Telefunken M 204 e Operating and installation instructions

TELEFUNKEN

Service

Information

Technical

Data

Power

Supply:

Power

Consumption:

Tape

Speed:

Track

Arrangement:

Spool

Size:

Playing

Time:

Rewind

Time:

Magnetic

Heads:

Bias

Frequency:

Erase

Frequency:

Equalisation:

Semiconductors

Fitted:

Transistors:

Rectifiers:

Diodes:

Inputs:

Outputs:

Output

Stages:

Frequency

Range:

Dynamic

Range:

Wow

and

Flutter

(Pitch

Fluctuations):

110,

127,

220

and

240

Volts,

50

Hz

AC,

switch-selectable,

may

be

switched

to

60

Hz

approx.

60

Watts

9.5cm/s

and

19cm/s,

switch-selectable

4-track

standard

according

to

DIN

45511

for

monaural

and

stereophonic

operation

up

to

18

cmdiam.,

according

to

DIN

45514

4x

120

min

at

9.5

cm/s

with

720

m

double-play

tape

and

monaural

operation;

playing

time

halved

at

19

cm/s

about

5.5

min

for

720

m

double-play

tape

1

record/playback

head,

G415,

1

erase

head,

L315

85

kHz

85

kHz

according

to

DIN

45513

2xAC

150,

8x

AC

122,

1x

AC

124

1x

AC

175,

2x

AC

123,

4x

AD

152P

AEG

B

30

C

1200/650

K6

2x

OA

150

Radio:

2x0.15mV

across2

kQ

Pickup

(Phono):

2x

150

mV

across

2.2

MQ

Tape:

2x

150

mV

across

2.2

MQ

2

x

Microphone:

2x0.15mV

across2

kQ

new

input

circuit

Radio:

2x0.15mV

across5

kQ

Pickup

(Phono):

2x70

mV

across

2.2

MQ

Tape:

2x70

mV

across

2.2

MQ

2

x

Microphone:

2x0.15mV

across5

kQ

Radio:

2x1.5

V

across8

kQ

Earphones,

mono:

0.5

V

across5

kQ

load

Earphones,

stereo:

2x0.5

V

across5

kQ

load

Loudspeakers:

2x10Q

(>

4Q)

Push-Pull,

2

x

6

Watts

music

power

40

Hz

to

17

kHz

for

19

cm/s

40

Hz

to

14

kHz

for

9.5cm/s

47dB

for

19cm/s

45

dB

for

9.5

cm/s

acoustic

assess-

ment,

measured

according

to

DIN

45507

+0.2%

for

19

cm/s

+0.3%

for

9.5cm/s

Harmonic

Distortion

Factor:

<S5%

Loudspeakers:

built-in,

2

loudspeakers

100

x

180

mm,

oval,

may

be

switched

off

with

switch-jack

Fuses:

2x0.4A

medium

delayed

2x

0.315

A

medium

delayed

Pilot

Lamp:

subminiature

lamp

24

V

/

0.08

A,

as

on/off

indicator

Dimensions:

standing

upright,

width

x

height

x

depth

475

x

365

x

225

mm

with

lid

x

220

mm

without

Weight:

approx.

14kg

Special

Features:

May

be

operated

in

horizontal

or

vertical

orientation.

Completely

independent

controls

for

the

two

channels.

Mains

Selection

The

Model

M

204

tape

recorder

may

be

set

for

alternative

Operation

on

4

mains

input

voltages

and

two

mains

frequencies.

The

voltage

selector

switch

and

the

two

changeover

lugs

for

the

50/60

Hz

conversion

are

accessible

after

taking

off

the

rear

panel

of

the

unit

(3

cross-slot

screws).

For

the

50/60

Hz

conversion

it

is

also

necessary,

after

taking

off

the

control

knobs

and

the

front

panel,

to

place

the

motor

belt

into

the

appropriate

groove

of

the

motor

pulley

(small

diameter

for

60

Hz,

large

diameter

for

50

Hz).

Maintenance

Cleaning

the

Cabinet

Components

To

clean

the

handle,

use

ordinary

commercial

cleaners

for

plastic.

The

choice

wood

casing

should

be

cleaned

with

ordinary

com-

mercial

polish

based

on

water

as

solvent.

An

anti-static

substance

or

device should

be

reapplied

from

time

to

time

to

the

plastic

components,

se

that

these

remain

dust

-repellent.

Cleaning

the

Tape

Drive

Components

Regularly

remove

deposits

of

tape

dust.

For

this

purpose,

pull

off

the

tape

heads

covering

hood,

and

with

a

linen

rag

moistened

with

isopropyl

alcohol,

clean

the

tape

guides,

the

drive

capstan,

the

rubber

pressure

roller

and

the

tape

contact

surfaces

of

the

heads.

Clean

the

perlon-silk

pressure

pad

on

the

racord/play-

back

head

with

a

small

dry

brush.

If

this

pad

possesses

hardened

regions,

it

must

be

replaced

(see

hum

suppression

flap,

replace-

ment

item).

Cleaning

the

Drive

From

time

to

time

as

well

as

after

any

repairs

to

the

drive

mechanism,

clean

all

drive

components,

the

rubber

brakes,

the

brake

surfaces

of

the

spool

plates,

as

well

as

the

capstan

and

the

rubber

pressure

roller.

For

this

purpose,

use

a

clean

linen

rag

moistened

with

isopropyl

alcohol.

(Methylated

spirit

is

less

suitable,

since

it

is

unable

to

dissolve

molykote

contaminations).

Oiling

and

Greasing

The

unit

is

fitted

with

self-lubricating

sintered

bearings

which

give

maintenance-free

operating

times

of

several

thousand

hours.

If

a

bearing

should

happen

to

run

with

much

friction,

it

is

advisable

to

replace

the

component

concerned.

Re-oiling

would

bring

about

the

danger

of

contaminating

the

drive

with

oil

spray.

The

sliders

of

the

actuator

rods

and

the

bearing

brackets

should

be

lubricated

at

the

bearing

points

with

Siemens

uniselector

grease,

and

with

Molykote

Paste

G

Rapid

at

all

places

where

metallic

components

slide

against

each

other

(e.g.

the

press-

button

assembly).

The

prismatic

bearing

for

the

drive

capstan

on

the

head

carrier

plate

is

also

lubricated

with

molykote.

Re-greasing

is

necessary

only

.after

replacing

components,

or

when

a

particular

component

does

not

run

freely.

Molykote

must

always

be

applied

as

an

extremely

thin

film.

Lubricating

grease

or

molykote

must

not

be

used

for

sintered

bearings.

Demagnetisation

(Degaussing)

Tape

drive

components

and

magnetic

heads

may

become

magne-

tised

when

approached

with

magnetic

tools

or

cables

carrying

direct

current.

This

produces

a

permanent

background

noise

on

the

tapes

during

operation.

To

prevent

this

defect,

we

recommend

careful

and

thorough

degaussing

of

all

metallic

components

which

come

into

contact

with

the

tape,

after

every

completed

repair

job

(degaussing

choke

for

220

V

AC,

Order

No.

60.89.108).

All

adjustment

values

and

direction

specifications

refer

to

vertical

operation

of

the

unit.

Operating

Instructions

Track

Selection:

The

function

selector

switch

@

is

blocked

in

the

“Recording”

operating

mode,

so that

track

selec-

tion

must

be

made

in

the

“Stop”

or

“Playback“

settings.

Stereo:

Turn

switch

@

to

position

“Stereo".

Mono:

Turn

switch

@

to

position

“1“

or

“2".

Parallel:

|

Turn

switch

©

to

position

“P“;

only

for

parallel

playback

of

both

tracks.

Multi-Play:

Turn

switch

@

to

position

“2/1“

or

“1/2",

according

as

to

whether

trans-

cription

is

to

be

made

from

track

2

to

track

1,

or

from

track

1

to

track

2

respectively.

The

drive

level

of

the

new

recording

is

always

to

be

ad-

justed

with

the

control

@

and

the

drive

level

of

the

transcription

recor-

ding

is

always

to

be

adjusted

with

the

control

®.

Recording.

Turn

the

function

selector

switch

@

to

the

desired

setting

and

press

the

recording

button

@.

Then

ad-

just

the

drive

level

for

monaural

recordings

with

the

control

@,

and

for

stereophonic

recordings

with

control

@

for

the

left

channel

and

control

©

for

the

right

channel.

The

meter

pointers

should

deflect

up

to

the

start

of

the red

sectors

on

volume

peaks,

excursians

into

the

red

sectors

being

at

most

very

brief.

After

correct

drive

adjustment,

hold

the

recor-

ding

button

@

depressed

and

press

the

drive

button

@)

additionally

thereto.

The

stop

button

@)

must

be

actuated

prior

to

any

change

of

the

operating

mode.

Manual

Controls

and

Connecting

Jacks

@

Connecting

jack

for

radio

receiver

(mono/stereo

or

VHF

stereo

tuner)

or

separate

Hi-Fi

stereo

amplifier

@

Connecting

jack

for

record

player

(mono/stereo),

also

for

Hi-Fi

record

player

with

built-in

equaliser-preamplifier.

