Tandberg Tcd 310 User manual

Service

Manual

Cassette

Deck

TANDBERG

CONTENTS

lz

Dsmanthings

.

24

-.teaw.

ah.

OR ee

3

1.1

Removal

of

top

plate.............

3

1.2

Removal

of

inner

top

plate

........

3

1.3

A

note

on

reassembling

...........

3

2.

Regular

maintenance

...............-

4

Peas

CHANTS

ok

cet,

Sees,

Gees

ee

4

2

eoatssiney

8.

feet

ae

ee

ae

APOBAS

GATIONS.

grec’.

Cie

ae

wane

ey

a

3.

Mechanical

servicing

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

5

3.1

Microswitches

MS

1

and

MS

2......

5

3.2

Tape

path

adjustments

...........

5

Sealy

OUDMIME:

[ies

cn:

.

aie

=

oe

D

See

DeTaON

s

atid.

Tas

ous

oe

ee

6

3.3

Replacing

the

drive

belt...........

8

GPa

CAssene

AMM.

.

ms

he

eee

10

3.5

Pinch

roller

solenoid..............

10

DFO

WHalISe,

CONUEON

..

eat

Bete

ee

11

3.7

Adjusting

the

position

of

a

reel

motor

11

5.8

Salvaging

tangled

tape

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

11

4.

Motor

and

solenoid

circuits

...........

12

4,1

Solenoid

operating

circuit

.........

12

4,2

Motor

control

circuits

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

13

4.3

Control

of

motor

voltages

.........

13

5.

Electrical

adjustments

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

14

6.

Circuit

diagrams....................

16

1.

DISMANTLING

Bal

REMOVAL

OF

TOP

PLATE

1.

Remove

the

plastic

lid

from

the

cassette

com-

partment,

and

push

the

compartment

down

to

closed

position.

2.

Remove

the

RECORD

LEVEL

buttons

(A).

Remove

the

3

screws

on

the

top

plate

(B)

and

the

3

screws

at

the

top

of

the

rear

plate

(C).

US-version

only:

Remove

the

nuts

from

the

microphone

sockets

(D).

3.

Grip

the

left

edge

of

the

cassette

compartment

aperture

with

your

fingers

(indicated

with

arrows

on.

the

drawing).

Remove

the

top

plate

by

lifting

the

rear

edge

first,

and

pulling

the

plate

away

from

the

recorder.

1.2

REMOVAL

OF

INNER

TOP

PLATE

The

inner

top

plate

with

indicators

and

volume

controls

can

be

lifted

to

the

vertical

position

to

give

access

to

the

electrical

parts.

1.

Remove

the

plastic

cover

of

the

indicators.

2.

Remove

the

left

side

wall

by

unscrewing

the

two

black

screws.

3.

Push

the

operating

buttons

(E)

out

to

the

left.

4.

Remove

the

plastic

arm

(F)

from

the

PAUSE

switch.

5.

Unscrew

the

6

screws

(G).

6.

Unhook

the

eject

interlock

arm

from

the

moving

plate

on

the

switch

bracket.

7.

Grip

the

right

edge

of

the

inner

top

plate

and

lift

it

carefully

to

vertical

position.

1.3

ANOTE

ON

REASSEMBLING

When

reassembling

make

sure

that

the

hooks

(J)

on

the

operating

buttons

are

hooked

onto

the

plastic

arms

on

the

switches.

Also

make

sure

that

the

eject

interlock

arm

is

hooked

onto

the

moving

plate

on

the

eject

switch

bracket.

Cassette

compartment

Plastic

cover

Inner

top

plate

Left

side

wall

Oe

ec

OCpoocoo

oF

(ohkenonek

chutenekokekenes

i

|

j

Profile

of

operating

button,

zZ

2.1

CLEANING

The

parts

of

the

cassette

deck

that

are

in

contact

with

the

tape

surface

should

be

cleaned

regularly,

otherwise

the

sound

quality

will

be

greatly

reduced.

Cleaning

of

capstans

and

pinch

rollers

is

particularly

important

to

avoid

wow

and

flutter.

If

the

cassette

deck

is

used

every

day,

cleaning

should

be

performed

at

least

once

a

month.

The

cleaning

can

be

done

with

cotton

wool

or

a

piece

of

flannel

wrapped

around

a

small

stick

and

moistened

with

pure

alcohol

or

methylated

spirit.

A

kit

intended

for

this

purpose,

Tandberg

Profes-

sional

Tape

Head

Cleaner”’,

is

available.

NOTE!

Do

not

use

solvents,

such

as

acetone

or

trichlor-

ethylene,

as

these

may

damage

the

heads.

How

to

clean

1.

Press

the

EJECT

button,

and

remove

the

plastic

lid

from

the

cassette

compartment.

2.

Push

the

cassette

compartment

down

to

closed

position.

3.

Clean

the

record/playback

head

(A),

erase

head

(B),

tape

guide

(C),

capstans

(D)

and

pinch

rollers

(E).

