Roberts 1640 Bedienungsanleitung

SERVICE

MANUAL

1B40-1B50-1BBDD-1B70

TAPE

RECORDERS

~

·

_;.

,,

~··

IMJ

$2.50

MODELS

1640,

1650,

1

6600,

1

670.

!KEYED

TO

ILLUSTRATION AT RIGHT!

1.

Supp

ly

Re

el

Hol

der

2.

Suppl

y Reel

3.

l e

ft

Chan

n

el

Spco~cr

(Not

in

1660D.

Ou

t

board

In

1670)

4.

Tope

Guide

Roller

5.

Automa

ti

c Shut-

Off

l

ever

6.

Drive

Cop1tan

S

tora

ge

Post

7. I

ndex

Count

er

8.

Editing

Guide

9. Ta

ke

-

up

R

eel

Ho

ld

er

I0. Toke-

up

Reel

I I . Right

((ronne

l S

peak

er

(Not

in

1660D.

Ou

tb

oa

rd

in

1

670)

12.

Drive

Capst

an

13. Pi

nc

h

Wheel

14.

Pau>e

leve

r

15

.

R

ewi~d

/

Fasl Fo

rwar

d Co

ntro

l

16.

Stop

/ Storl Co

n1

ro

l

17. l e

ft

Channel

Miaophonc

Inpu

t,

18.

Ri

ght

Cha

nn

el

Microphone

I

npu

t

19. l e

ft

Channel

Volume

C

on

trol

20.

le

ft C

hann

el VU

Meter

(Oual

Purpose

Me

t

er

on

Madel

1640)

21.

Modl!l

1

640

: le

ft

/ Rig

hi

VU Me

ier

S

wit

ch

Model.

1650

an

d 1

670

: Mo

nilor

-

Norma

i·

Mul

e

Speqkcr

Switch

Mod

el

1660D:

R/ l - NOI'I!IOI • l / R

Channe

l

Tr

ansfer

Sw

it

ch

22

. Right

Channe

l VU

Meter

(N

ot

in

Mo

d

el

1

640

)

23

.

Ri

gh

t

Channel

Vo

lume

Control

24. L

ef

t

Channe

l Play/ Record Sw

it

ch

25. Right Ch

anne

l

Ploy/

Record Sw

it

ch

26.

Ton

e Control

27

. Power Switch

28

. Record I

ndicator

li

gh

t

29

. Power

Cord

Conn

ectio

n

30

. St

ereo

He

adphone

J

ock

(

1650

&

16

70

J

31. Right Hum

Ad

justment

32.

l

eft

Hum

Adjustmen

t

33.

R

ight

ChoM cl Preornp Ou

tp

ut ( 164

0,

1650

,

1670

I

34.

l

C!

ft

Chonnel

Pr,omp

Outpu

t (

164

0,

1650

, 1

670)

35

.

Right

Channe

l Phono/ R

od

io

Inp

ut

36.

l

ei

I C

hann

el

PhonofRadio

In

put

37

. Ri

ghi

Cha

nn

el

Speaker

Output

(I

6

40

.

1650,

1670)

38.

Left

Channel

Sp

eake

r

Output

(

1640,

1650

,

1670)

39

. Right Channel

Tw

eeter

Oulpul

(

1650,

1670)

4

0.

Loll

C

hann

el TwDet

cr

Ou

t

put

(16

50,

1

670)

4 1. R

ig

hi

Cho nnol

High

Levol

Ou

t

put

II660D

on

l

y)

4 2. l

ei

I

Cllonnol

Hi

gh

Level

Ou

tp

ut (

1660D

o

nl

y)

43.

Ri

ghi

Channel

Low Level

Output

( 1

660

0 onl

y)

44

. l

ell

C

honn

al l

ow

level

Ou

tp

ut (

1660D

onl

y)

IDENTIFICATION

CHART

Ll

V)-

--"'~-

-

-,

{ll)

l--

--

-

-=-==='-'

FUNCTIONS

OF

CONTROLS

Power

Switch:

Moving

Lhe

power

switch

to

the

·'

ON

"

posilion

applies

power

to

the

motor

and

amplifier.