@®

Connecting

jack

for

monaural

earphones

for

“silent“

moni-

toring

during

monaural

recordings.

@®

Connecting

jack

for

stereophonic

earphones

for

“silent“

moni-

toring

during

stereophonic

recordings.

®

Connecting

jack

for

separate

Hi-Fi

loudspeaker

box

(left

channel);

or

jack

for

Hi-Fi

earphones.

©

Connecting

jack

for

separate

Hi-Fi

loudspeaker

box

(right

channel);

or

jack

for

Hi-Fi

earphones.

@

Insertion

slot

for

tape.

Rapid

stop

button,

can

be

latched.

@®

3-digit

counter

mechanism,

counts

forwards

and

backwards,

resettable

to

zero

with

pressbutton.

ELE

)

@

68

©G©@6©000

@®

®@

@@0©8D

©

®©

®

Fig.1

Connecting

Jacks

and

Manual

Controls

left

indication

only

on

this

@

VU-meter

for

checking

the

recording

drive

(for

stereo

=

channel;

for

mono

and

transcription

=

meter);

at

the

same

time

serves

as

illuminated

on/off

indicator.

@

VU-meter

for

checking

the

recording

drive

(for

stereo

=

right

channel;

for

mono

transcription

no

indication

on

this

meter);

at

the

same

time

serves

as

illuminated

on/off

indicator.

@

6-position

function

selector

switch

for

stereo/mono/transcrip-

tion

and

prallel

playback.

@®

Recording

drive

level

control

(for

stereo

=

right

channel;

for

transcriptions

=

transcription

level

control).

@

Recording

drive

level

control

(for

stereo

=

left

channel;

for

mono

=

drive

level

adjustment

only

with

this

control;

for

transcriptions

=

mixer

control).

®

Tone

control,

for

stereo

for

the

right

channel,

for

mono

for

the

right

power

amplifier.

®

Tone

control,

for

stereo

for

the

left

channel,

for

mono

for

the

left

power

amplifier.

@

Mains

switch,

on/off.

Input

selector

switch

Microphone

—

Radio/Phono;

for

stereo-

phonic

recordings

for

the

right

channel,

for

monaural

recor-

dings

setting

of

this

switch

without

significance.

®

Connecting

jack

for

stereophonic

microphone,

right

channel

(for

microphones

plugged-in

separately).

Without

significance

for

monaural

recordings.

@

Connecting

jack

for

stereophonic

microphone,

left

channel

(for

microphones

plugged-in

separately),

or

for

stereophonic

microphone

with

only

one

plug

(left

and

right

channel),

or

for

microphone

for

monaural

recordings.

@

Input

selector

switch

Microphone

—

Radio/Phono;

for

stereo-

phonic

recordings

for

the

left

channel,

for

monaural

recordings

this

switch

alone

is

effective.

@

Volume

control

for

playback

via

power

amplifier

(for

stereo

=

right

channel,

for

mono

=

right

power

amplifier).

®

Volume

control

for

playback

via

power

amplifier

(for

stereo

=

left

channel,

for

mono

=

left

power

amplifier).

@

Recording

button

(blocks

the

function

selector

switch

@).

®

Button

for

fast

forward

drive.

@

Tape

drive

button;

press

alone

for

playback;

press

in

addition

to

button

@

for

recording.

@

Button

for

fast

rewind.

STOP

button

(actuation

of

this

button

causes

other

buttons

to

jump

back

to

resting

state).

:

@®

Guide

rail

for

splicing

tapes.

@

Rubber

caps

for

retaining

the

spools

during

vertical

operation

of

the

unit.

A

Tape

speed

selector

19

cm/s

—

9.5

cm/s

(operate

only

when

the

unit

is

switched

on).

To

Open

the

Unit

Before

opening

the

unit,

withdraw

the

mains

plug

from

the

power

socket.

To

take

off

the

floor

Screw

out

the

three

cross-slot

screws

of

the

metallic

floorplate

and

the

two

screws

of

the

coverplate.

Take

off

the

floorplate

and

pull

the

mains

plug

through

the

opening.

ee

To

fold

out the

amplifier

board

Screw

out

the

four

retaining

screws

of

the

amplifier

board

(at

the

yellow

triangular

spacers).

Fold

out

the

amplifier

board.

To

take

out

the

output

stage

assembly

Screw

out

the

three

retaining

screws

of

the

printed

circuit

board

(in

the

black

triangular

spacers)

and

the

two

fixing

screws

of

the

cooling

fin.

Take

out

the

assembly.

To

take

off

the

head

covering

Using

both

hands,

press

downwards

the

sidewings

of

the

head

covering

close

above

the

coverplate,

and

pull

off

the

head

covering

forwards.

To

take

off

the

coverplate

Pull

off

the

six

control

knobs

and

the

knob

of

the

function

selector

switch

forwards,

and

pull

off

the

rectangular

knob

of

the

tape

speed

selector

in

the

direction

of

the

changeover

lever.

The

coverplate

can

then

be

taken

off

after

releasing

the

six

cross-slot

screws.

Six-Jack

Bracket

Screw

out

four

screws

in

the

chassis

from

the

front.

Fold

out

the

jacks

bracket

(it

is

not

necessary

to

take

off

the

mask).

Feed

Plate

Assembly

(on

left,

looking

onto

chassis)

The

components

are

listed

in

order,

commencing

at

the

bottom

as

seen

looking

onto

the

chassis:

—

Slider

for

elevation

adjustment

of

the

feed

plate

Profile

block

to

compensate

the

inclined

plane

of

the

slider

Plastic

washer

Lockwasher,

bronze

washer

and

star

spring

Supporting

plate

Lockwasher,

bronze

washer

and

star

spring

Brake

plate

with

felt

lining

Slip

plate

with

felt

lining

and

injected

bushing

with

bearing

Plastic

washer,

bronze

washer

and

tension

ring

Engagement

plate

Switch

and

Jack

Bracket

Screw

out

two

screws

from

the

rear

side

of

the

chassis,

release

the

anchorage

of

the

mains

cable,

pull

out

the

jacks

bracket

through

a

small

distance

and

turn

through

180°.

The

wiring

is

then

accessible.

Construction

and

Functional

Principles

The

complete

mechanism

of

the

magnetophon

204

is

built

on

a

sheet

metal

chassis

which

is

screwed

to

the

wooden

cabinet

frame.

Engagement

Plates

The

engagement

plates

engage

with

their

three

latching

pegs

into

the

bayonet

slots

of

the

slip

plates.

They

should

be

engaged

by

turning

towards

the

magnetic

heads.

To

disengage

them,

turn

in

the

other

direction,

but

not

too

far

since

otherwise

the

plates

latch

again.

To

latch

or

unlatch

the

plates,

hold

the

slip

plate

and

engage

or

release

the

engagement

plate

with

the

help

of

a

small

tape

reel.

The

tension

ring

below

the

engagement

plate

should

be

mounted

with

a

play

of

0.2

to

0.3

mm

with

respect

to

the

slip

plate.

Take-Up

Plate

Assembly

(on

right,

loocking

onto

chassis)

The

components

are

listed

in

order,

commencing

at

the

bottom

as

seen

looking

onto

the

chassis:

—

Slider

for

elevation

adjustment

of

the

take-up

plate

Profile

block

to

compensate

the

inclined

plane

of

the

slider

Plastic

washer

Lockwasher,

bronze

washer

and

three

star

springs

Supporting

plate

Lockwasher,

bronze

washer

and

one

star

spring

Brake

plate with

felt

lining

Slip

plate

with

felt

lining

and

injected

bushing

with

bearing

Plastic

washer,

bronze

washer

and

tension

ring

Engagement

plate

Fig.

2

Exploded

drawing

of

feed

plate

(left)

Fig.

3

Exploded

drawing

of

the

take-up

plate

(right)

ay

Feed

Plate,

left

Functional

Principles

of

the

Drive

Mechanism

The

unit

employs

a

round

profile

belt

drive.

The

symmetrical

shaded

pole

motor

drives

the

motor

belt,

which

in

turn

drives

two

intermediate

wheels

and

a

switching

wheel.

The

flywheel

disc

is

driven

from

this

switching

wheel,

via

the

drive

belt.

For

tape

drive

speed

changeover,

a

switching

rocker

throws

the

drive

belt

into

the

other

groove

on

the

switching

wheel

and

on

the

flywheel

disc.

~

Belt

Interrnediate

Wheel

Motor

Switching

Wheel

Tape

Drive

Belt

Flywheel

Disc

Fig.

4

Schematic

depiction

of

the

drive

mechanism

Important:

The

tape

drive

speed

may

be

switched

over

only

when

the

unit

is

switched

on.

Recording

—

Playback

When

the

tape

drive

button

is

pressed,

the

stop

brakes

release

the

feed

and

take-up

plates.

