16)

Tilt

Check

Gauge

S

(DA09039B)

(>)

BRE

RN

ERE]

“¢

3.

MECHANICAL

ADJUSTMENT

3.1,

Record

Head

and

Playback

Head

Tilt

Adjustment

Remove

the

Cover

Plate

Ass’y

by

loosening

two

screws,

Refer

to

Fig.

3.1.

(1)

Remove

the

pad

lifter

from

the

playback

head.

(2)

Load

a

Tilt

Check

Gauge

S

in

the

cassette

deck,

(3)

Clip

the

grounding

terminal

of

the

Tilt

Check

Gauge

with

one

end

of

the

cord

with

clip,

and

the

chassis

of

the

cassette

deck

with

the

other

end.

(4)

Remove

both

of

the

Height

Gears,

(5)

Set

the

cassette

deck

in

Play

mode.

Check

to

insure

whether

the

Beacons

Playback

Head

“Upper”

or

“Lower”

and

Record

“Head

“Upper”

or

“Lower”

are

illuminating.

In

order

not

to

give

damages

onto

the

head

surfaces,

push

both

of

slide

knobs

of

the

Gauge

to

away

from

the

heads,

then

return

them

to

the

original

place

to

be

in

contact

with

record

head

and

playback

head

surfaces

after

Play

mode

is

securely

locked.

(6)

Beacon

Playback

Head

*“‘Lower’’

will

light

on

when

height

.

adjustment

screw

(PH)

turned

counterclockwise

but

Play-

back

Head

“‘Upper’

when

clockwise.

Adjust

so

that

both

“Upper”

and

“Lower”

will

light

on

even

when

you

move

the

slide

knob

away

from

the

heads

and

then

return

it

to

the

original

place.

(7)

Same

procedures

will

apply

to

the

Beacons

Record

Head

“Upper”

and

“Lower’’,

except

for

the

height

adjustment

screw

(RH).

(8)

Set

the

cassette

deck

in

Stop

mode

and

fit

both

of

the

serrated

Height

Gears.

Then

set

the

cassette

deck

again

in

Play

mode

and

insure

all

of

the

4

Beacons

are

illuminating.

If

not,

(4)

through

(7)

will

have

to

be

repeated

till

satisfactory

results

are

obtained.

(9)

Mount

the

pad

lifter

on

the

playback

head.

3.2.

Head

Base

Stroke

Check

Remove

the

Cover

Plate

Ass’y.

Refer

to

Fig.

3.2.

Note:

Before

you

conduct

this

adjustment,

adjust

with

a

“Tilt

Check

Gauge

S”

to

insure

freedom

from

tilt

on

the

play-

back

head

and

record

head.

(1)

Load

a

Stroke

Check

Gauge

S

in

the

cassette

deck,

(2)

Move

Record

Head

Indicator

and

Playback

Head

Indicator

to

the

direction

of

arrow

mark

“A”

with

your

finger

tip

and

then

set

the

cassette

deck

in

Play

mode.

Then

slowly

release

the

Indicators

and

insure

whether

each

of

the

Indicators

is

in

contact

with

record

and

playback

heads.

(3)

Check

to

insure

whether

the

line

“P”

on

the

Playback

Head

Indicator

meets

the

central

line

on

the

Indicator

Plate.

(4)

Check

to

insure

whether

the

line

“P”

on

the

Playback

Head

Indicator

locates

between

the

2

lines

on

the

Record

Head

Indicator,

thus

check

can

be

made

on

record

head

stroke.

3.3.

Erase

Head

Stroke

Adjustment

and

Tape

Guide

Height

Check

Remove

the

Head

Mount

Base

Ass’y

and

the

Cover

Plate

Ass’y,

Refer

to

Fig.

3.3.

(1)

Erase

Head

Stroke

Adjustment

(a)

Load

a

Tape

Guide

Height

Check

Gauge

S

in

the

cassette

deck,

(b)

Set

the

cassette

deck

in

Play

mode,

thus

check

can

be

made

on

erase

head

stroke

through

the

EH

Stroke

Indicator,

(ec)

Check

to

insure

whether

the

erase

head

surface

is

aligned

with

red

line

on

the

EH

Stroke

Indicator.

If

not,

adjust

the

erase

head

stroke

by

loosening

screw

A

that

assembles

erase

head

with

erase

head

plate.