In

the

"

OFF

" position,

power

is

cut

off

to

the

entire

unit

.

Volume:

A

separate

volume

control is

provided

for

each

channel.

The

volume

control

varies

the

playback

vol

ume,

and

the

record

level

when

making

a recording.

Tone:

The

tone

control

setting

determines

the

[re

guency

r

e-

sponse

of both amplifiers.

Tone

controls do nut. work

during

record.

VU

Meters:

The

VU

Meters

are

used to

monitor

the

record

level

when

recording,

and

to

balance

stereo

play.

Meter

indication

sho

uld

be

between - 3

and

-7

for

best

recording

results.

Record

Switches

:

To

operate,

depress

either

or

both

record

switches,

then

t

urn

the

stop

/

start

conh·ol to

"start.

..

This

holds

the

record

switch

in

record

mode

.

When

the

stop

/

start

control

is retu

rned

to "

stop,

"

the

record

switch

automatically

snaps

back to

play

mode_

Channel

Transfer

Switch:

(1660

-D

)

This

switd1

inte

rnally

tr

ansfers

the

output

of

one

chan-

nel

over

to

the

input

of

the

other

channel.

A

microphone

or

radio

/

phono

addition

is

added

to

the

transfer

receiv-

ing

channel

during

recording.

The

process

may

be r

epeated

back

and

forth

between

c

hann

els

to

make

a

multiple

recording.

Tape

Lifter:

The

tape

lifter

is

under

the

head

cover

and

is

operated

by

the

stop

/

start

control.

When

the

stop

/

start

control

is in

stop

mode

,

the

lifter

pushes

the

tape

away

from

the

h

eads

to pr

event

excessive

wear

du

ring

the

fast

rewind

and

fru;t

forward

oper

ations.

This

also

mules

the

~ound

during

these

modes.

Stop-Start:

Starts

tape

movement

i11

"Play'

' or

"Record"

position.

Stops

tape

mo

vement

when

moved

lo

the

"Stop''

position.

Rewind

-

Fast

Forward:

Fast

Fo

rwa

rd

position

advances

U1e

tape

on

to

the

take-

up

reel

at

a

fast

rate

of speed.

Re

wi

nd

position wi

nds

the

tape

onto

the

feed

reel

at

a

fast

rate

of

speed

.

Pause

Lever:

In

t.he

"Up

' posilion,

pinch

roller

is moved

away

from

capstan,

and

take-up

tor

que

is r

emoved

from

take-up

spin-

dle.

Tape

stops

instantly.

This

permits

an

adjustm

ent

of

the

record

level

without

tape

movement.

\Vhen

lever

is re-

tmned

to

"Down"

position,

the

t

ape

movement

begins.

Index

Counter:

Pr

ovides a

means

of

locating

desired

select

ions

on

a

reel

of

tape

without

skipping

and

h

un

ting

.

Hum

Adjustment

Controls:

On

Lhe

l'

ear

paneL

lhe

A.C.

Receptacle

are

two

openings,

these

are

the

Right

and

Left

Channel

hum

ad-

justing

Potentiometers.

They

are

screw

driver

adjustment.>.

Without

tape

on

the

unit,

turn

the

volume

up

full

and

ad

-

just

the

cont

rols for

minimum

hum

on

each

ch

ann

el.

Auto-Stop

Switch:

When

tape

holds

the

aut

o-stop

switch

''U

p," the

motor

circuit is

completed

and

the

motor

runs.

If

the

tape

br

ea

ks,

runs

out,

is

of

insufficient

tension,

the

switch

lever fails,

breaking

the

circuit,

shutting

off

the

motor.

IN

PUT

AND

OUTPUT

JACKS

Microphones

:

A

microph

o11e

input

is

provided

for

each

channel.

These

input

jacks

are located on

the

front

panel

to

the

left

of

the

left

cha

nn

el

volume

control.

Note:

When

using

the

P

hone-Radio

inputs,

the

mi-

crophone

plugs

must

be removed from

the

mi-

crophone

jacks.

Phono-Radio

Input:

Each

channel

is

provided

with

a

Phono

-Raclio

input

for

making

direct

rec

o

rdin

gs

from

a radio.

phonograph,

or

tuner.