Do

not

use

too

much

cleaning

liquid

on

the

pinch

rollers,

and

dry

them

afterwards.

DO

NOT

USE

ANY

SHARP

OBJECTS

WHEN

CLEANING.

DO

NOT

TOUCH

THE

ADJUST-

MENT

SCREWS.

4.

Check

the

surrounding

area

for

dust

and

de-

posits

from

the

tape.

Clean

if

required.

Cleaning

should

be

performed

both

before

and

after

adjustments.

2.2

DEGAUSSING

A

marked

increase

in

background

noise

from

the

tape

may

indicate

that

the

heads

or

other

parts

in

the

tape

path

should

have

the

residual

magnetism

removed

(degaussing).

If

required,

degaussing

should

be

carried

out

as

follows.

Switch

off

the

deck.

Remove

the

cassette

from

the

deck.

Remove

the

plastic

4

REGULAR

MAINTENANCE

eco

he

fe

"a

se

Neen

f

PW

A

eaaeem

Pei

Rineasy,

Parts

to

be

cleaned

cassette

compartment

lid

and

move

the

de-

gausser

slowly

past

each

one

of

the

metal

parts

normally

in

contact

with

the

tape.

Take

great

care

not

to

let

the

degausser

touch

the

heads

or

metal

parts

in

the

tape

path.

Do

not

switch

off

the

de-

gausser

until

it

is

at

least

3

ft

from

the

deck.

Degaussing

should

be

performed

both

before

and

after

adjustments.

2.3

LUBRICATION

The

capstan

motor

and

the

reel

motors

may

require

lubrication

from

time

to

time.

The

interval

between

each

lubrication

should

be

at

least

3000

hours

of

operation.

Use

the

following

types

of

oil:

Capstan

motor:

ANDEROL

465

from

Tenneco

Chemicals,

U.S.A.,

or

oil

supplied

by

Tandberg.

Reel

motors:

NUTO

H36

(also

called

SPINESSO

34)

from

Esso.

NOTE!

Use

only

one

drop

of

oil

for

each

motor.

3.

MECHANICAL

SERVICING

3.1

MICROSWITCHES

MS

1

AND

MS

2

Pinch

rollers

released:

MS

1:

Check

that

there

is

a

gap

of

about

1

mm

between

the

connecting

arm

and

the

middle

leaf

of

the

switch

(see

figure).

MS

2:

Check

that

the

two

leaves

of

the

switch

are

pressed

together

between

the

solenoid

operating

lever

and

the

bracket.

Adjust

by

bending

the

bracket.

Pinch

rollers

operated:

MS

1:

Check

that

the

left

and

the

middle

leaf

are

pressed

together.

MS

2:

Check

that

the

switch

is

open.

3.2

TAPE

PATH

ADJUSTMENTS

The

following

equipment

is

needed:

—

An

ordinary

high

quality

cassette

which

has

been

cut

open

so

that

the

tape

is

visible

(see

figure).

—

Tandberg

test

tape

No.

23

(azimuth

test).

For

really

extensive

adjustments

—

for

example

if

several

parts

in

the

tape

path

are

replaced

—

a

Tandberg

Adjustment

Plate

may

be

needed.

Such

adjustments

should

be

carried

out

by

a

Tandberg

representative.

3.2.1

Outline

of

the

adjustment

procedure

Insert

an

open

cassette

and

set

the

deck

to

PLAY.

Check

that

the

tape

does

not

”climb”’

on

the

capstans

and

is

not

bent

or

folded

at

the

tape

guides.

Also

check

that

the

tape

does

not

”bulge”

at

the

heads

(’*bulging”

indicates

wrong

azimuth

adjustment

of

the

heads).

When

viewed

from

above

the

tape

should

be

seen

as

an

almost

invisible

line.

Also

check

that

the

top

of

the

erase

head

is

flush

with

the

top

edge

of

the

tape.

The

erase

head

should

not

be

visible

above

the

tape.

If

erratic

tape

motion

is

observed,

try

to

eliminate

it

by

turning

the

adjustment

screws

for

heads

or

pinch

rollers.

Insert

a

Tandberg

test

tape

No.

23

and

adjust

with

the

screw

(AZ)

on

the

record/playback

head

to

maximum

output

signals

on

both

OUTPUT

sockets.

The

difference

between

the

tracks

should

be

less

than

4

dB.

(Details:

see

Tandberg

Adjustment

Plate

3.2.2

Details

of

adjustment

procedure

@

Pinch

rollers.

Parallelity.

Move

the

mounting

plate

inwards

so

that

the

pinch

rollers

almost

touch

the

capstans.

Adjust

with

the

screws

(P)

so

that

both

rollers

are

parallel

with

the

capstans.

A

white

piece

of

paper

can

be

inserted

behind

the

pinch

roller

and

capstan

to

make

it

easier

to

see

the

gap

between

them.

Height.

Insert

the

open

cassette.