The

friction

wheel

is

pulled

in

between

the

flywheel

disc

and

the

supporting

plate

of

the

right

take-up

plate

assembly,

so

that

it

drives

the

right

brake

plate

via

a

slipping

clutch.

On

the

left

feed

plate

assembly,

an

auxiliary

brake

restrains

the

supporting

plate,

so

that

the

left

slipping

clutch

becomes

effec-

tive.

This

slipping

clutch

consists

of

the

supporting

plate

and

the

felt

ring

below

the

brake

plate.

Fast

Forward

Drive

When

the

fast

forward

drive

button

is

actuated,

the

stop

brakes

release

the

feed

and

take-up

plates.

The

auxiliary

brake

is

applied

to

the

left

supporting

plate.

The

rubber

coating

of

the

right

intermediate

wheel

is

pressed

against

and

thus

drives

the

right

brake

plate.

Excessive

starting

tension

is

not

exerted

on

the

tape,

because

this

is

prevented

by

the

tape

protection

coup-

ling

between

the

brake

plate

and

the

slip

plate.

Rewind

Drive

Once

again,

the

stop

brakes

release

the

feed

and

take-up

plates

when

the

rewind

button

is

actuated.

The

brake

releases

the

left

supporting

plate

and

the

rubber

coating

of

the

intermediate

wheel

is

pressed

against

and

drives

the

left

brake

plate.

The

tape

protection

coupling

on

the

left

plate

serves

the

same

function

as

the

one

on

the

right

plate.

The

tape

tension

is

established

with

the

felt

brake

below

the

right

take-up

plate.

Replacement

of

Componets

and

Mechanical

Adjustments

Replacing

the

Motor

Belt

After

unhooking

the

tension

spring,

fold

up

the

switching

rocker

towards

the

head

carrier

plate.

Twist

the

leaf

spring

from

its

normal

resting

position

towards

the

head

carrier

plate

and

place

the

motor

belt

into

the

upper

groove

of

the

switching

wheel,

over

the

intermediate

wheels

and

into

the

lower

groove

of

the

fan

wheel

(for

60

Hz

operation,

into

the

upper

groove

of

the fan

wheel).

Make

sure

that

the

motor

belt

runs

approximately

parallel

to

the

chassis

into

the

groove.

Replacing

the

Drive

Belt

Take

off

the

right

take-up

plate

and

screw

out

the

three

fixing

screws

1,

2

and

3

(Fig.

5)

of

the

head

carrier

plate.

Pull

off

the

head

carrrier

plate

upwards

from

the

drive

capstan

(the

plastic

prismatic

bearing

of

the

drive

capstan

remains

in

the

head

carrier

plate).

After

unhooking

the

tension

spring,

take

out

the

switching

rocker,

and

take

the

motor

belt

off

the

switching

wheel.

Insert

the

new

drive

belt,

first

of

all

into

the

upper

groove

of

the

flywheel

disc,

then

into

the

lower

groove

of

the

switching

wheel,

with

the

tape

drive

speed

selector

set

to

19

cm/s.

Reinsert

the

switching

rocker

and

make

sure

that

the

drive

belt

rests

in

the

two

cut-aways.

Remount

the

head

carrier

plate

onto

the

drive

capstan.

Check

that

the

plate

rests

securely

on

its

supports

and

that

the

lever

of

the

pressbutton

assembly

lies

in

front

of

the

slider

(F)

of

the

plate.

Tighten

the

screws

in

the

order

1,

2,

3

as

specified

on

Fig.

5.

If

the

dust

protection

ring

has

become

displaced,

press

it

down

only

to

such

an

extent

that

a

clearance

of

about

0.5mm

still

remains

with

respect

to

the

prismatic

bearing

in

‘the

head

carrier

plate.

The

dust

protection

ring

must

not

touch

the

upper

edge

of

the

rubber

roller.

If

the

dust

protection

ring

scrapes

against

the

bearing

or

against

the

rubber

rolier,

this

would

produce

pitch

fluctuations

and

rumble.

Clean

the

drive

capstan

with

isopropyl

alcohol.

Carry

out

a

functional

check.

Tape

Alignment

The

feed

and

take-up

plates,

the

tape

guides

and

the

record/play-

back

head

as

well

as

the

erase

head,

are

adjusted

to

a

uniform

height

in

the

factory.

As

a

rule,

readjustment

is

necessary

only

after

components

have

been

replaced.

Feed

and

Take-Up

Plates

The

feed

and

take-up

plates

can

be

adjusted

in

height

with

respective

sliders.

They

should

be

adjusted

such

that

the

tape

runs

in

centrally

between

the

flanges

of

the

tape

spools.

Erase

Head

The

height

of

the

erase

head

can

be

adjusted

by

turning

the

screw

(G).

The

adjustment

should

be

made

such

that

the

upper

edge

of

the

core

extends

about

0.1

mm

above

the

upper

edge

of

the

tape.

Record/Playback

Head

The

height

of

the

record/playback

head

can

be

adjusted

with

two

grubscrews

(C).

The

upper

edge

of

the

core

packet

in

the

record/playback

head

should

be

flush

with

the

upper

edge

of

the

tape.

Furthermore,

it

is

important

to

make

sure

that

the

head

face

is

vertical,

i.

e.

that

it

is

aligned

parallel

to

the

drive

capstan.

After

every

mechanical

readjustment,

the

head

must

be

rocked-in

(screw

D)

with

the

help

of

a

test

tape.

Rubber

Roller

Pressure

Lever

(RP-Lever)

Clearance

of

Roller

Holder

When

the

tape

drive

button

(start

button)

is

pressed,

the

long

thrust

rod

for

the

head

carrier

plate

mechanism

is

moved

via

an

actuator

bracket.

It

is

thereby

important

to

make

sure

that

the

lower

sheet

metal

section

of

the

RP-lever

rests

firmly

against

the

second

tape

guide

(with

slight

excess

excursion)

when

the

start

button

is

pressed.

If

this

condition

is

not

satisfied,

then

the

excursion

of

the

thrust

rod

must

be

adjusted

accordingly,

by

inserting

metal

washers

between

the

actuator

bracket

and

the

thrust

rod.

The

spring-loaded

roller

holder

should

have

a

clearance

of

about

1.

mm

with

respect

to

the

right

edge

of

the

RP-lever

in

the

pressed-in

state,

in

order

that

the

rubber

pressure

roller

can

operate

without

hindrance.

On

the

right,

the

clearance

of

the

roller

holder

with

respect

to

the

rapid

stop

lift-off

device

should

be

about

2

mm.

a

Measuring

and

Adjusting

the

Rubber

Roller

Pressure

Measurement:

The

pressure

of

the

rubber

roller

should

be

measured

with

a

tape

inserted

and

the

tape

drive

button

de-

pressed.

Apply

a

contactor

or

a

spring

balance

(1000p)

to

the

right

end

of

the

roller

holder.

Therewith

lift

off

the

rubber

roller

from

the

tape

and

drive

capstan,

and

slowly

return

it

to

the

tape,

parallel

to

the

drive

capstan,

until

the

tape

just

commences

to

run.

The

reading

should

then

be

660

to

730

p,

corresponding

to

a

roller

pressure

of

900

to

1000

p.

Adjustment:

The

force

of

the

pressure

spring

can

be

adjusted

by

turning

the

nut

(H).

Fast

Forward

Drive

In

the

“Stop“

setting,

the

clearance

between

the

right

inter-

mediate

wheel

and

the

right

engagement

plate

should

be

greater

than

0.5

mm.

The

tension

spring

for

the

fast

forward

drive

should

be

hooked

in

such

that

a

force

of

1100

+

100

p

results

when

the

right

intermediate

wheel

engages

the

brake

plate.

This

force

must

be

measured

with

a

contactor

at

the

measuring

point

opposite

to

the

hook-in

toothing

on

the

lever.

The

fast

forward

drive

button

must

not

be

pressed

for

this

measurement.

Fast

Rewind

In

the

setting

“Stop",

the

clearance

between

the

left

intermediate

wheel

and

the

left

engagement

plate

should

be

greater

than

0.5

mm.

Measuring

the

Friction

Wheel

Pressure

The

friction

wheel

is

situated

between

the

right

take-up

wheel

and

the

flywheel

disc.

During

playback,

the

force

with

which

the

intermediate

wheel

is

pulled

against

the

flywheel

disc

and

the

take-up

plate

should

lie

between

160

and

200

p,

as

measured

in

the

direction

of

the

pull-in

force

at

the

measuring

point

A.

When

the

unit

is

lying

horizontal,

these

values

increase

by

about

50

p

(self

weight

of

slider).

The

intermediate

wheel

slider

must

move

lightly.

Slipping

Clutch

(50

mm

diameter

measuring

spool)

The

upper

slipping

clutch

in

the

feed

plate

and

take-up

plate

assemblies

is

adjusted

with

the

star

spring

such

that

a

slip

torque

of

1100

to

1500

pem

is

obtained,

corresponding

to

a

force

of

440

to

600

p.