Th

ese

inputs

are

located

on

the

rear

panel.

Outputs:

1660D .

..

There

are

two

high

and

two low level

preamp

outputs.

each

adjustable

by

the

volume

cont

rols.

These

out-

puts

are

used

to collllect

the

1·ecorcler

playback

system

to

an

external

power

amplifier.

The

output

jacks

are

located

on

the

rear

panel.

The

high

level

outputs

are

used

with

standard

tube

type

amplifiers

that

have

tu_ner,

auxiliar

y

or

othe

r high

level

inputs.

The

low level

outputs

are

for solid

state

amplifiers

.

Te5ts will show

which

is

best

for

each

individual

case.

The

high

and

lo

w level

outputs

are

low

impedance

cath-

ode

follower

outputs

allowing for

lvnger

interconnecting

c.:ables

without

l

ine

losses.

1640

..

. On

the

rear

(Janel

are

two

external

speaker

jacks

and

two

high

impedance

pr

eamp

outputs.

1650 & 1670 . . .

Ha

s

the

same

outputs

as

the

1640,

plus

two

phono

type

jacks

for

extension

speakers

to

work

with

the

internal

speakers.

There

is

also

a

stereophone

jack.

3

4

PARTS

IDENTIFICATION

Fig.

2.

Top

View

of

Tape

Transport.

OPERATING

INSTRUCTIONS

Hook-Up

Procedures:

(1660-D)

1. T

he

outputs,

high

and

low level

ar

e

cathode

follower.

low

impedance

preamp

outputs.

Th

e

instructions

of

the

externa

l

power

amplifier

and

or

t

un

er

should

be

followed.

However

as

a

rou

gh

guide

the

following

may

be

helpful.

I

nterconnecl

..

. .

Hi

gh

l-ev

el

Output

..

. to

..

Tube

amplifier

.

·

a.

Hi

gh

level i

np

ut

b.

Auxillary

input

c.

Preamp

input

d.

Tuner

input

Low

Level

Output

...

to

..

Transis

tor

amplifier.

a.

Input

b.

Preamp

input

c.

Tu

ne

r

input

d.

Auxiliary

input

Rad

/

Ph

ono

I

nput

...

to

..

Tuner

Output

to

..

Amplifier

T

ape

Ou

t

to

..

Amplifier

Pr

eamp

Out

to . . P hono.

Ceramic

Cartridge

to

..

Ph

ono.

Pr

ea

mp

Out

to

..

parall

el w

ith

TV

spe

aker

s

to

..

parallel

wit

h

Radio

speakers

Thread

i

ng

the

Tape:

1.

Place

a full

reel

of

tape

on

feed

spindle.

P

lace

an

empty

re

el

on t.ak

eup

spindle.

Secure

reels

in

place

with

rubber

r

ee

l

holders

provided.

2.

Unwind

aboul

14

inches

of

tape

from

feed r

ed.

H"old a

section

of

tap!'

taut

and

thread

p

er

ph

oto

.

Make

sure

!.ape

pulls

automatic

tape

shutoff

switch

arm

u p

to

"On

"

p

o.>

ition.

3. T

nsPrt

fre~t

end

of

tape

into

one

of

t

he

r

adial

slots

in

hub

of

takeup

reel. Ho

ld

tape

end

in

place

and

turn

r

eel

seve

ral

turns

co

un

terclockwise to

secure

tape

to

the

reel.

To

Make

a

Stereo

Recording:

1.

Connect

reco

rder

to 110-125 volt 60 cycle

po

wer

so

ur

ce

with

power cord provided.

Tur

n power s

witch

to

"

Po

wer

On.''

2.

Thread

the

t.ape.

Set

Index

Counter

to

zero.

3. Co

nn

ect

signal

sou

r

ce

to

proper

input.

a.

If

microphones

ar

e

used

connect

them

to

microphone

jacks. Level will

be

contro

lled

by

the

vo

lum

e c

ontrols

.

Fig.

3.

Bottom

View

of

Tape

Transport.

b.

If

a

phono

or

radio

source

is

used

connect

their

out-

puts

to

the

respective

channel

Phono

-

Radio

input

jacks. Level will

be

controlled

by

the

volume

controls.