Move

the

mounting

plate

inwards

and

check

that

the

tape

fits

exactly

into

the

tape

guide

on

pinch

roller

1.

Adjust

with

the

two

screws

(H)

if

necessary

(turn

both

screws

equal

amounts).

Also

turn

the

azimuth

screw

(AZ)

correspondingly

in

the

opposite

direction

to

keep

the

roller

roughly

in

correct

azimuth

position.

Adjust

pinch

roller

2

to

corresponding

height.

This

adjustment

is

not

critical.

Azimuth.

Set

the

cassette

deck

to

PLAY

and

check

that

the

tape

does

not

”climb”

on

the

capstans.

If

necessary,

adjust

with

the

screws

(AZ).

Check

again

that

the

tape

is

not

bent

or

folded

at

the

tape

guide

of

pinch

roller

1.

Also

check

the

parallelity

again.

Height

and

azimuth

can

also

be

adjusted

by

means

of

a

Tandberg

Adjustment

Plate.

The

pinch

rollers

are

then

checked

against

the

tabs

marked

A

and

B

in

the

figure.

(A

special

adjustment

plate

for

the

pinch

roller

shafts

can

also

be

used).

Pinch

roller

operation.

Remove

the

cassette

and

move

the

mounting

plate

inwards.

Check

that

both

pinch

rollers

meet

the

capstans

at

exactly

the

same

time

(the

pinch

rollers

will

start

rotating

when

they

touch

the

capstans).

If

required,

adjust

with

the

eccentric

screw

as

shown.

@

Erase

head

The

position

of

the

erase

head

is

adjusted

by

turning

the

screws

on

the

head

mounting

plate

(see

top

figure

).

Preadjustment

of

head

mounting

plate.

Adjust

with

the

screws

(H)

and

(AZ)so

that

the

head

mounting

plate

is

parallel

with

the

underlying

mounting

plate.

The

gap

between

them

should

be

approx.

1

mm.

To

check

this,

the

right

chassis

plate

must

be

removed.

6

Height

Azimuth

Parallelity

Adjustment

screw

for

pinch

roller

operation

Preadjustment

of

head

mounting

plate

Adjustment

of

erase

head.

Insert

the

open

cassette

and

move

the

mounting

plate

inwards.

Adjust

with

the

screws

(H)

and

(AZ)

so

that

the

top

of

the

erase

head

is

flush

with

the

top

edge

of

the

tape.

The

front

of

the

erase

head

should

be

parallel

with

the

tape.

Set the

deck

to

PLAY.

Check

that

the

erase

head

is

not

visible

above

the

tape,

and

that

the

tape

does

not

bulge”

at

the

head.

Keep

the

head

mounting

plate

parallel

with

the

underlying

mounting

plate.

The

screws

(H)

must

not

be

unscrewed

too

far,

as

the

spring

under

the

head

mounting

plate

will

then

prevent

the

mounting

plate

from

moving

freely.

An

Adjustment

Plate

can

also

be

used.

In

this

case

the

top

of

the

erase

head

should

be

flush

with

tab

D.

The

front

of

the

erase

head

should

be

parallel

with

the

tab.

M@

Record/playback

head

The

position

of

the

record/playback

head

is

adjusted

by

turning

the

screws

on

the

head

bracket.

Do

not

touch

the

adjustment

screws

for

the

head

mounting

plate.

It

is

assumed

that

the

head

mounting

plate

has

already

been

correctly

adjusted

Height

and

parallelity.

Insert

the

open

cassette

and

move

the

mounting

plate

inwards.

Adjust

with

the

screws

(H)

and

(P)

so

that

the

tape

fits

exactly

into

the

tape

guide

of

the

head.

The

front

of

the

head

should

be

parallel

with

the

tape.

Set

the

deck

to

PLAY.

Check

again

that

the

tape

is

not

bent

or

folded

at

the

tape

guide,

and

does

not

*bulge’’

at

the

head.

Azimuth.

Insert

a

Tandberg

test

Tape

No.

23

(6,300

Hz

azimuth

test).

Connect

a

voltmeter

to

each

OUTPUT

socket

and

set

the

deck

to

PLAY.

Adjust

with

the

screw

(AZ)

to

maximum

output

signals

with

no

more

than

4

dB

difference

between

the

tracks

(adjust

to

best

compromise).

Check

the

height

and

parallelity

again,

and

re-

adjust

if

necessary.

If

readjustments

are

made,

the

azimuth

must

be

checked

again.

If

an

Adjustment

Plate

is

used,

the

parallelity

must

be

checked

against

tab

F,

and

the

height

against

tab

E.

Do

not

turn

the

screws

while

the

tape

guide

of

the

head

touches

tab

E

as

this

may

cause

bending

of

the

tape

guide.

Tracking

control.

Insert

an

ordinary

cassette

and

record

a

signal

on

both

tracks.

Then

turn

the

cassette

around

and

set

the

deck

to

PLAY.

Listen

for

crosstalk

on

the

recorded

piece

of

tape.