(d)

After

completion

of

adjustment,

screw

A

shall

be

locked

with

lock

tight

paint,

(2)

Supply

Tape

Guide

Height

Check

(a)

Load

a

Tape

Guide

Height

Check

Gauge

§

in

the

cassette

deck,

(b)

Set

the

cassette

deck

in

Play

mode,

(c)

Slide

the

Supply

Tape

Guide

Check

Bar

down

against

the

supply

tape

guide,

and

check

to

insure

that

the

Supply

Tape

Guide

Check

Bar

is

accepted

by

the

supply

tape

guide.

(3)

Take-up

Tape

Guide

Height

Check

(a)

Load

a

Tape

Guide

Height

Check

Gauge

S

in

the

cassette

deck.

(b)

Set

the

cassette

deck

in

Play

mode,

(c)

Slide

the

Take-up

Tape

Guide

Check

Bar

down

against

the

take-up

tape

guide,

and

check

to

insure

that

the

Take-up

‘Tape

Guide

Check

Bar

is

accepted

by

the

take-up

tape

guide.

Height

Gear

Stopper

(RH)

Height

Geor

(RH)

Height

Geor

(PH)

Play

Mode

Fig,

3.3

Height

Adj,

Screws(PH!

Take-up

Tape

Guide

Check

Bar

3.4.

Erase

Head

Height

and

Tilt

Adjustment

Refer

to

Fig.

3.4.

qd)

(2)

(3)

(4)

(5)

Remove

the

Cassette

Case

Ass’y,

Head

Mount

Base

Ass’y

and

Cover

Plate

Ass’y.

Load

an

EH

Tilt

Check

Gauge

S

in

the

cassette

deck.

Set

the

cassette

deck

in

Stop

mode.

Check

to

insure

whether

one

of

the

3

Beacons

is

illuminating.

Look

down

the

mirror

and

slowly

turn

the

Screw

“Height”

counterclockwise

(or

clockwise)

so

that

the

two

horizontal

lines

on

the

mirror

will

become

superposed

on

the

line

(in

different

color)

of

the

erase

head,

and

check

to

insure

whether

the

first

Beacon

is

illuminating.

Turn

Screw

“Tilt”

counterclockwise

(or

clockwise)

to

light

on

the

second

Beacon,

Excessive

turing

will]

cause

the

first

(6)

(7)

(8)

Beacon

to

light

off,

Adjustments

of

Screw

“Tilt”

will

there-

fore

be

conducted

till

both

of

the

first

and

the

second

Beacons

iJuminate.

Turn

Screw

“Azimuth”

counterclockwise

(or

clockwise)

to

light

on

the

third

Beacon,

Excessive

turning

will

cause

either

the

first

or

the

second

Beacon

to

light

off,

and

therefore

adjust

Screw

“‘Azimuth’’

until

all

of

the

3

Beacons

illuminate.

Check

to

insure

whether

the

horizontal

line

on

the

mirror

corresponds

to

that

on

the

erase

head.

If

not,

(4)

through

(7)

will

have

to

be

repeated

till

satisfactory

results

are

obtained,

After

completion

of

adjustment,

3

pes.

of

screws

shall

be

locked

with

lock

tight

paint.

Note:

Before

use

of

this

gauge,

check

to

insure

freedom

from

dust

Fig.

3.4

3.5.

Playback

Head

and

Record

Head

Height

Adjustment

and

(2)

Azimuth

Alignment

(a)

Refer

to

Fig.

3.5.

(b)

(1)

(a)

b)

(ec)

(a)

(e)

(f)

Playback

Head

Height

Adjustment

and

Azimuth

Alignment

Set

the

Monitor

switch

to

Tape,

then

connect

a

VTVM

to

the

Output

Jacks,

Load

a

1

kHz

Track

Alignment

Tape,

then

set

the

cassette

deck

in

Play

mode,

Turn

the

PH

Height

Gear

until

the

outputs

of

both

channels

become

minimum.

Load

a

15

kHz

Azimuth

Tape,

then

set

the

cassette

deck

in

Play

mode,

Turn

the

PH

Azimuth

Alignment

Screw

until

the

outputs

of

both

channels

become

maximum,

Repeat

above

steps

(b)

through

(e)

one

or

two

times

to

obtain

optimum

performance.

PHHeight

Adjustment

PH

Azimuth

Alignment

(c)

(a)

(e)

69)

(8)

or

dirts,

or

overflow

in

the

groove

of

the

erase

head

surface.

Record

Head

Height

Adjustment

and

Azimuth

Alignment

Set

the

cassette

deck

in

Stop

mode.