4.

Push

Pause

Lever

to

"Up"

position.

!i.

Hold

record switches depressed.

6.

Tum

start

/

stop

c

ontrol

to "

Start"

po

s

it1

on.

This

hold;;

the

record

switches down

in

record

mode.

7.

Start

signal

so

ur

ce to

set

recording

level.

VU

Meters

should

read

-3

to - 7 on

the

average

.

8.

Release

the

Pause

Lever

(down)

to

start

tape.

Tracks

1

and

3

are

now being recorded.

9.

When

recor

ding

is

completed,

or

when

the

end

of

the

reel

of

tape

is

reached,

return

start

/

stop

control

to

·

'Stop''

position.

Record

switches

are

automaticaUy

re-

leased

to

r

eturn

to

play

position.

10. T o

record

tracks

2

and

4, remove full reel from

take-up

spind

le

.

turn

over

and

pl

ace

on

supply

spindle.

Proceed

as

in

steps

2 - 9.

To

Play

a

Stereo

Recording:

1. Co

nnect

recorder

to

proper

power

sour

ce

with

power

cord

provided.

Turn

power

switch

to

"Power

On."

2.

Thread

the

tape.

Set

Ind

ex

Counter

to zero.

3.

Locate

desir

ed

start

i

ng

point

by

using

Fast

Forward-

Rewind

kn

ob

while

observing

Index

Counter.

4.

Turn

Start-Stop

knob to "

Start"

position.

Adjust

volume

for

each

channel.

Both

tracks

of

a

2-track

ste

reo

tape

or

tracks

1

and

3

of

a

4-track

stereo

tape

will

now

be

played.

5.

Tape

may

be

advanced

rapidly

or rewound,

after

Start-

Stop

knob

is

placed

in

·

·stop

" position,

by

using

F

ast

Forward-Rewind

knob.

6.

To

play

tracks

2

and

4 of a 4

-track

stereo

recording

after

tracks

1

and

3

have

been

completed

,

do

not

rewind

tape.

Remove

full ree\ from

ta

keup

spindle,

turn

it

over.

and

place

on

feed spindle.

Proceed

as

in

Steps

2-5 above.

Monaural

Recording

and

Play

bac

k:

Proceed

as

indicated

for

stereo

operation

but

use

only

jacks.

contro

ls

and

switches for

one

channel.

Volume

con

-

trols for

the

unused

c

hannel

should

be

set

at

ze

ro.

To

record four

monaural

tracks.

use

left

channel

f

ir

st.

recording

track

1.

Reverse

tape

by

removing full r

eel

from

Lakeup

spindle,

turning

it

over.

and

placing

it

on

the

feed

spind

le.

Continue

to

use

left

ch

annel

while

recording

track

4.

Reverse

tape

and

use

right

channe

l

to

record

track

3.

Rever.se

tape

again

and

continue

to

use

right

channel

in

order

to record

track

2.

To

play

back

four

monaural

tracks.

use

the

same

sequence

of

tape

sides

and

recorder

channels

as

when recording.

5

6

SOUND

-

WITH-SOUND

RECORDING

This

is a

procedure

by

whi

ch

you

may

record

yam

fa

vorite

orchest

ra

on one

channel,

and

then

play

or

sing

with

t

he

re-

cording

in

suc

h a

manner

as

to

make

the

playback

sound

as

t

hough

you

were

"

right

there

..

with

the

orchestra

.

Or

it

ma

y

be

used

for

language

study.

with

the

teacher

's

voice on one

channel

and

your

re

spo

nses which

may

be

erased

and

re-re

corded

as

often

as

desired)

on the o

ther

channel.

ROBERTS

Langua

ge

Lab

o

rator

y

Tapes.

available from

your

Robe

rts

de

aler

,

have

tne

instru

cor's

voice

pre-recorded

in

this

manner

in fo

ur

differe.

nt

language

s.

PROCEDURE:

1.

Make

a

master

recording on

Trac

k 1.

using

Left

chrumel

only

.

Turn

Right

channel

volun1e

controls

to zero

and

fol·

low

procedure

m1der "

To

Make

a

Stereo

Recording

,"

using

L

eft

channe

l only.