Head

mounting

plate

Right

chassis

plate

Adjustment

screws

for

erase

head

Tandberg

Adjustment

Plate

Adjustment

screws

for

record/playback

head

Open

cassette

3.3.

REPLACING

THE

DRIVE

BELT

Before

starting

this

operation

remove

the

top

plate

and

the

cassette

compartment

lid.

1.

Wind

a

piece

of

sellotape

a

few

times

around

each

capstan

(see

fig.).

This

is

done

to

ensure

that

the

capstans

and

flywheels

will

stay

in

place

during

the

dismantling.

2.

Unhook

the

connecting

spring

from

the

mounting

plate.

Be

sure

to

note

which

notch

the

spring

is

fastened

to,

so

that

you

will

be

able

to

replace

it

correctly.

3.

|

Unhook

the

drive

belt

from

the

pulley.

4.

Remove

the

circlip

on

the

front

side

of

the

cassette

compartment

(see

fig.).

5.

Unhook

the

locking

lever

from

the

cassette

compartment.

The

cassette

compartment

can

now

swing

upwards.

6.

Unscrew

the

two

screws

(B)

holding

the

guide

brackets

for

the

mounting

plate.

7.

Unhook

the

two

guide

brackets

and

pull

them

out

through

the

holes

(C).

8.

Remove

the

mounting

plate

carefully.

1

12.

13.

14.

Unscrew

the

three

screws

(D)

holding

the

flywheel

mounting

plate

and

—

lift

out

the

flywheel

mounting

plate

with

capstans

and

flywheels.

Remove

the

old

drive

belt.

Place

the

new

drive

belt

around

the

flywheels

and

hook

it

around

the

cassette

guides

(see

fig.)

TAKE

CARE

NOT

TO

GET

OIL

OR

GREASE

ON

THE

DRIVE

BELT.

Replace

the

flywheel

mounting

plate

and

hook

the

drive

belt

around

the

pulley.

NOTE!

The

drive

belt

should

pass

under

the

counter

drive

belt.

Replace

the

mounting

plate

and

check

that

it

runs

freely

back

and

forth.

Add

a

little

grease

on

the

ball

bearings

if

required.

se

Mobilplex

grease

No.

47

or

equivalent.

Replace

all

other

parts.

Remove

the

sellotape

from

the

capstans

and

CLEAN

THE

CAP-

STANS

THOROUGHLY.

Insert

a

cassette

and

check

that

the

tape

does

not

stick

to

the

capstans.

3.4

CASSETTE

ARM

The

cassette

arm

can

be

adjusted

by

bending

the

end

which

normally

rests

against

the

cassette

(see

figure).

Insert

a

cassette,

close

the

cassette

compartment

and

check

the

following:

—

The

cassette

should

rest

against

the

cassette

guides.

—

Microswitch

MS

4

should

be

closed.

(If

neces-

sary,

MS

4

can

be

adjusted

by

bending

the

support

bracket

for

the

microswitch).

—

The

locking

lever

extending

from

the

cassette

compartment

and

down

through

a

slot

in

the

motor

support

plate

should

be

about

2

mm

from

the

right

end

of

this

slot

(see

figure).

NOTE!

If

the

cassette

arm

is

bent

too

much

to

the

right,

the

locking

lever

will

be

moved

so

far

to

the

left

that

it

will

not

lock

the

cassette

compartment

in

the

lower

position.

—

When

the

cassette

compartment

is

released,

the

cassette

arm

should

push

the

cassette

half-way

out

of

the

compartment.

3.5

PINCH

ROLLER

SOLENOID

1.

Set

the

deck

to

play.

2.

Check

that

the

connecting

spring

is

stretched

approximately

0.5

-

0.7

mm.

The

figure

shows

how

this

check

is

made.

(Lhe

microswitches

are

not

shown

in

the

figure).

3.

If

necessary,

adjust

by

turning

the

nylon

screw

in

the

armature

of

the

solenoid.

To

reach

this

screw:

Switch

off

the

power,

lift

the

inner

top

plate

(with

the

indicators)

to

vertical

position.

Adjust

by

angling

the

screwdriver

towards

the

armature

from

the

left.

4.

Check

with

a

gauge

that

the

force

needed

to

lift

the

pinch

rollers

away

from

the

capstans

is

1000

-

1200

grams.

5.

If

necessary,

this

force

can

be

adjusted

by

moving

the

connecting

spring

to

another

notch.

If

the

spring

is

moved,

the

spring

tension

must

be

checked

again

as

explained

in

2.

10

Position

of

locking

lever

(cassette

in

compartment)

Spring

tension

(cassette

deck

in

PLAY)

Pinch

roller

pressure

3.6

PAUSE

CONTROL

When

the

PAUSE

button

is

depressed,

the

gap

between

pinch

rollers

and

capstans

can

be

adjusted

with

a

screw

marked

*PAUSE

ADJUST”,

which

can

be

reached

by

removing

the

right

side

wall.

Insert

a

cassette

and

set

the

deck

to

PLAY.