Set

the

Monitor

switch

to

Tape,

Eq.

switch

to

70

és

and

Tape

Selector

switch

to

ZX.

Load

a

reference

ZX

tape

and

connect

a

VTVM

to

Output

Jacks,

Feed

in

400

Hz

(0

dB)

to

the

Input

Jacks,

Set

the

cassette

deck

in

Record

and

Play

mode

and

turn

the

RH

Height

Gear

until

the

outputs

of

both

channels

become

maximum,

Feed

in

15

kHz

(—20

dB)

to

the

Input

Jacks

and

turn

the

RH

Azimuth

Alignment

Screw

until

the

outputs

of

both

channels

become

maximum.

Repeat

(d)

to

(f)

one

or

two

times

to

obtain

optimum

per-

formance,

RH

Height

Adjustment

RH

Azimuth

Alignment

Fig.

3.5

3.6,

Pressure

Adjustment

of

Take-up

Pressure

Roller

Refer

to

Fig.

3.6.

(1)

Set

the

cassette

deck

in

Play

mode,

(2)

Measure

the

torque

of

the

Take-up

Pressure

Roller

and

check

whether

the

torque

is

in

a

range

of

320

+50

g-cm.

(3)

If

torque

is

out

of

the

range,

correct

it

by

changing

the

instal-

lation

point

of

the

Pressure

Roller

Spring.

Fig.

3.6

3.7.

Tape

Travelling

Check

Load

and

playback

a

Tape

Travelling

Cassette

and

check

the

following:

(1)

Tape

is

in

contact

with

heads

sufficiently.

(2)

Tape

waving

is

small

on

the

heads

and

pressure

rollers.

(3)

Tape

is

free

from

waving

or

slippage

from

the

tape

guides.

3.8.

Eject

Damper

Adjustment

Refer

to

Fig.

3.8.

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

Adjustment

Screw.

Fig.

3.8

3.9.

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.

3.10.

Tape

Speed

Adjustment

Refer

to

Fig,

3.9.

(1)

Set

the

Pitch

Control

Knob

on

the

Front

Panel

to

its

mechan-

ical

center

position.

(2)

Connect

a

frequency

counter

to

the

Output

Jacks,

(3)

Load

a

3

kHz

Speed

and

Wow/Flutter

Tape

and

play

it

back,

(4)

Adjust

VR101

on

the

Motor

P.C.B.

Ass’y

to

obtain

3,000

Hz

on

the

frequency

counter.

CCW:

Motor

drives

fast.

Cw:

Motor

drives

slowly.

a

2

a

2

Q

5

Dd

Increase

ar

Motor

PC.8.

Assy

Decrease

Fig.

3.9

3.11.

Lubrication

The

tape

transport

is

of

a

lubrication-free

type

mechanism.

When

the

following

parts

are

replaced,

apply

the

specified

lubricant.

(1)

Molykote

@)

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,

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

4.

PARTS

LOCATION

FOR

ELECTRICAL

ADJUSTMENT

Main

PC.B.

VRI01

VR201

Playback

Level

6)

VR60I

rPeaking

Reel

Motor

Speed

(Play)

L102

L204

MPX

Filter

T

_

:

Bias

Trop

(Record)

TP202©)

TP201@

TP101I®

TP102©

L108

[oe]

L104

VR202

VR204

&

s[9]

©L

(QL

vazos

CL

EX

x

zx

Record

Level

3

18)

19

vR102

VRI03

VRI04

Meter

Amp.P

C.B.

Tape

Switch

P

C.B.

Fig.

4

5.

ELECTRICAL

ADJUSTMENTS

Notes:

1.

Electrical

adjustment

should

be

performed

after

mechanical

adjustment

is

completed.

2.

Before

adjustment,

set

the

Bias

Tune

control

and

the

Pitch

control

on

the

Front

Panel

to

their

mechanical

center

positions,

5.1.

Adjustment

Instructions

REMARKS

1,

Set

the

Pitch

Control

to

its

mechanical

center

position.

2.

Adjust

VR101

to

obtain

3

kHz

+0.5%

on

the

frequency

counter,

Output

Jacks

MPX

SW

-—ON

Input

Jacks

Play

back

1

kHz

Track

Monitor

SW

—

Tape

VTVM

to

Eq,

SW

—

70

us

Alignment

B

Tape

Output

Jacks

=|

Dolby

NR

SW

—

OFF

MPX

SW

—

OFF

Playback

Head

Track

Playback

Monitor

SW

—

Tape

Eq.