2.

Rew

ind

tape

.

3.

Re

co

rd

on

Track

3,

using

Ri

gh

t

ch

ann

el

only

while

listening

to

Track

1.

4.

Rewind

t.ape.

5.

Play

back

re

co

rd

ing,

as

in

stereo

play

.

Master

rec

or

din

g will

be

heard

on

L

eft

channel

and

added

reco

rding

will

be

heard

on

the

Ri

ght

ch

ann

el.

6.

Track

3

may

be

erased

and

r

ereco

r

ded

without

di

s

turbing

master

t

rack

by

repeating

Steps

2

through

4.

SOUND-ON-SOUND

RECORDING

(1660D

ONLY)

1.

Make

original

recor

ding

on

Track

1

usi

ng

L

eft

channel

only.

Turn

Right

channel

volume

cont

rol to ze

ro

and

follow

proced

ur

e

unde

r, ''To

Make

a

Stereo

Recording."

2.

Re

wind

tape

to

be

ginning

of

original

recording.

3.

Set

Channel

Tran

sfer

Switch

io

"L

to

R" position.

4.

Pu

sh

Pa

use

Lever

up

to

"

Stop

'' position.

5. H

old

Ri

g

hi

Reco

rd

Switch

depressed

and

turn

Start-St

o p knob

to

"S

tart''

posi

tion

.

6.

Connect

Right

challllel

microphone

.

Appl

y

sig11

al

to

microphone

and

ad

just

the

Ri

ght

cha

nn

el

volume c

ontro

l

fo

r ap-

proximat

e

ly

half

the

normal

re

co

rding

level

re

ading

on

the

Right

c

hannel

VU

Meter.

7.

DO

N0'1'

READJUST

THE

RIGHT

CHANNEL

V

OL

UME

CO

NT

ROL

AFTER

PRESETTING

FOR

THE

MIC-

ROPHONE

RECORDING

LEVEL.

(V:!

•Jormal)

8.

R

elea~e

Pau

:e

L

ever

and

make a

tdal

recording

of

the

Lef

t

cba~el

trSllSfer

and

the

R

ight

channel

microphone

added

.

9.

Adjust

the

L

eft

channel

volume

cont

rol only, while

watching

the

Ri

ght

channel

VU

Meter

readin

g.

Th

e

Righ

t chan-

nel

VU

Meter

should

be

read

ing

full

normal.

Ha

lf

of

the

reading

will

be

the

L

eft

cbrumel

tr

ansfer

ru1d

the

other

half.

the

Ri

ght

channel

micr

opho

ne.

10.

Rewind

the

tape.

play

the

trial

recordin

g.

If

the

test

run

was

satis

fa

cto

ry.

proceed

with

the

final

recording

by

re-

peatin

g

St

eps

2

!hrcu

gh

9.

11.

Play

back

rec

ording. So

und

-

On-S

ou

nd

re

co

rdin

g is on

Tra

ck 3 (

Right

channel

) so volume

controls

for

Left

cha

nnel

sho

uld

be

set

to zero.

(N

OTE:

The

original

Track

l

recording

of

the

L

eft

amplifier

is

still

intact

at

this

point,

so

Step

s 2

through

9

may

be

repeated

if

the

final

re

cor

ding

was

no

t

satisfactory

.)

12.

The

abo\·e process

ma

y

be

repeated,

using

Tra

ck 3

as

the

original reco

rding

and

add

more

ma

te

rial

to

it

for a rnul-

tirl

e reco

rdin

g.

In

this

case

the

Channel

Transfer

Switch

should

be

se

t

at

"R to L" position,

and

the

L

eft

channel

microphone

input

will

be used.

ASSEMBLY

-

DISASSEMBLY

Assembly

(mounting):

(1660-D)

1. Check for

dearance,

(deck & prean1ps, reels,

ease

of

op-

eration.

etc.).

Transfer

cutout

pattern

from

template

to

panel.

C

ut

out

panel

open

ing.

2.

Rem

ove

side

angle

bra::k

ets

{rom

metal

cage.

3.