Depress

the

PAUSE

button

a

few

times,

and

check

the

following:

—

The

PAUSE

lever

should

move

freely,

without

touching

the

motor

support

plate

or

the

bracket

of

the

PAUSE

switch.

(If

required,

this

bracket

can

be

bent

a

little

with

a

screwdriver.)

—

When

the

PAUSE

button

is

depressed,

the

tape

should

stop,

and

the

pinch

rollers

should

be

lifted

away

from

the

capstans.

The

gap

must

be

wide

enough

that

neither

of

the

pinch

rollers

touch

the

capstans

under

any

circumstance.

If

required,

adjust

with

the

PAUSE

ADJUST

screw.

—

At

the

same

time,

the

gap

must

be

so

narrow

that

the

pinch

roller

solenoid

will

pull

the

pinch

rollers

in

again

when

the

PAUSE

button

is

re-

leased,

both

during

PLAY

and

RECORD.

IMPORTANT!

With

the

deck

in

PLAY,

release

the

PAUSE

button

and

check

that

the

PAUSE

lever

can

be

moved

a

little

up

and

down

(as

indicated

with

an

arrow

in

the

figure).

If

the

lever

cannot

be

moved,

the

reason

is

probably

that

the

PAUSE

ADJUST

screw

butts

against

the

lever,

and

the

force

of

the

pinch

roller

solenoid

is

transferred

to

the

lever.

The

pressure

of

the

pinch

rollers

is

then

correspondingly

reduced.

3.7

ADJUSTING

THE

POSITION

OF

A

REEL

MOTOR

Insert

a

high

quality

cassette

and

close

the

cassette

compartment.

Check

that

the

tape

spindle

on

the

motor

is

exactly

in

the

center

of

the

correspond-

ing

hub

on

the

cassette.

Try

the

recorder

in

play,

wind

and

rewind.

Check

that

the

hub

runs

easily

and

does

not

wobble.

If

necessary,

adjust

by

loosening

the

two

screws

holding

the

reel

motor.

This

will

be

easier

if

you

remove

the

circlip

on

the

left

side

of

the

cassette

compartment

and

swing

the

cassette

compartment

upwards

(see

page

8,

step

4).

The

ree]

motor

can

now

be

moved

slightly.

3.8.

SALVAGING

TANGLED

TAPE

Occasionally

the

tape

will

wind

itself

around

the

last

of

the

two

capstans.

To

salvage

the

tape

proceed

as

follows:

1.

Remove

the

bottom

plate

of

the

deck.

2.

Turn

the

flywheel

of

the

entangled

capstan

slowly

against

its

normal

rotation.

Use

your

finger

to

turn

the

flywheel.

3.

When

the

tape

has

been

untangled

from

the

capstan,

wind

it

manually

onto

the

hubs

of

the

cassette.

Turning

the

flywheel

in

order

to

salvage

tangled

tape

11

4.

MOTOR

AND

SOLENOID

CIRCUITS

4.1

ASHORT

EXPLANATION

OF

THE

SOLENOID

OPERATING

CIRCUIT

(0305,

0306)

Operation

of

the

pinch

roller

(start)

solenoid

should

be

slightly

delayed,

to

give

the

reel

motors

time

to

remove

any

slack

in

the

tape,

before

the

pinch

rollers

are

pulled

in.

When

both

PLAY

and

RECORD

buttons

are

re-

leased,

C316

has

no

voltage

and

Q307

(PNP)

is

cut-

off.

Q306

(NPN)

has

a

base

voltage

of

0

V

and

is

also

cut-off.

When

the

PLAY

or

RECORD

button

is

depressed

the

following

sequence

is

started:

1.

12

START

/

STOP

CIR

cu

DO

AR

2068

13.5

V

is

connected

to

the

+side

of

C316.

The

voltage

drop

over

R326

gives

Q307

an

emitter

voltage

of

about

11

V.

The

transistor

requires

a

base

voltage

which

is

0.7

V

more

negative

than

the

emitter

to

start

conducting.

The

transistor

|

will

therefore

still

be

in

cut-off

state.

Jcsirare

te

Solenoid

operating

circuit

.

C316

is

charged

through

R328/R333.

The

posi-

tive

voltage

at

point

A

is

connected

via

C315

to

the

base

of

Q307.

This

voltage

is

gradually

reduced

as

C316

is

charged.

.

After

a

little

while,

the

voltage

at

point

A

has

been

reduced

so

much

that

the

base

of

Q307

drops

lower

than

10.3

V,

and

the

transistor

starts

conducting.

.

When

Q307

starts

conducting,

the

collector

voltage

increases,

driving

Q306

into

conducting

state.

Point

B

is

connected

to

ground,

current

passes

through

the

activate”

coil

(Ly)

of

the

start

solenoid

and

the

pinch

rollers

operate.

.

When

Q306

is

conducting,

the

current

to

C316

passes

through

R332

and

Q306,

C316

will

there-

fore

be

fully

charged

in

a

very

short

time.