SW

—

70

us

Dolby

NR

SW

—

OFF

MPX

SW

—

OFF

VTVM

to

Output

Jacks

Head

15

kHz

Azimuth

Tape

Evpene

400

Hz

Level

VTVM

to

Calibration

|

T@Pe

Output

Jacks

Same

as

above

400

Hz

Level

Playback

Frequency

Monitor

SW

—

Tape

Frequency

|

Response

Tape

|

yryn

to

Tape

SW

—

SX

15

kHz

PB

t

Frequency

Response

Tape

20

kHz

PB

Frequency

Response

Tape

Output

Jacks

Eq.

SW

—

70us

Dolby

NR

SW

—

OFF

MPX

SW

—

OFF

Response

Adjustmen

SIGNAL

OUTPUT

ADJUST-

STEP

ITEM

SOURCE

|

CONNECTION

MODE

MENT

3

kHz

Speed

1

Tape

Speed

|

and

olson

Play

back

Motor

P.C.B.

Adjustment

|

Wow/Flutter

Output

Jacks

Eq.

SW

—

70

us

VR101

Tape

P

Meter

Amp.

Meter

Level

|

400

Hz

to

VTVM

to

F

a

2

Calibration

|

Input

Jacks

Output

Jacks

Monitor

SW

—

Source

is

108.VR

208

r

5.

+

2

:

19

kHz

+100

Monitor

SW

—

Source

A

MPX

Filter

VTVM

to

Main

P.C.B.

3

Adjustment

Hz

to

Dolby

NR

SW

—

OFF

L102,L202

3.

PH

Height

Gear

Playback

Head

Azimuth

Alignment

Screw

Main

P.C.B.

VR101,VR201

Main

P.C,B.

R109,R209

R110,R210

1.

Set the

Output

Level

control

to

max.

2.

Feed

in

400

Hz,

then

adjust

the

Input

Level

controls

to

obtain

1.0

V

~—4

dB

on

the

VTVM.

3.

Adjust

VR108

(VR208)

so

that

the

0

dB

segment

of

the

level

meter

starts

to

il-

luminate,

Adjust

the

Input

Level

control

to

obtain

1.0

V

+1

dB

on

the

VTVM

and

check

to

insure

that

the

upper

segment

of

the

O

dB

segment

starts

to

illuminate.

Set

the

Output

Level

control

to

max,

.

Adjust

the

Input

Level

controls

to

obtain

1

V

on

the

VTVM.

Set

the

MPX

Filter

switch

to

ON,

then

adjust

L102

(L202)

to

obtain

the

minimum

reading

on

the

VTVM

(the

minimum

read-

ing

will

be

less

than

—30

dB),

Adjust

the

PH

Height

Gear

to

obtain

minimum

readings

for

both

channels

on

the

VT

VM.

Refer

to

“Playback

Head

Height

Adjustment

and

Azimuth

Alignment”

in

item

3.5,

Adjust

the

Playback

Head

Azimuth

Alignment

Screw

to

obtain

maximum

readings

of

both

channels

on

the

VTVM,

Refer

to

“Playback

Head

Height

Adjustment

and

Azimuth

Align-

ment”

in

item

3.5.

Note:

Repeat

steps

4

and

5

one

or

two

times

to

obtain

optimum

performance,

1.

Set

the

Output

Level

control

to

max.

2.

Adjust

VR101

(VR201)

to

obtain

1.0

V

on

the

VTVM.

.

Load

a

400

Hz

level

tape

and

play

it

back.

Adjust

the

Output

Level

control

to

a

certain

level

(0

dB

for

example),

2,

Load

10

kHz,

15

kHz

and

20

kHz

PB

fre-

quency

response

tapes

and

adjust

the

play-

back

head

azimuth

to

obtain

maximum

levels

on

the

VTVM

with

each

tape.

Short

R109

(R209)

and/or

R110

(R210)

to

obtain

the

following

levels

against

the

level

for

the

400

Hz

level

tape.

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

‘Playback

Frequency

Response

Adjustment”’

in

item

5,2.

3.

Conduct

step

5

“Playback

Head

Azimuth

i

ent’’.

VTVM

across

the

additional

Record,

Pause

0.1

2

resistor

Monitor

SW

—

Source

Oscillation

Frequency

and

Tape

SW

—

ZX

and

Erase

Frequency

Eq.