In

sta

ll

un

it

into

panel

cutout.

4. R

einst

all side

angle

brackets

onto

rne.tal c

age

,

and

press

up

against

underside

of

panel.

5.

If

panel

is

.1f2"

or

mar~

thick,

fasten

angle

brackets

from

underside

w

it

h wood screws,

into

panel.

6.

If

panel

is

less

th

an

1

/2"

thick

use

fanc

y

headed

bolts

and

nuts

clear

through

panel.

For

Access

to

Top

of

Tape

Deck:

l.

Remove

Start-Stop

Jmob

an

d

Fa

st

F

orw

ard

-R

ewin

d

kn

ob.

2.

Remove

3 tr

ansport

deck

mounting

screws, c

ap

sta

n bush-

ing

sto

ra

ge

r

ost

.

3.

Pr

y o

ut

pinc:hwheel

cap.

take o

ut

pinchwheel

mounting

screw.

and

lift

oU

pinchwheel.

4.

Remove

bc>th

reel tables

after

taking

CJ

ut

re

el

table

screws.

Note

hu

m

ber

of fibre

spacers

und

er

reel tables

as

th

ey

are

removed.

5.

Lift

off

transport

deck

panel.

MAINTENANCE

INSTRUCTIONS

LUBRICATION

L

ubricate

the

following

parts

every

th<ee

months

when

the

<eco

rder

is

subjected

to

heavy

usage.

every

six

months

under

mod

erate

usage,

and

once a

yea

r unde<

conditions

of

occasiona1 use.

l.

Feed

and

take-up

spindle

sh

af

ts

with

two

drops

of

light

machine

oil

on

each

shaft.

2.

Rewind

idler

bearing

and

wind

idler

bearing

.

with

two

dr

ops

of

Light

ma

ch

ine

oil

on

each

bea

r

ing

.

3.

Apply

a

liberal

amount

of

light

grease

to

each

roller

and

on

all

levers

and

cams

.

4.

Sa

tuTate

the

felt

washe

r

in

the

re

t

ainin

g

cup

of

the

drive

capstan

with

light

machine

oil.

Caution:

Do

not

allow

grease

or

oil

to

remain

on

any

of

the

drive

surf

ace

s,

or

on

plastic

su

rfac

es

or

any

part

touch-

ing

the

tape.

CLEANING

The

capstan,

pinchwbeel,

tape

guides,

and

.reco.rd/

play

head

and

erase

head

accumulate

a

tape

oxide

coating

as

the

ta

pe

passes

these

parts.

Clean

these

parts

pe

riodically

with

a

soft

cotton

swab

dipped

in alcohol.

MECHANICAL

ADJUSTMENTS

1.

Record-Play

Head

Heigh

t

-L

oosen

the

two

mounting

nuts

at

the

side

of

the

.he

ad

mounting

bra

cket.

Move

the

head

so

that

the

top

pole

piece

is

even

with

the

top

edge

of

the

tape.

Gently

tigh

ten

t

he

nuts.

Azimuth

-Pla

ce a

prerecorded

azimuth

alignment

tape

on

the

recorde.r.

While

playing

tape

alternately

t

ighten

up

per

and

loosen lo

wer

head

mo

u

nting

nuts

or vice

versa

until

position

of

maximum

output

is

found.

2.

Erase

Head

The

erase

b

ead

hei

gh

t is

adjusted

in

the

same

manner

as

th

e

Rec

ord

-Pla

y

head.

3.

Brake

Shoes

When

br

ake

shoes

become worn, loosen

the

mounting

scre

ws a

nd

rotate

the

shoes

a few

deg

r

ees

until

a

new

brake

surface

is exposed

to

the

supply

and

take-

up

reel

discs.

4.

Rewind

Idler

Wheel

To

bring

the

wheel

in

alignment

with

the

rewind

reel

shaft

adjust

both

the

idler

load

spring

and

the

rewind

roller.

The

press

ur

e on

the

knurled

motor

bushing

shou

ld

be

about

50 gr

ams

durin

g

th

e

rewind

operation.

5.

Pinch

Wheel

To

bring

the

wheel

in

ali

gnme

nt with t

he

capstan

shaft

adjust

th

e

pi

nch

w.heel

load

sp

r

ing.