.

When

C316

is

fully

charged,

there

will

be

no

voltage

at

point

A,

and

C315

is

charged

through

R325,

The

current

through

R325

will

keep

Q307

in

conducting

state.

.

After

a

little

while

the

current

to

C315

has

been

reduced

so

much

that

Q307

goes

cut-off.

Q306

also

goes

cut-off,

stopping

the

current

through

the

activate”

coil.

START

Ty

SOLENDIC

4.2

A

SHORT

EXPLANATION

OF

THE

MOTOR

CONTROL

CIRCUITS

When

the

reel

motors

revolve,

they

generate

pulses.

These

pulses

are

used

to

control

the

motor

power

supply.

When

both

motors

are

stationary,

no

pulses

are

fed

to

the

motor

signal

amplifier.

Q504

of

the

Schmitt-

trigger

is

cut-off,

and

Q505

is

conducting.

Q507

is

also

conducting,

and

the

motor

power

supply

is

connected

to

ground.

Therefore,

no

voltage

is

fed

to

the

motors.

When

the

REWIND,

WIND,

PLAY

or

RECORD

button

is

depressed,

one

of

the

capacitors

C317,

C320

or

C321

will

give

a

trigger

pulse

to

the

Schmitt-trigger.

Q504

starts

conducting

and

Q505

goes

cut-off.

Q507

also

goes

cut-off,

and

the

motor

power

supply

feeds

a

voltage

to

the

motors

(via

microswitches

and

operating

switches).

‘The

motors

start

revolving,

feeding

pulses

to

the

motor

signal

amplifier.

The

output

from

this

amplifier

will

keep

Q504

in

conducting

state.

During

wind

or

rewind

the

supply

motor

works

as

a

generator,

feeding

a

negative

voltage

to

transistor

Q506,

which

regulates

the

motor

power

supply.

The

voltage

from

the

power

supply

is

therefore

dependent

on

the

speed

of

the

supply

reel.

When

the

tape

stops

(for

instance

at

the

end

of

the

tape)

the

input

to

the

motor

signal

amplifier

drops

to

zero,

and

the

Schmitt-trigger

reverts

to

unope-

rated

state

after

a

short

delay

(determined

by

C508/R512).

Q507

starts

conducting

and

the

voltage

from

the

motor

power

supply

drops

to

zero.

4.3

CONTROL

OF

MOTOR

VOLTAGES

Remove

the

bottom

plate,

insert

a

cassette

in

the

deck

and

check

that

the

voltages

across

the

motors

are

as

specified

below:

OV

0.7V~0.8V

|

0.7V—-08V

Drops

to

0

Drops

to

0

after

a

short

after

a

short

while

10V~3.5V

Drops

to

0a

little

while

after

the

end

stop

is

reached

10V—3.5V

Drops

to

0a

little

while

after

the

end

stop

is

reached

Block

diagram

of

motor

control

circuits

13

5.

ELECTRICAL

ADJUSTMENTS

GENERAL

.

NECESSARY

EQUIPMENT

—

”0

dB”

level

is

defined

as

775

mV.

Thus

—5

dB

—

2high

impedance

voltmeters

(do

NOT

use

equals

450

mV

and

—35

dB

equals

14

mV.

universal

meters).

—

Frequency

counter.

; .

;

—

Audio

generator.

—

Make

the

adjustments

in

the

order

in

which

they

are

listed

here.

Many

of

the

adjustments

require

that

have

already

been

—

Wow

meter

(required

for

wow

test

only).

correctly

made.

It

is

especially

important

that

adjustment

for

CrOg

tape

be

made

before

adjust-

ment

for

HL

tape.

—

Tandberg

test

tapes

No.

21

(1,000

Hz

speed

test),

No.

22

(3,150

Hz

wow

test),

No.

23

(6,300

Hz

azimuth

test)

and

No.

24

(1,000

Hz

playback

™

level).

—

TDK

C60

CHROM

or

equivalent

chromium

dioxide

cassette.

—

Distortion

meter.

—

Hum/noise

meter

(required

for

signal/noise

test).

—

Clean

and

degauss

the

tape

path

before

and

after

the

adjustments.

It

is

assumed

that

the

tape

path

has

already

been

correctly

adjusted

as

described

on

pages

5,

6

and

7.

—

Maxell

C60

UD

or

equivalent

HL

cassette.

Location

of

test

points

and

adjustable

components:

see

page

17

Azimuth

Adjust

to

best

signal.

Difference

screw

on

|compromise

between

the

tracks:

|

head

<

4¢dB

1775

mV

R317

(left

ch.)

R417

(right

ch.

Playback

c

+

1%

(990

—

1010)

Playback

S

0.2%

Measure

at

end

of

{DIN

45,507

tape.

Measure

both

peak

weighted)

in

vertical

and

hori-

45.507)

zontal

position

CrO2

Frequency

|Connect

80

-

100

kHz

Connection

is

made

Recording

counter

inductively

with

a

coil

or

a

few

to

erase

turns

of

ordinary

head

(see

wire.