The

slip

torque

of

the

lower

slipping

clutch

of

the

left

feed

plate

assembly

should

lie

between

100

and

140

pcm,

corresponding

to

a

force

of

40

to

60

p.

The

lower

slipping

clutch

in

the

right

take-up

plate

assembly

is

adjusted

with

the

three

star

springs

such

that

a

slip

torque

of

330

to

470

pem

is

obtained,

corresponding

to

a

force

of

130

to

190

p.

The

auxiliary

brake

on

the

right

bottom

feed

plate

is

adjusted

with

the

tension

spring

such

that

the

braking

torque

in

the

rewind

setting

is

100

to

180

pcm,

corresponding

to

a

force

of

40

to

70

p.

Measuring

the

Tape

Tension

The

felt

pad

pressure

on

the

record/playback

head

should

be

40

to

60

p.

The

following

tape

tension

values

are

permissible

for

recording

and

playback

operation:

‘

at

start

of

tape:

greater

than

30p

at

end

of

tape:

less

than

140p

The

measurement

should

be

made

during

playback

operation.

The

rubber

pressure

roller

must

thereby

be

lifted

off

the

drive

capstan.

After

inserting

a

full

or

nearly

empty

18

cm

diam.

tape

reel,

respectively,

pull

the

tape

with

hooked-in

spring

balance

(250

p)

past

the

heads

and

the

drive

capstan

to

the

right,

with

about

the

nominal

speed

of

9.5

cm/s.

The

tape

tension

fluctuations

over

any

one

full

revolution

of

the

left

engagement

plate

should

not

exceed

+

5

p

about

the

mean

value.

Brakes

It

is

important

to

ensure

that

the

brake

linings

and

the

brake

surfaces

of

the

feed

and

take-up

plates

are

clean.

When

neces-

sary,

they

must

be

cleaned

with

isopropyl

alcohol.

In

the

resting

state,

the

stop

brakes

must

wedge-in

securely.

In

order

to

ensure

this,

a

clearance

of

1

mm

must

exist

between

the

ends

of

the

brake

slider

plate

and

the

brake

levers

at

the

points

E.

Adjust

the

sheet

metal

ends

accordingly.

With

the

tape

drive

button

actuated,

the

clearance

between

the

brake

rubber

and

the

feed

or

take-up

plate

must

be

greater

than

1

mm.

the

auxiliary

brake

on

the

supporting

plate

of

the

left

feed

plate

assembly

must

lift

off

when

‘the

rewind

button

is

pressed.

In

all

other

operating

states,

the

auxiliary

brake

must

restrain

the

supporting

plate.

Fig.5

Depiction

of

the

head

carrier

plate

Quick

Stop

When

the

quick

stop

button

“Pause“

is

actuated,

the

left

feed

plate

assembly

is

restrained

with

the

cork

auxiliary

brake,

the

tape

transport

is

arrested

by

lift-off

of

the

rubber

pressure

roller,

and

then

the

right

take-up

plate

is

stopped

by

lift-off

of

the

friction

wheel

from

the

flywheel

disc.

A

functional

check

of

this

process

can

be

made

by

pressing

the

quick

stop

button

slowly.

If

the

given

order

of

events

is

not

maintained,

then

the

tab

(B)

which

points

from

the

quick

stop

plate

towards

the

chassis

must

be

bent

accordingly.

Adjusting

the

Tape

Speed

Selector

Mechanism

When

the

selector

toggle

lever

is

actuated,

the

metal

slider

for

the

equaliser

changeover

switch

is

moved

at

the

bottom,

and

the

switching

rocker

for

the

belt

is

moved

at

the

top.

The

metal

slider

for

the

equaliser

changeover

switch

must

move

lightly.

It

should

jump

immediately

to

the

final

setting

when

switching

over.

If

necessary,

the

glide

points

of

the

slider

should

be

lubricated

with

Molykote

Paste

G

Rapid.

The

belt

switching

rocker

must

be

adjusted

such

that

the

belt

does

not

scrape

against

the

rocker

in

either

one

of

the

two

tape

speed

settings.

If

necessary,

adjust

as

follows:

first

of

all

switch

to

19

cm/s

and

adjust

the

long

leg

of

the

switching

rocker

such

that

the

belt

runs

centrally

in

the

slots

of

the

rocker.

Then

repeat

the

same

adjustment

after

switching

over

to

9.5

cm/s,

but

in

this

case

judiciously

bend

the

adjustment

nose

of

the

toggle

lever

which

bears

against

the

switching

rocker.

Adjusting

the

Drive

Capstan

Bearing

Block

Adjustment

is

here

necessary

when

the

bearing

block

has

been

released

or

replaced.

The

drive

capstan

runs

at

the

top

in

a

plastic

prismatic

bearing

and

at

the

bottom

in

a

self-aligning

sintered

bearing.

The

capstan

has

a

play

of

about

0.5

mm

in

the

upper

bearing

as

long

as

the

drive

button

is

not

actuated.

The

drive

capstan

is

pressed

into

the

prismatic

profile

and

thereby

takes

up

its

precise

nominal

position

parallel

to

the

magnetic

heads

and

tape

guides,

only

when

the

drive

button

is

actuated

and

the

rubber

pressure

roller

pushes

the

capstan

against

its

bearing.

The

adjustment

should

be

carried

out

with

the

drive

button

(start

button)

pressed

and

with

the

screws

of

the

bearing

block

tightened

moderately.

For

this

purpose,

use

a

depth

gauge

to

measure

the

clearance

between

the

head

carrier

plate

and

the

turned

step

of

the

flywheel

disc

at

three

well

spaced

points.

If

these

clearances

are

unequal,

make

them

equal

by

adjusting

the

bearing

block

accordingly.

If

a

repair

task

makes

it

necessary

to

release

the

bearing

block,

it

is

advisable

first

of

all

to

mark

its

position

on

the

head

carrier

plate,

using

a

scriber.

Electrical

Measurements

and

Adjustments

Measuring

Equipment

Universal

Multimeter

(internal

resistance

about

50

kQ/Volt),

AF’

Signal

Generator,

AF-VTVM

or

Voltage-Calibrated

Oscillo-

scope,

AEG-TELEFUNKEN

Test

Tape

(Order

No.

50.89.107).

N.

B.:

For

signal

injection

from

the

AF

signal

generator

for

the

following

measurements,

pins

2

and

3

on

the

phono

jack

are

used

for

channel

1

and

pins

2

and

5

for

channel

2.

The

voltage

levels

here

required

are

readily

obtained

directly

from

the

AF

signal

generator,

without

special

voltage

divider.

Furthermore,

this

practice

avoids

false

readings

which

could

otherwise

result

from

ground

loops

between

the

AF

signal

generator

and

the

tape

recorder

when

injecting

signals

into

the

sensitive

input.

All

the

measurements

described

below

are

to

be

made

in

the

setting

“Stereo”

at

9.5

cm/s

tape

drive

speed.

Rocking-In

the

Record/Playback

Head

Before

inserting

the

test

tape,

degauss

the

heads

and

tape

guides.

Insert

the

test

tape,

rewind

it

completely

once

in

each

direction,

and

connect

the

VTVM

to

the

radio

jack

(pins

2

and

3

or

2

and

5).

With

the

screw

(D)

of

the

rocker

plate,

first

of

all

adjust

the

head

coarsely

during

playback

of

the

1

kHz

measuring

tone,

and

then

adjust

it

finely

during

playback

of

the

12

kHz

measuring

tone.

These

adjustments

must

be

made

separately

for

the

top

and

bottom

channel.

If

the

voltage

maximum

setting

for

the

one

channel

does

not

correspond

exactly

to

that

for

the

other

channel,

finally

set

the

head

to

a

position

about

midway

between

the

respective

maxima.

Checking

the

Playback

Frequency

Response

Insert

the

test

tape

and

connect

the

VTVM

to

the

radio

jack

(pins

2

and

3

or

2

and

5).

Take

readings

during

playback

of

the

test

frequencies

80

Hz,

1

kHz,

10

kHz,

12

kHz

(—20

dB).

The

readings

obtained

should

not

differ

by

more

than

+3dB

with

respect

to

the

reading

for

1

kHz.

Check

for

both

channels.

If

the

two

channels

give

different

readings

for

the

1

kHz

reference

signal

level

(full

level),

correct

by

adjusting

the

potentiometer

R

219.

This

matches

channel

2

to

channel

1.

Adjustments

of

the

Equaliser

Coils

and

Checking

the

Recording

Preemphases

Connect

the

AF

signal

generator

to

the

phono

jack

(pins

2

and

3)

and

the

VTVM

to

the

stereo

earphones

jack

(pins

2

and

3).

Short

circuit

points

1

and

6

of

the

oscillator

coil,

turn

up

the

drive

level

control

to

maximum

and

switch

the

unit

to

recording.

Inject

a

1

kHz

signal

at

such

a

level

(about

t0

mV)

that

the

VTVM

reads

150

mV.