The

pinch

whee

l

pres-

sure

shou

ld

be

between

1,000

and

1,150

grams

whe

n

the

unit

is

operating

at

7%

ips.

6.

Rewind

Intermediary

Idler

Adjust

the

intermediate

wheel

sp

ring

to

obtain

about

50 g

ram

s

of

pressure

equally

exerted

to

both

the

rewind

idler

wheel

and

the

rubber

ring

on

the

supply

reel

shaft

assembly

.

Make

adju

stment

in

the

r

ew

ind

mode.

7.

Supply

Spindle

Tension

A c

han

ge in

to

rqu

e is

accomplished

by

either

adding

another

metal

washer

the

one

in

the

clutch

assembly

which

increases

tension,

or

by

removing

the

exist

i

ng

one

w

hi

ch

has

the

reverse effect..

See

explo

ded view

for

location.

The

r

eq

uired

tensi

on

is

determined

by

placing

a s

tand-

ard

seven

inch

r

eel

with

a

two

and

one

fourth

(21,.4)

inch

hub

diameter

on

the

supply

spindle.

The

re

el

should

have

twenty

six

feet

of

leade.r

tape

wound

on

it.

Attach

the

end

of

the

leader

t.ape to a scale

with

a

range

of

0

to

250 g

rams.

Position

the

scale

vertically

with

respect

to

the

re

el

hori-

zontal

axis.

Exert

a

ste

ad

y pulL

The

r

equ

ir

ed

to

rque

should

be

between

145

grams

and

160

grams

.

8.

Take

Up

Spindle

Tension

Th

e

procedure

is

identical

as

the

supply

spi

ndle,

ex

-

cept

the

r

equired

t

orque

is

between

180 g

ra

ms

and

220

gr

ams.

7

8

GE

NERA

L

TEST

PROC

E

DURES

NOTE:

Wh

enever

an

ex

te

rnal

test

instrum

e

nt

is used from

an

a

mplif

ie

r

ou

tput,

an

8 ohm resistor

sho

u

ld

be placed

acro

ss

the

amplifi

er

o

utpu

t or the

test

in

strument

input

,

if

the

use of

the

test

instrument

diseng

age

s

th

e

amplifier speakers.

II

Prea

mp out

pu

ts

are

used

for

measureme

nts

,

us

e a 270K 1W load r

es

istor.

Durin

g Record

modE'.

an

int

e

rn

al 8

or

10 o

hm

dummy

load resistor is

au

tomatica

Ti

y inserted to

re

pla

ce

the

speake

rs.

Anytime a high level signal

is

u

se

d,

the

wavPform

mo

uld be ch

ec

ked for d

jstort

ion

on

an oscilloscope.

Outpu

t:

Pla

y back

at

full

,-o

lume

and

ton

e.

a 700 cps

ton

e. recordE'd

at

0 ob.

as

meas

ur

ed

on

an

external l

abo

r

at

or

y

type

VU

Meter.

Measur

e

th

e

output

on

th

e s

am

e

type

exte

rn

al

VU

Meter

with

the

recorde

t·

termn

ate

d

into

8 ohms.

Square

the

resultant

voltage n•arung from

th

e

VU

Me

ter

an

d

di

v

id

e by 8 o

hms

to

get

th

e

RMS

power o

utput

in

watts. (P =E2/ R) .

Si

gnal

-

To-Noise

:

Pl

ay

back a 700 cps tone

pr

e-recorded

at

0 db,

as

measur0d

on

an external laboratory t

ype

VU

Meter.

Adjust

th

e

re

corder vol

um

e control

until

an

exte

rnal

VU

Meter

fr

om

the

output

reads

0 db.

Without

changing

the

record

er

volume control

sett

ing

,

stop

the

tape

motion wHh the

Pau

se

Lever

and

1·ead

the

e

xternal

VU

Meter.

The

VU

M

ete

r

is

now reading r

es

idual noise

on

ly, no signaL

Th

e reading

in

db

of

the

residual noise level

at

t

hat

vo

lume

sett

ing is

the

signal/

no

i

se

ratio

at

0 db level.