SW

—

70

us

Current

Counter

to

Dolby

NR

SW

—

OFF

Adjustment

CN3-lon

Tape

|MPX

SW

—-OFF

Switch

P.C.B,

Record

Amplifier

Pha

Equalizer

|

(—20

dB)

to

Adjustment

|

put

Jacks

VTVM

to

TP101,

TP201

on

Main

P.C.B.

Same

as

above

Bias

Trap

Adjustment

|

Remove

(Record

input

signals

VTVM

to

TP102,

TP202

on

Main

P.C.B.

Same

as

above

Tape

Switch

P.C.B.

T301

R301,R302

Main

P.C,B.

L104,L204

1,

Connect

an

additional

0.1

2

resistor

in

series

to

the

Erase

Head,

then

connect

a

VTVM

across

the

resistor.

2.

Adjust

T301

to

obtain

105

kHz

on

the

fre-

quency

counter,

3.

Check

the

erase

current

by

the

VTVM.

Erase

current

will

be

in

a

range

of

310

mA

to

400

mA

(typically

approx.

350

mA).

If

erase

current

is

not

sufficient,

increase

it

by

shoring

either

R301

or

R302.

4.

After

completion

of

the

erase

current

adjustment,

re-check

the

bias

oscillation

frequency.

.

Remove

the

additional

0.1

©

resistor.

5

1.

Remove

the

bias-cut-jumper

from

the

dip

side

of

the

Tape

Switch

P.C.B.

Ass’y.

2,

Adjust

L104

(L204)

to

obtain

approx.

+16

dB

at

23

kHz

on

the

VTVM.

3.

Re-solder

the

bias-cut-jumper.

Main

P.C.B.

L105,L205

Adjust

L105

(L205)

to

obtain

minimum

read-

ing

on

the

VT

VM.

Record,

Playback

Monitor

SW

—

Tape

SW

—

ZX

Eq.

SW

—

70

us

Dolby

NR

SW

—

OFF

MPX

SW

—

OFF

VTVM

to

Output

Jacks

400

Hz

(0

dB)

to

Input

Jacks

11

Head

Height

RH

Height

Gear

Adjustment

to

Record

<

15

kHz

(—20

Record

Head

12

Head

dB)

to

Input

bra

eis

.

ck

Same

as

above

Azimuth

Jacks

urpUswacks

Alignment

Screw

Alignment

1.

2.

3.

4,

Main

P.C.B.

(Level)

Record,

Playback

ZX:

Tone

—

400

Hz/

VR104,VR204

15

kHz

Sx:

Record

Monitor

SW

—

Source/|

VR103,VR203

7.

Level

400

Hz

and

Tape

EX:

Calibration

as

ae

VTVM

and

Tape

SW

—

BxISe!

VR102,VR202

18

|

and

10

kHz/20

Dig

rion

Meer

ng

sw

=

70

ps

Tape

Switch

Recording

|

x+12

(—20

dp)

|

*

Output

Jacks

(ZX/SX)

|P.C.B

8

Adjustment

|

‘©

Input

Jacks

120

us

(EX)|

(Biss)

Dolby

NR

SW

—

X:

C-Type/B-Type/

OFF

MPX

SW

—

OFF

VR107,VR207

SX:

VR106,VR206

EX:

VR105,VR205

1/11,

Record,

Playback

Monitor

SW

—

Source/

Tape

SW

—

ZX/SX/EX

Overall

400

Hz

(0

dB)

d

20

Hz

to

A

Frequency

|

22

VTVM

to

_

Main

P.C.B.

14

[Response

|

20072

4.

[Output

Jacks

|

Ba.

SW

(2kisxy

|

1104,L204

é

Adjustment

|

Faout

Jacks

120

us

(EX)

:

Dolby

NR

SW

—

OFF

MPX

SW

—

OFF

7

8

SIGNAL

OUTPUT

ADJUST-

sree

|

em

SOURCE

CONNECTION

MODE

MENT

REMARKS

Adjust

the

RH

Height

Gear

to

obtain

maximum

readings

of

both

channels

on

the

VTVM.

Refer

Azimuth

Alignment”

in

item

3.5,

Adjust

the

Record

Head

Azimuth

Alignment

Screw

to

obtain

maximum

readings

of

both

channels

on

the

VT

VM.

Refer

to

“Record

Head

Height

Adjustment

and

Azimuth

Alignment”

in

item

3.5,

Note:

Repeat

steps

11

and

12

one

or

two

times

Adjustment

should

be

made

in

the

order

of

ZX,

SX

and

EX.