Without

altering

the

input

level,

then

tune

the

AF

signal

generator

to

14.5

kHz.

Adjust

the

core

of

the

coil

L

102

for

maximum

voltage

reading.

The

voltage reading

then

obtained

on

the

VTVM

should

increase

by

about

14

to

20

dB

(to

0.75

to

1.5

V)

at

14.5

kHz,

and

by

about

0

to

3

dB

(to

150

to

220

mV)

at

50

Hz.

The

measurements

must

be

repeated

for

the

second

channel,

with

signal

injection

at

the

phono

jack

(pins

2

and

5)

and

the

VTVM

connected,to

the

stereo

earphones

jack

(pins

2

and

5).

In

this

case,

the

coil

L

202

should

be

adjusted.

Adjusting

the

Tuned

Trap

Coils,

L101

and

L201

This

adjustment

is

necessary

when

oscillator

components

or

the

erase

head

have

been

replaced.

Connect

the

VTVM

to

L

101

/

R

113

or

to

L

201/R

213

and

chassis,

and

switch

the

unit

to

recording.

Adjust

the

core

of

the

coil

L101

or

L201

for

maximum

voltage

reading.

C

131

10000

pF

top

short-circuit

here

looking

onto

the

components

side

of

the

amplifier

board

Fig.6

Short-circuiting

the

oscillator

coil

Checking

the

Frequency

Response

,,Over

Tape“

For

the

recording

process,

connect

the

AF

signal

generator

to

the

phono

jack

(2

and

3);

for

the

playback

process,

connect

the

VTVM

to

the

radio

jack

(2

and

3).

Insert

the

test

tape

and

wind

forwards

up

to

the

unrecorded

section.

Switch

the

unit

to

recor-

ding,

turn

up

the

drive

level

control

to

maximum,

and

with

an

input

voltage

of

5

mV

first

of

all

record

at

1

kHz

and

thereafter

at

14

kHz.

These

two

frequencies

should

be

reproduced

at

the

same

level

during

playback.

If

the

playback

levels

are

found

to

differ,

repeat

the

recording

after

slight

displacement

of

the

bias

trimmer

C

12

for

channel

1.

Reduction

of

the

trimmer

capacitance:

increased

treble

response

Increase

of

the

trimmer

capacitance:

decreased

treble

response

These

measurements

and

adjustments

must

be

carried

out

a

IGS

analogously

for

the

second

channel

too.

(Adjustment

of

the

bias

trimmer

C

22,

recording

input

at

phono

jack,

pins

2

and

5,

and

'

playback

output

at

radio

jack,

pins

2

and

5).

It

is

advisable

to

carry

out

a

check

measurement

of

the

frequency

response

at

19

cm/s

tape

drive

speed.

Here

the

level

for

1

kHz

may

show

a

maximum

discrepancy

of

+3dB

with

respect

to

the

level

for

15

kHz,

corresponding

to

a

voltage

ratio

factor

of

0.7

to

1.4

at

1

kHz.

Adjusting

the

Recording

Level

The

recording

drive

manual

controls

must

be

set

to

maximum

for

the

following

adjustments.

Adjusting

the

VU-Meters

in

the

Stereo

Setting

Connect

the

VTVM

to

the

stereo

earphones

jack

alternately

to

pins

2—3

and

2—5.

From

the

AF

signal

generator,

feed

a

signal

at

1

kHz

into

the

phono

jack,

pins

2—3

and

2—5,

at

such

a

level

(about

225

mV)

that

the

VTVM

indicates

2

V

on

channel

1.

Check

by

transferring

the

VTVM

to

channel

2;

the

reading

here

should

also

be

2

V.

With

this

input

voltage,

adjust

the

preset

controls

R

151

and

R

251

such

that

the

pointers

of

the

VU

meters

are

on

the

dividing

lines

between

the

red

and

black

sectors.

Adjusting

the

Recording

Level

for

Stereo

Without

changing

the

input

voltage,

make

a

stereo

recording

on

the

free

section

of

the

test

tape.

Upon

playback,

channel

1

as

well

as

channel

2

should

both

give

the

noted

test

tape

level

+

3dB.

In

case

of

discrepancy,

repeat

the

test

recordings

after

having

appropriately

readjusted

the

preset

potentiometer

R

102

for

channel

1

or

the.preset

potentiometer

R

203

for

channel

2.

Adjusting

the

Recording

Level

for

Mono

2

Without

changing

the

input

voltage,

make

a

recording

on

the

free

section

of

the

test

tape.

Playback

of

this

recording

should

again

produce

the

test

tape

level

+

3dB.

If

this

is

not

the

case,

repeat

the

test

recording

after

appropriate

readjustment

of

the

preset

potentiometer

R

103.

Alignment

of

the

Output

Stages

Measure

in

the

playback

seting

without

signal.

The

collector-emitter

voltages

should

be

equal

(center-point

voltage)

in

both

of

the

two

output

stages.

Alignment

of

the

Oscillator

Frequency

In

the

setting

“Stereo”

recording,

tune

the

oscillator

coil

L

103

such

that

the

oscillator

runs

at

85

kHz

(+

4

kHz).

Circuit

Description

Connection

of

the

amplifiers

to

the

heads

and

output

stages:

Parallel:

Both

head

systems

are

connected

to

the

parallel-con-

nected

amplifiers.

Both

output

stages

are

driven

from

the

amplifier

1.

Each

head

feeds

one

respective

amplifier

chain.

The

output

stages

can

be

used

to

monitor

the

signals

ahead

of

the

tape

during

recordings.

The

particular

selected

head

system

(1

or

2)

is

con-

nected

to

amplifier

1

and

both

output

stages

are

driven

from

amplifier

1.

For

recording,

only

amplifier

1

switches

to

recording

and

the

output

stage

1

serves

for

monitoring

during

recording,

whilst

the

output

stage

2

is

then

switched

off.

The

other

(nonselected)

head

system

is

connected

to

amplifier

2.

According

to

the

direction

of

transcription,

the

signal

pick-up

(playback

function)

head

system

is

connected

to

amplifier

2,

which

remains

in

the

playback

setting,

whilst

amplifier

1

switches

to

recording

when

the

recording

button

is

pressed.

The

mixed

signal

can

be

monitored

via

the

output

stage

1.

The

output

stage

2

is

switched

off.

Stereo:

Mono:

Multi-Play:

Earphones

Outputs

The

signals

being

handled

by

amplifier

1

can

be

monitored

at

the

mono

and

stereo

earphones

output,

whereas

the

signals

being

handled

by

amplifier

2

can

be

monitored

only

at

the

stereo

earphones

output.

Amplifiers

The

combined

recording

and

playback

amplifier

is

a

five-stage

circuit

for

each

channel.

The

input

stage

(T

101

/

T

201)

is

driven

directly

via

a

coupling

capacitor

(C

102

/

C

202)

for

radio

or

microphone

recordings.

For

recordings

from

a

record

player

or

tape

source,

the

input

voltage

is

reduced

via

a

2.2

MQ

series

resistor

(R

1

/R

2).

Current

negative

feedback

is

applied

to

this

stage

via

an

unbypassed

emitter

resistor,

and

also

AF

negative

feedback

is

applied

from

the

output

to

the

input.

This

establishes

the

dynamic

input

impedance.

The

stage

will

accept

signals

40

dB

greater

than

normal

without

overloading,

and

it

possesses

a

favourable

signal/noise

ratio.

The

drive

level

control

(separately

R11

and

R

21)

lies

beyond

the

input

stage.

R

11

is

used

to

adjust

the

drive

level

for

the

monaural

recording

functions.

R

11

also

serves

as

drive

level

control

for

the

new

recording

in

the

multi-

playback

setings,

irrespective

of

whether

this

recording

is

taking

place

on

channel

1

or

on

channel

2.

Similarly,

the

volume

of

the

channel

to

be

transcribed

(1

or

2)

is

always

adjusted

with

R

21.

A

buffer

stage

with

collector

output

(T

102/T

202)

lies

ahead

of

the

equaliser.

The

gain

of

this

stage

in

channel

2

can

be

ad-

justed

with

R219

for

playback,

in

order

to

compensate

once

and

for

all

for

differences

in

sensitivity

of

the

record/playback

heads

1

and

2.

Furthermore,

the

sensitivity

switching

between

playback

and

recording

is

effected

in

this

stage.

A

switched

RLC-network

provides

equalisation

for

recording/

playback

and

19/9.5

cm/s

tape

speeds.

This

network

is

connected

between

the

output

(C124

/C224)

and

the

emitter

resistor

(R

133

/

R

233)

of

the

first

equaliser

transistor

(T

103

/

T

203).

Among

other

functions,

this

equaliser

circuit

provides

strong

treble

lift

for

the

recording

process

and

it

also

ensures

a

level

overall

frequency

response.

The

(T

104

/

T

204)

com-

pensates

for

the

gain

loss

produced

by

the

equaliser

circuit.