Instead

of

a

comments)

frequency

counter

a

long-wave

receiver

(

tuned

to

3rd

har-

monic)

can

be

used

|

CrO2

Voltmeter

[Across

[28

—

32

V

Recording

lerase

head

CrO2

Voltmeters

[OUTPUT

|<

5

mv

lps

INPUT

sockets

open

|

Recording

|

sockets

=

CrO2

Voltmeters

[R319

(left)

[Minimum

L301

{left

ch.)

|

The

filters

prevent

Recording

R419

(right)|reading

L401

(right

ch.)

|

the

record

amplifiers

to

ground

\{2—4

V}

from

short-circuiting

the

bias

voltage

to

ground

130!

-===4

TO

REC

/PLAY

HEAD

TO

OUTPUT

OF

REC

AMP

cH

RTS

Voltmeters

|

R801

(left

ch.)

CrOz

|

Voltmeters

|Set

the

cassette

deck

to

CrO2

recording

and

adjust

R901

{right

ch.)

|€801

(left

ch.)

and

C901

(right

ch.)

to

readings

of

see

“location’’

drawing

OUTPUT

sockets

approximately

6—8

mV.

(Measure

between

ground

and

the

side

of

the

resistor

which

is

connected

to

the

head.)

Set

the

cassette

deck

to

CrO2

recording.

R1

and

R2

to

mid-position.

Connect

an

audio

generator

to

the

INPUT

sockets.

Adjust

the

jgenerator

to

400

Hz,

-5

dB

(=

450

mV

on

the

voltmeters).

(—5

dB

is

used

instead

of

0

dB

in

order

to

avoid

inaccurate

results

caused

by

varying

tape

characteristics.

y

varying

tap

)

Bakes

output

Rewind

and

play

back.

The

voltmeters

should

now

read

—5

dB

(=450

mV)

+

0.5

dB.

If

outside

the

tolerance,

make

a

new

recording

while

adjusting

R105

(left

ch.)

and

R205

(right

ch.)

as

required.

Then

play

back

and

check

once

more.

Voltmeters

Distortion

meter

Voltmeters

CrQ2

|

Indicators

Mian

aa

Voltmeters

HL

Voitmeters

|

i

H

Distortion

meter

;

HL

Voltmeters.

Voltmeters

Hum/noise

meter

(according

to

DIN

45.405)

OUTPUT

sockets

OUTPUT

sockets

OUTPUT

sockets

OUTPUT

sockets

OUTPUT

sockets

OUTPUT

sockets

OUTPUT

sockets

Set

the

cassette

deck

to

CrOg

recording.

Adjust

the

generator

to

—35

dB

{=

14

mV

on

the

voltmeters)

and

record

a

400

Hz

and

a

10,000

Hz

signal

at

this

level.

Rewind

and

play

back.

Use

the

400

Hz

signal

as

a

reference

and

check

on

both

channels

that

the

10,000

Hz

signal

is

within

the

following

tolerance:

-0

dB

to

+5

dB.

If

outside

the

tolerance

adjust

C801

and

C901

(bias).

Then

make

a

new

recording,

play

back

and

check

once

more.

Set

the

cassette

deck

to

CrOg

recording.

Generator

to

1000

Hz,

0

dB

(=775

mV

on

the

voltmeters).

Rewind

and

play

back.

Check

that

the

distortion

is

S

5%

(3rd.

harmonic

distortion

according

to

DIN

45,405).

If

outside

the

tolerance

adjust

C801

and

C901

(bias).

Make

a

new

Set

the

cassette

deck

to

CrO2?

DOLBY

(!)

recording.

Adjust

the

generator

to

—35

dB

and

record

the

following

frequencies:

400

Hz,

55

Hz,

1000

Hz,

4000

Hz,

10,000

Hz,

12,500

Hz.

Rewind

and

play

back.

Use

the

400

Hz

signal

as

a

referance,

and

check

that

the

other

signals

are

within

the

following

tolerances:

55

Hz:

~3

dB

to

+2

dB

10,000

Hz:

OdBto+

5B

1000

Hz:

~2

dB

to

+2

dB

12,500

Hz:

—2

dB

to

+

5

4B

4000

Hz:

—2

dB

to

+4

dB

If

outside

the

tolerances

try

changing

the

values

of

Cb01/C502

(left

ch.)

and

€601/C602

(right

ch.).

Increased

values

give

higher

treble

response.

Record

a

400

Hz,

0

dB

signal

and

adjust

R115

(left

ch.)

and

R215

(right

ch.)

to

0

dB

deflection

on

both

indicators.

Same

as

in

step

9.2,

except

that

the

CrOg

button

is

released.

If

outside

the

tolerance

adjust

R104

(left

ch.)

and

R204

(right

ch.).

DO

NOT

TOUCH

R105

OR

R205.

NOTE!