.

Adjust

Record

Cal!

VR104

(VR204)

for

-

Feed

in

400

Hz

(0

dB),

then

record

and

play

.

Check

to

insure

whether

the

total

harmonic

.

If

above

is

not

sufficient,

repeat

6

to

14

till

.

Set

the

Monitor

switch

to

Source.

-

Conduct

step

13

“Record

Level

Calibration

.

If

above

is

not

sufficient,

precise

re-adjust-

“Record

Head

Height

Adjustment

and

to

obtain

optimum

performance.

Set

the

Monitor

switch

to

Source

and

Dolby

NR

switch

to

C-Type.

Feed

in

400

Hz,

then

set

the

Input

Level

controls

to

obtain

0

dB

(1

V)

on

the

VTVM.

Set the

Monitor

switch

to

Tape.

Load

a

reference

ZX

tape,

reference

SX

or

SX-E

(for

BX-300E)

tape

and

reference

EXII

tape.

ZX,

VR103

(VR203)

for

SX

and

VR102

(VR202)

for

EX

to

center

position,

it

back.

Adjust

Bias

VR107

(VR207)

for

ZX,

VR106

(VR206)

for

SX

and

VR105

(VR205)

for

EX

to

obtain

the

maximum

readings

on

the

VTVM.

Feed

in

15

kHz

(—20

dB),

then

adjust

Bias

VR107

(VR207),

VR106

(VR206)

and

VR105

(VR205)

to

obtain

the

same

readings

as

source

monitor

levels

on

the

VTVM.

Feed

in

400

Hz

(0

dB),

then

adjust

Record

Cal,

VR104

(VR204),

VR103

(VR203)

and

VR102

(VR202)

to

obtain

0

dB

on

the

VTVM.

Repeat

above

7

and

8

two

or

three

times

to

obtain

optimum

performance.

Set

the

Dolby

NR

switch

to

OFF.

Feed

in

10

kHz

(—20

dB)

and

20

kHz

(—20

dB),

then

record

and

play

them

back,

Check

to

insure

that

the

levels

are

within

—20

dB

+3

dB

against

the

levels

in

Dolby

NR

C-Type.

Set

the

Dolby

NR

switch

to

B-Type.

Feed

in

10

kHz

(—20

dB)

and

20

kHz

(—20

dB),

then

record

and

play

them

back.

Check

to

insure

that

the

levels

are

within

—20

dB

+3

dB

against

the

levels

in

Dolby

NR

OFF.

distortion

is

less

than

0.9%

for

ZX

tape

and

1,0%

for

SX/SX-E

and

EXII

tapes.

satisfactory

results

are

obtained.

Feed

in

400

Hz

(0

dB)

and

adjust

the

Input

Level

controls

to

obtain

0

dB

(1

V)

on

the

VTVM.

pha

the

Generator

output

level

to

—20

B.

Set

the

Monitor

switch

to

Tape,

then

record

and

play

it

back.

Feed

in

20

Hz

to

20

kHz

(—20

dB),

and

check

to

insure

whether

the

output

levels

are

within

—20

dB

+3

dB.

If

above

is

not

sufficient,

adjust

L104

(L204)

to

obtain

approx.

—20

dB

on

the

VTVM

at

20

kHz.

and

Recording

Bias

Current

Adjustment’,

ment

of

step

7

“Playback

Frequency

Response’’,

replacement

of

Playback

Head

or

Record

Head,

check

on

item

3.7

“Tape

Travelling

Check’

will

be

required.

5.2,

Playback

Frequency

Response

Adjustment

The

peaking

portion

of

the

equalization

curve

compensates

the

Figs,

5.1

and

5.2

show

the

playback

amp.

circuit

for

adjusment

gap

loss

of

the

playback

head.

Peaking

level

is

varied

by

the

short

and

the

playback

equalization

curve.

circuit

of

R109

(R209)

and/or

R110

(R210)

on

the

Main

P.C.B.

This

adjustment

will

be

required

if

playback

level

is

not

sufficient

Ass’y.

during

playing

back

a

20

kHz

PB

frequency

response

tape.

R109

R110

L101

(R209)

(R210)

ar

laaiaass

390

3=

68

Play

back

Head

Fig.

5.1

GAIN

(dB)

approx.

2dB

approx.

2d8

approx.

2dB

FREQUENCY

(Hz)

Fig.

5.2

Nakamichi BX-300 Bedienungsanleitung

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