The

final

stage

is

an

emitter

follower

(T

106

/

T

206)

and

provides

a

low

output

impedance

of

the

amplifier,

so

that

the

driver

stage

for

the

output

stage

and

the

VU-meter

circuit

can

be

connected

here.

In

the

multi-play

settings

of

the

function

selector

switch

(S3/S4/86),

the

coil

in

the

equaliser

network

previously

connected

in

parallel

with

the

emitter

resistor

of

the

equaliser

transistor,

is

now

disconnected

from

chassis,

but

only

in

the

amplifier

serving

for

playback

(always

channel

2).

The

treble

lift

is

therewith

removed

in

this

amplifier

and

the

tendency

to

instability

reduced.

In

addition,

a

RC

combination

(RQ

/ C

23)

directly

at

the

playback

head

damps

out

any

parasitic

oscillation

otherwise

produced.

The

signal

to

be

transcribed

is

fed

via

R118/C111

to

the

base

of

the

equaliser

transistor

of

the

recording

amplifier

(always

channel

1).

The

recording

voltage

is

coupled

out

via

C

126

/

C

226

and

fed

via

a

tuned

trap

(L101

—

C

104

/

L201

—C

204)

and

an

adjustable

series

resistor

(R

102

/

R103

/

R203)

to

the

record/playback

head

1

or

2.

The

tuned

trap

prevents

the

bias

voltage,

which

is

also

applied

to

the

recording/playback

head,

from

sending

a

current

back

into

the

amplifier.

The

series

resistors

serve

for

setting

the

AF

voltages

in

the

recording

process

such

that

the

playback

levels

are

equal

for

the

various

operating

modes.

The

Output

Stages

The

output

stages

are

driven

from

the

recording/playback

amplifier,

via

respective

volume

controls

(R12

/

R22)

and

tone

controls

(R

31

/

R

41).

The

driver

stage

operates

into

an

interstage

transformer.

The

driver

stage

is

stabilised

with

an

emitter

resistor

(R

307

/

R

407).

The

pnp

power

transistors

(T

302,

303

/

T

402,

403)

are

driven

in

antiphase

from

the

respective

trans-

formers

(TR

301

/TR

401).

The

loudspeaker

is

coupled

to

the

center

point

of

each

output

stage,

via

a

large

electrolytic

capa-

citor

(C

306,

C

406).

The

output

transistors

are

connected

in

series

for

DC

considerations,

so

that

a

47

Ohm

NTC

resistor

is

required

in

each

base

circuit.

The

56

Ohm

resistor

in

parallel

therewith

gives

the

stabilisation

curve

the

required

form.

The

harmonic

distortion

factor

is

further

reduced

with

the

negative

feedback

loop

from

the

center

point

of

the

output

transistors

to

the

base

of

the

driver

transistor.

The

output

stage

is

not

damaged

by

an

open-circuited

load,

but the

output

transistors

are

destroyed

by

short

circuits

across

the

output

load,

or

by

load

impedances

smaller

than

3.5

Ohms.

Chassis

shorts

from

the

tran-

sistor

casings

also

lead

to

immediate

destruction

of

these

transistors.

It

is

therefore

quite

essential

to

disconnect

the

mains

plug

before

commencing

work

on

the

output

stages.

Caution:

Continued

on

Page

17

ne

ee

Amplifier

Board

Looking

onto

printed

wiring

side

approx.

as

from

Serial

No.

32

600

\/

—

ay

R103

~

tito

R151

82

50k

=13,3V

001p

C131

©

C126

if

Ww

26”

:

©

e/e

@\

sim

8

19

20-21

Cis

2k

56k

|O

75k

ry

és

*

Oop

27K

ez

yan

C16)

0047)

ee:

4

iad

ec

4

00471

@z

iobp

@—u}e

5k

:

tot

:

ecm-e|

*

E

cn3

r

0058

i

ae

ex

8

720

8

“a:

@r

3

S60

[22k

aa

10

ez

\

ae

P.

L102

700

cin

C204,

2200

7

aed

male

©

x

Ox

C226

1

e-—-

©

2

B

C25.

47p

@ec

.

S

8

ots

Oo

2 3

@Rix}-e

JG:

s6k

|S

1k

@-

re)

3)

5

© @

els

\

e-z-e

27k

e-

oan

a]

cx

yume

©

SHO

6.

0p

os

.

ep

4...

e@—zz}-@

iss

Ua

tl

0201

2

R237,

g

x

u

3

220°

1

7

wy

S

Be

88

a

3

pnp

R416

e

9

47

©

Wire

Connection

C406

1000p

301

100k

Ccsailteaca?

es

Nd

€301

$80p

“a

¢

302

bist

~

e

ail

7800p

J

‘eo

©

H 7 1

a

Record

/

Playback

Head

f

Tone

Control

k

50Hz/60Hz

Changeover

Switch,

S121,

S$

12

II

Circuit

Diagram

magnetophon

204

E

g

Pp

b

Erase

Head

g

Loudspeaker

Connection

10

2

{

Function

Selector

Switch,

$3,

$4,

S6

F i

i ,

Bu

24

c

Drive

Level

Control

cetaimnen

€

S)

Be,

2

m_

Recording

Switch,

ae

stereo,

mono

i

1

stereo

d

VU-Meter

Ms

1,

Ms

21

h

On/Off

Switch,

S

11

Playback

Switch,

S

1

e

Volume

Contro!

i

Voltage

Selector,

S9

depicted

switch

setting:

playback)

a

=

AC

150

green

AC

122

green

AC

122

violet

AC

122

viet

AC

122

red

~

TT

ee

tel

LSS}

4-

¥

—

rath

=

ee

en

|

rs

Bu

26

an

25k

0k

L01

375331085-06

Bv/Py

rH

tes

1068

375301

088-068wPv

t

=>

cn

006;

2

w-10-12|

36

Playback

Recording

Voltage

readings

a

50

kQ/V

meter,

Fo

without

AF

signal

specified

as

obtained

with

RAG

18k 500

37.5331.085-06BW/Py

power

ratings

of

resistors

black

brown

rt:

red

ge:

yellow

qn:

green

Sw:

br:

AC

150

green

=

6.

Le

2b

1

(DeHten

n

Equaliser

Changeover

Switch,

S

301

¢

direction

of

viewing

(depicted

switch

setting:

9.5

cm/s)

o

Radio/Microphone

Switch,

S

2,

S

22

.

(depicted

switch

setting:

Radio)

Pp

setting

t

coloured

bar

All

switch

wafers

viewed

from

floor

of

unit,

depicted

switch

setting:

Parallel

q_

wafer

AC

175

302

Ye00p

u_

tape

end

contact,

S8

AC

123

green

AD

152

P

AC

123

green

AD

152

P

AD

152

P

AD

152

P

Tr

301

37.5061.

8

7702

267-01

4

a)

er]

Ms

I

8.2471.006-01

@

+

OS

0

THe

TH

eo

Teo

TF

12346567

BF

MHUBKUESB

a

&

3

©

8

ee

Ms

21

8,%21006

-01

Tr

407

375061.

042-16

Bv/

PV

—H-

2w

——o—

iw

a

1/3W

—l+-

sw

bl:

blue

vi:

violet

ws:

white

tp:

transparent

(colourless)

AC

122

green

AC

122

violet

AC

122

violet

AC

122 red

ac

124

PI

11

37021078-24Bv/Py

B30C

120/650

K6

power

consumption

about

60

W

sn

®

MO315C

at

eos

oe

eee

|

234567

@€@3

HON

RBUKEB

BT

B

202

|

a

wee)

~~

8.7361.207

-01

viewed

from

floor

of

unit

sam

1

ae

ya

5 :

6

’

6

°.

1

,

:

ie)

°

C2)

?

“—

“MS

wy

20V

30.0155.0B

reserve

the

right

to

make

circuit

modifications

=

10

Circuit

Diagram

magnetophon

204

E

a

Record

/

Playback

Head

f

Tone

Control

k

50Hz/60Hz

Changeover

Switch,

$121,

$1211

b

Erase

Head

g

Loudspeaker

Connection

10

2

{

Function

Selector

Switch,

$3,

$4,

S6

c

Drive

Level

Control

(minimum

42),

Bu4,

Bu

24

m_

Recording

Switch,

oi

stereo,

mono

i

-

;

h

On/Off

Switch,

S

11

201

stereo

approx.

as

from

Serial

No.

32

600

eae

ee

Playback

Switch,

$1

:

e

Volume

Contro!