Adjustment

of

R104

and

R204

will

not

affect

the

readings

on

the

indicators

of

the

cassette

deck.

Same

as

in

step

9.3,

except

that

the

CrO9

button

is

released,

If

outside

the

tolerance

adjust

R807.

DO

NOT

TOUCH

C801

OR

C901.

Same

as

in

step

9.4,

except

that

the

CrOg

button

is

released.

If

outside

the

tolerance

adjust

R807.

Then

repeat

11.2.

DO

NOT

TOUCH

C801

OR

C901.

Same

as

in

step

9.5,

except

that

the

CrO9

button

is

released.

Tolerances:

55

Hz:

—3

dB

to

+2

dB

10,000

Hz:

—2

dB

to

+5

dB

1000

Hz:

—-2

dB

to

+2

dB

12,500

Hz:

—3

dB

to

+4

dB

4000

Hz:

-2

dB

to

+4

dB

If

outside

the

tolerances

try

changing

the

values

of

C503/C510

(left

ch.)

and

C603/C604

(right

ch.).

Increased

values

give

higher

treble

response.

Record

a

400

Hz,

0

dB

signal.

Rewind

and

erase.

Then

rewind

once

more

and

play

back

the

erased

piece.

The

voltmeters

should

read

<—

62

cB.

The

signal/noise

ratios

at

5

%

distortion

should

be

at

least

as

good

as

specified

in

the

table

below:

NORMAL

DOLBY

Signal/tape

noise:

HL

CrO2

HL

CrO2

DIN

45.511

(Gerauschspannung)

46

dB

49

dB

55dB

58

dB

DIN

45.511

(Fremdspannung)

46dB

48dB

50dB

50

dB

Oscillator

|

|]

Dolby

boards

104

@)

sot

503]

C603

“A208

=

|

Amplifier

2

board

fa)

i)

a

RNIB

R108

A205

A216

A31

'®

Mue

Amplifier

I

board

SRE

30m

BRO)

1

C80’

Ago

C901

AZIMUTH

1407

L301

=X

|

woo

Gl...

Location

of

test

points

and

adjustable

components

Oscillator

|

|]

Dolby

boards

104

@)

sot

503]

C603

“A208

=

|

Amplifier

2

board

fa)

i)

a

RNIB

R108

A205

A216

A31

'®

Mue

Amplifier

I

board

SRE

30m

BRO)

1

C80’

Ago

C901

AZIMUTH

1407

L301

=X

|

woo

Gl...

Location

of

test

points

and

adjustable

components

Dolby

boards

roa

©

cor

©

conn

R215,

Amplifier

2

board

g

is)

A

ATS

R105

R205

cits

@

aL

Amplifier

1

beard

_

Location

of

test

points

and

adjustable

components

Dolby

board

Oscillator

board

Amplifier

1

board

=}

=

>

au

09:

¥,

be

Ae

H*

g

a

Ss

@)

|

@—Toicut

car

a5,

;

e050

©

eer

am

il!

-

fa

>

Sho

~

Ba

ara

a

3g

t

og

WATTS

a

om

&

8

is)

es)

N

&

8

&

3

Q

=

x

ee

BOARO

NO

60209

|

I

|

[

|

[

|

!

|

Vas5

|

V3

MIC.

/

LINE

AMP

RIGHT

AMPLIFIER

I

Ov

All

voltages

are

measured

with

VTV.M

with

input

Impedance

min

10M

ohms

Ail

DC

voltages

measured

without

signal

Ged)

Denotes

signal

volieges

(1000Hz)

TmV

Denotes

OC

voltages

{10V}

Denotes

voltages

in

operated

mode

RECORD

LEVEL

LEFT

i

362

42

320

REWIND

7

z

a

sToP

WIND

i

-—4

ma

|

ke

Remo

paberviu

sins

¢

ay

Se

ie

1}...

START/

STOP

CIRCUIT

CAIs

CAG

0p

1000p

RECORD

LEVEL

RIGHT

Le

Lett

channel

{Track

|

or

tale

3

4701

L702

&

=--4

=~

13.5V

>

“

EEE

MS3

NS

MS&

REC

SUDE

CASSETTE

680

p

4)

Re

Right

channel

[Track

2

oF

3)

—}

=

Connector

O10)

=

Connection

terminel

Signal

path

—

RECORDING

Signal

path

—

PLAYBACK

~

:.

9°

]

J

MS2

MUTING

123

104

{750}

Ra

+4

\j

ae

f

:

r|

U3,

a

Ls

ea

aS,

337

Green

Z

Blue

304!

+234

Start

—————

8

fis

SOLENQIC

as!

JPLAYE,

Bb

(Se

MOTOR

SIGNAL

AMPLIFIER

ee

SE

ES

BC

147

BC

1498

Be

169

---p>---

TRANSIS

E(D)

Ge

ctG)

2N5087

MPS

6518

(2N5458)

TORS SEEN

FROM

UNDERNEATH

TANDBERG TCD 310 User manual

Popular Cassette Player manuals by other brands