°i

Voltage

Selector,

S9

depicted

switch

setting:

playback)

a

AC

150

green

AC

122

green

AC

122

violet

AC

122

violet

AC

122

red

-

ye!

yellow

Tt

4

tt

|

re

®

mid

aE

ae

Bu2

2

O86

O83

22m

tet)

(Htten

Equaliser

Changeover

Switch,

S

301

(depicted

switch

setting:

9.5

cm/s)

Radio/Microphone

Switch,

S2,

S

22

(depicted

switch

setting:

Radio)

setting

wafer

AC

175

AC

123

green

AC

123

green

s

direction

of

viewing

s_

All

switch

wafers

viewed

from

floor

of

unit,

depicted

switch

setting:

Parallel

coloured

bar

u_

tape

end

contact,

S8

am

ioral

Q

pec

par

4522

0033p

R143

560

ma

a

R102

or

37

533)

085-06

Bv/Py

1068

375331

085-06BWPv

L

SS

U

‘en

*8

©

303

2p

R403

wk

375061

Tr

401

]

042-16

Bv/PV

2n

wH-1-12]

10-12

Bes

|

346

6-10

+

[2-34-01]

2-3K-72

:

78

12

7-8-9112

3-2/5

3-10

Playback

Recording

=

a

50

k2/V

meter,

without

AF

signal

ene

ae

R103

Voltage

readings

specified

as

obtained

with

220

ry

c

Ms

8%21006-01

@

R247

1S

k

(DH

Le

37

8

%71006

-01

37,5331

085-068W/Py

L202

of

re

sw:

br:

rt:

ge:

gn:

AC

150

green

power

ratings

103

401

2p

2250p

C404

|

be

ie

|

srmnast.o1

+

Roos

2k

‘

sia

SOHz

Mo35C

11

power

consumption

about

60

W

37021078-24BV/Py

B30C

120/650

KE

i

y

—O1-

2Ww

—+1+-

1W

sistors

i

1/3W

++

4's

WwW

black

bl:

blue

brown

vi:

violet

red

ws:

white

yellow

tp:

transparent

green

(colourless)

AC

122

green

AC

122

violet:

AC

122

violet

AC

124

P

AC

122

red

yellow

~~

8.7361.207-01

We

reserve

the

right

to

make

circuit

modifications

a

es

Amplifier

Board

Looking

onto

printed

wiring

side

C131

a

L

(Oy

0A150

Oo

&

|

Le

igo

(=25v]

5

Onl

a

©

Sty

2

S101

=v

16

e

=

T1104

a

qoop

+

a7

am

C16

OOuTp

:

‘i

e—}}

“ee

Oop

@h1}-@

5k

@

€n3

i

0,068

p,

Ot

24

‘onl

7

Ce

GEL

56

=f

20

cm

ea...

£207

HS

\

=

ce

wy

Os

s

\

¥

fs

@

Olsx

°

FNS

2

\8

47k

©)

©

oo.

9

J0e

1

ay

“%

18

\/

@eee

e

4

e

1”

af

“3

g

22k

C2%

,,

101

=

1204

7206

,

1

e-h-©

@

Rate

oui

|

ee

Pr

Prcestany

ci

220k,

oe

33k

100p

pO

R26

+.

e

five

e

cure

|

T20

C202

206

at

onme

©

-—

“a

&

:

2p

™@)

=

bd

Bk

9

:

5

ad

C207

coat

Z

Sate

Te

isk

18.2k.[470.}N.

[22k

ee

8

6

u,

718.

mV

8E778mV

L102

@wire

Connectio

npn

YY

List

of

Replacement

Components

for

magnetophon

204

E

~

te

oo

A.

Cabinet

and

control

parts

1

lid,

compl.

339

005

603

M

3

screw

for

metal

plate

339 925

015

H+

4

rear

cover

(for

heads)

339

126

622

Cc

5

front

cap,

compl.

339

126

620

M

6

—

spring

for

lid

339

913

701

N

+

7

metal

covering

plate

339

120

606

L

8

knob

for

six

functions

selector

339

205

602

E

9

control

knob

339

200

605

B

10

screw

bushing

for

front

cap

339

949

009

N

+

10a

screw

bushing

for

metal

covering

plate

339949008

K

+

11

level

meter

339

370

601

M

12

Pause-button

339 210

620

V+

13

speed

changeover

knob

339 215

604

T+

14

push-button

red

(record)

339

210

614

W

+

15

push-button

STOP

339

210

619

W+

16a

push-button

PLAYBACK

339 210 612

W+

16b

push-button

FORWARD

330

210

613

W+

46c

push-button

REVERSE

339210611

W+

17.

push-button

assy.,

compl.

339

700

605

N

18

solenoid

for

tape

end

off

switching

339

340

603

G

19

case

slider

339

060 607

A+

20

sign

plate

for

sockets

339

070

607

E

21.

bottom

plate,

compl.

(metal)

339

010 603

J

22

~carrier

handle,

compl.

339 015

605

N

23

rubber

foot

with

screw

339

060

501

R

+

24

wooden

frame

with

speaker

grill,

without

handle

,

339 025

606

Y

25

speaker

grill

339

045

602

F

26

loudspeaker

339

320 605

N

28

cover

plate

for

pos.

21

339

870

617

P+

29

rubber

cap

for

tape

reel

339

220

602

P+

30

mains

switch

339

440

610

H

31

plastic

foot

for

wooden

frame

(on

the

corner

of

the

frame)

339

060

701

K

+

32

plastic

cover

for

sockets

plate,

from

serial

No.

346

286

22

339

126

625

U+

B.

Head

assy-plate

40

record/playback

head

G

415

339 350

603

QO

41

balance

plate

for

head,

compl.

339

725

708

A

42

erase

head

holder

339

725 710

P+

43

erase

head

L315

339

355 603

N

44

rubber

buffer

339 725 714

H+

45

head

assy.

plate

compl.

339

720

607

J

for

chassis

with

6

mm

capstan

339

720

707

R

46

brake

lever,

compl.

339 745 705

P+

46a

rubber

for

brake

lever

339

745

706

K+

47

tape

holder

(wire arch)

339 725

711

N

+

48

brake

slider

plate

339

825 712

T+

49

toggle

lever

339 825

713

A

50

humflap

339

725

709

A

51.‘

tape

guide

roller

339

725

712

G

52

bracket

for

capstan

bearing

with

bearing,

compl.

339

715

604

T+

52

bracket

with

capstan

bearing

for

chassis

with

6mm

capstan

339 715

707

T+

53

tape

end

contact

339

725

605

E

54

lever

for

Pause

switch

339

825

714

K+

55

~—rubber

idler

lever,

compl.

339

750

703

J

56

friction

wheel

slider

339

765

704

V+

57

friction

wheel

339760705

GG

C.

Turntable

60

disk

for

reel

339

740

708

A

61

turntable,

left,

compl.

339

740 712

I

62

turntable,

right,

compl.

339 740

711

J

=

ta

Pos.

iismn

Spare

part

Price

Nr.

No.

group

63

felt

strip,

229m

339

740

718

N

+

64

felt

strip,

176

mm

339

740

719

K

+

65

brake

lever

for

turntable

left

(Pause)

339

745

606

B

66

brake

lining

for

lever

339 745 607

H+

67

Ultramid-washer

for

turntable

axle

339 942

018

H+

68

felt

for

additional

brake

(turnable

right)

339

745

608

H+

69

sliding

block

339

740

722

K+

70

slider

for

height

adjusting

339

740 723

K

+

D.

Mechanical

parts

79

rod

for

brake

lever

(Pause)

339 825

718

P+

80

tape

speed

changeover

assy.

339

770

701

D

80a

_

switching

piece

for

pos.

80

(plastic,

black)

339

770

702

K+

81

rocker

339 770

703

V+

82.

motor

belt

339 730

707

F

82

drive

belt

for

motor

(new

type)

(for

all

sets)

339 730

711

E

83

motor

fan

with

drive

pulley

for

motor

belt

50/60

cps.

339

735

707

B

84

rubber

sleeve

for fan

339

735 708

V+

85

flywheel

belt

339

730

708

E

86

dust

protecting

ring

for

flywheel

339

715

603

K

+

86

dust

protecting

ring

for

flywheel

for

chassis

with

6

mm

capstan

339

715 708

K

+

87

Flywheel

339

710

604

oO

87

flywheel

for

chassis

with

6

mm

capstan

339 710

705

B

88

counter

belt

339

730

709

B

89

counter

339 780

701

L

90

capstan

bearing

(lower

part)

without

spur

bearing

339

715 608

D

90

capstan

bearing

(lower

part)

without

spur

bearing

for

chasis

:

with

6

mm

capstan

339

870

713

D

90a

spur

bearing

for

pos.

90

339

715

609

P+

90a

spur

bearing

for

pos.

90

for

chassis

with

6

mm

capstan

339 715 709

N

+

91.

blocking

rocker

339 825

711

K

+

91a

set

screw

for

blocking

rocker,

long

339 920

702

K

+

91b

set

screw

for

blocking

rocker,

short

339 920

701

H+

92

lifting

lever

339 870

705

P+

93

sliding

block

339

870

706

K

+

94

switching

lever

2

339

825

715

R

+

95

switching

lever

1

339

825

716

R

+

96

__ratched

for

selector

switch

339

825

709

N+

97

rubber

ring

for

intermediate

wheel

339

735

711

N

+

98

intermediate

wheel

339 760

704

G

99

speed

changeover

wheel,

metal,

for

chassis

with

8mm

capstan

339

760

707

G

99

speed

changeover

wheel,

metal,

for

chassis

with

6

mm

capstan

339 760

708

G

E.

Springs

105

1

set

of

springs

(5

each)

339 915

717

H

+

1

spring

for

head

balance

339

905

724

K

+

2

spring

for

hum

flap

339

915 714

R

+

3

pressure

spring

for

erasing

head

339905

723

H

+

4

spring

for

tape

guide

roller

339 915

704

R+

+

5

tension

spring

for

brake

lever

339

900

707

H

+

6

pressure

spring

for

rubber

idler

lever

339 905

706

K

+

7

pressure

spring

for

Pausebutton

339 905 725

K

+

8

tension

spring

for

friction

wheel

slider

339

900

703

H+

+

9

tension

spring

for

brake

slider

339

900

721

H+

+

10

torsion

spring

for

quick

stop

339

910

724

K

+

11

pressure

spring

for

toggle

lever

339 905 705

H+

+

12

tension

spring

for

toggle

lever

339 900

712

K

+

13

pressure

spring

for

speed

changeover

switch

339

905

722

K+

+

14

tension

spring

of

changeover

rocker

339

900

710

N+

erases

es:

LEE

TLE

ELLE

g

lL

CE

EE

MELEE

YELLE

IEEE

Lessecesessesteeeeeeeeteg

(gaseaTSTTEL

TCLS

SOLES

SS

ED

4

ty

yy

GW

JVEFEEEEEEEE?

geesessssessetetegeggy

Zz

105

Springs:

marked

with

cross

(+)

and

number

106

Thrust

Rods:

marked

with

dot

(°)

DOMM

wm mw

=_

Pos.

Spare

part

Price

Nr.

em

No.

group

+

15

tension

spring

for

brake,

left

339

900

619

K+

+

16

tension

spring

for

forward

lever

339

900

603

K

+

17

clamp

spring

for

switching

rod

339 915

713

H+

+

18

pressure

spring

for

connecting

rod

339

905

703

H+

+

19

pressure

spring

for

pushbutton

lever

339

905

707

K+

+

20

tension

spring

for

rest

flap

339

900

706

N

+

21

tension

spring

for

pushbutton

lock

339

900

723

K+

+

22

tension

spring

for

stop

button

339

900

724

K+

+

23

tension

spring

for

lifting

slider

339

900

711

K+

+

24

tension

spring

for

switching

lever

339900719

K+

+

25

tension

spring

for

notched

lever

339

900

705

N

+

26

tension

spring

for

recording

slider

339

900

722

K+

+

27

tension

spring

for

additional

brake

and

reverse

lever

339

900

602

P+

106

1

set

of

5

rods

(one

each)

339

825

717

B

1

set

of

plastic

washers

5

each

339 942

021

F

1

set

of

metal

washers

5

each

339

940

014

T

F.

Electrical

parts

110

sliding

switch

with

spring

339

440

603

Cc

111.

sockets

carrier,

compl.

339 420

605

L

112

bracket

with

mic.

sockets

and

2

switches

339

420

606

L

113

loudspeaker

socket

LB

3

339

540

001

Vi+

114

5

pole

socket

339

540 014

A

115

Radio/Micro-switch

339 440

604

A

116

distance

tube,

black

339 935

017

K

+

118

mains

lead

339 480

603

E

119

potentiometer

5

KOhms

R

12/22/31/41

339 500

608

F

120

potentiometer

25

KOhms

R

11/21

339

500

703

J

121.

mains

transformer

339

310

602

P

122

clamp

for

mains

lead

339 870

707

H

+

123

shaded

pole-motor

E98,

U

28/2

50/60cps.

339

300

607

Ss

124

voltage

selector

plate

339 410

607

|

125

six-functiones

selector

339

440

609

M

126/129

slider

for

switch

S

101/201

339

400

608

G

127.

distance

tube,

yellow

339

935 015

K

+

128

.

slider

for

switch

S

301

339

400

607

F

metal

holder

for

sliding

switches

S

101/201/301

339 870

703

K+

130

amplifier

plate

339

330

607

Zz

130

amplifier

plate,

compl.

(new

type)

339

330

709

Z

131

intermediate

transformer

339

315

614

K

132

power

plate,

compl.

339

335 606

Zz

132

power

plate,

compl.

(new

type)

339 335

703

Zz

Continued

from

Page

7

The

VU-Meter

Circuit

A

capacitor

(C

127

/

C

227)

is

connected

via

a

diode

(D101

/

D201)

to

the

output

(C124/C224)

of

each

amplifier.

The

negative

half-cycles

of

the

AF

output

voltage

cause

the

diode

to

conduct,

so

that

the

capacitor

rapidly

charges

via

the

low

forward

resistance

of

the

diode

to

the

peak

value

of

the

AF

voltage.

The

resulting

DC

voltage

causes

a

current

to

flow

via

a

preset

resistor

and

the

VU-meter

to

chassis.

The

discharge

time-constant

of

the

circuit

is

about

2.5

seconds

and

the

charging

time-constant

is

about

0.15

seconds.

The

Oscillator

The

single-ended

RF

oscillator

is

switched

on-for

the

recording

function

by

applying

the

supply

voltage.

The

transistor

T

107

operates

in

a

grounded

emitter

circuit

and

employs

inductive

positive

feedback.

The

oscillation

frequency

is

determined

chiefly

a

Item

oo

coe

133

oscillator

coil

339

345

603

H

134

variable

coil

339

345

604

G

135

ferrite

core

for

pos.

134

339

450

604

P+

136

pot

core

18x

14

for

pos.

133

339

450

603

F

137

thermistor

47

Ohms

20%

339

530

005

F

138

twin

ceramic

trimmer

B

15

/

80

N

1500

339 510

003

A

139

fuse

M

0.4

C

DIN

41

571

339

570

006

P+

140

fuse

M

0.315

C

DIN

41

571

339 570

005

P+

141.

selenium

rectifier

B

30

C

1200/650

K

6

339

520 016

|

142

bulb

fitting,

compl.

339

560

005

D

143.

miniature

bulb

24V

80

mA

339 560

002

Cc

144

variable

resistor

1

KOhms

R

312/412/219

339505

707

A

145

variable

resistor

10

KOhms

R

102/103/203

339505

703

B

147

variable

resistor

50

KOhms

R

151/251

339

505 702

B

149

electrolytic

capacitor

100

uF

15/18

V

ins.

C

124/224

339 584

032

A

150

electrolytic

capacitor

1800

uF

25

V

ins.

C

302

339 588

001

|

151

electrolytic

capacitor

1000

uF

25

V

C

306/406

339

586

018

L

152.

electrolytic

capacitor

100

uF

15/18

V

C

103

153

electrolytic

capacitor

100

wF

35/4

V

C

129

154

electrolytic

capacitor

250

uF

6/8

V

C

121/221

155

electrolytic

capacitor

250

uF

15/18

V

C

118/304/404

157

electrolytic

capacitor

10

wF

15/18

V

C

102/202

158

electrolytic

capacitor

25

uF

10/12

V

C

117/217

159

electrolytic

capacitor

25

uF

15/18

V

C

303/403

160

electrolytic

capacitor

25

uF

25/30

V

C

501

161

electrolytic

capacitor

50

uF

3/4

V

C

127/227

162

electrolytic

capacitor

50

uF

6/8

V

C

107/207

163

electrolytic

capacitor

100

uF

3/4V

C

112/119/212/219

164

electrolytic

capacitor

5000

uF

35

V

ins.

C

402

165

diode

OA

150D

101/201

339

584

026

B

339

584 017

Cc

339 586

002

A

339 586 003

B

339

582 006

A

339

582

010

Cc

339

582

015

A

339 582 016

B

339 584

013

D

339 584 012

A

339 584

028

A

339

588 004

M

339

527

002

A

by

the

inductance

of

the

coil

L103,

the

inductance

of

the

erase

head

and

the

capacitance

of

C

131.

The

different

loadings

of

the

oscillator

for

mono

or

stereo

operation

due

to

the

erase

heads

are

compensated

by

connecting

a

resistor

R10

or

a

capacitor

C1.

The

bias

voltage

is

fed

to

the

record/playback

heads

via

the

trimmers

(C

12

/

C

22).

End

Switch-Off

The

switching

foil

at

the

start

and

end

of

the

tape

closes

the

charging

circuit

of

an

electrolytic

capacitor

(C

501)

via

the

tape

end

contact

(S

8).

The

electrolytic

capacitor

lies

in

the

base

circuit

of

an

npn

transistor

which

is

thus

made

to

conduct

and

energise

the

stop

solenoid

for

the

duration

of

the

charging

process.

For

renewed

actuation

of

the

stop

function,

the

charging

circuit

must

first

be

broken

again,

so that

the

electrolytic

capa-

citor

can

discharge

through

R

501.

Telefunken M 204 E Operating and installation instructions

Popular Tape Deck manuals by other brands