Frequency

Response

:

NOTE:

F

ir

st

cl

ean

and

demagn

etize

an

d

adjust

azimuth

of

the

heads.

Set

the

counter

io

'000' a

nd

reco

rd

a -12

db

line

input

700 cps tone

at

-1

0

db

as

measured

on

an

exter-

na

l VU

Met

er. (

If

in

put

me

ter

no

t

avai

lable,

set

record

er

volume control

1/.t

turn

open

an

d

adjust

the

os-

cilla

tor

output

, for -10

db

amplifier

out

pu

t.)

R

ec

ord

th

e 700 cps tone at - 10

db

f

or

10 digi

ts

on

the

counter,

the

n c

hang

e tones on

the

oscillator

fo

r

10

di

gi

ts

per

tone. without changing

the

oscillator

output

level

or

the record

er

volume control

se

ttin

g.

Th

e tones to

be

reco

rd

ed

after

the

700 cps reference

ton

e

are

50, 1

00

, 250, 500, 1000,

2.5K

,

5K,

7.5K,

lOX

,

12.5K,

15K

,

16K

,

and

17K

cp

s for 10

di

g

it

s each.

After recording above, rewind

th

e

tape

to th

e beg

inning

'000',

and

set

the tone control for the '

fl

at' se

tt

i

ng

for

the speed

that

is

be

in

g used.

Play

th

e 700 cps

lo

ne referen

ce

frequency

at

the

begi

nnin

g of

the

tones

an

d ad

just

the recorder vol

ume

for

an

ou

tp

ut of -

lO

db

on

an

ex

tern

al

VU

Meter.

Do

not

ch

an

ge

th

e volume or tone c

ont

ro

l

sett

in

gs

after

th

e 700 cps

-lOdb is

sd.

R

ea

d the external VU

Meter

evpry 10 digits

as

the

tone

changes from

the

50 cps

to

17K

cps

.

The v

ari

ati

on

::.

from

th

e - IOdb, 700 cps referen

ce

frequency original setting, is

the

frequency respons

e,

w

hi

ch

may

be plo

tte

d on log

paper

f

or

a curv('

o1

·

simply

by

the

numbers.

Wow

And

Flutter:

Play

back a 3000 cps

st

and

a

rd

prerecord

ed

wow

and

flutt

er

tE'st tape,

that

guarantees

a wow a

nd

flutter

wit

hin

.07%. a

nd

read

the

E'ffeclive v

alu

e on a wow a

nd

flutt

er

meter.

SPEC~

&

PROCEDURES

Hum

At

max.

volwne

-30

db

( -

40

db

at

preamp

)

At

min

. vol

um

e

-60

db

Signal-to-

Noise

Record

to

Play

-43

db

min.

Pre-recorded

-

44

db

min.

Wow

&

Flutter

.2%

max

at

7%

.3%

max

at

3%

Tone

Conlrol -

12

db

at

10KC

+13

db

at

lOKC

H

ea

d

Current

(OSC,

Fr

eq. lOCke)

Erase

12

MA

to

15

MA

Bi

as

.54

MA

to

.56

MA

Record .029

MA

to

.031

MA@

lKC

Power

consumption

at

117

V.A.C.

60

cps

55W

(1660D)

BO

W (1640-1650-1670)

Erasure

R

ecord/P

lay

at

0 db, 1000

cps

-42

db

using

1KC

filter

Fus

e: 1%A. 250V.

Gain from

sta

ndard

operating

l

eve

l pre-recorded

tape

7¥2

ips

volume full .4 vo

lts

at

preamp

minimum

<!MV

at

700

cps

head

input

= .25 vo

lts

at

preamp

minimum

2 MV

at

mike

for 0 level record

125MV

at

pbono

for 0 le

vel

record

Cros

sta

lk

Reco

rd

Ch # 1

at

0

db

, 700

cps

Play

Ch

#2

at

same

set

ting

that

Cb

# 1 is

set

at

for

.25 V

output

on

Ext.

meter

at

preamp

output

-55

db

min.

Cross

Channel

R

ejec

tion

Reco

rd

both

channels

at

0 db, 700

cps

Play

tape

and

set

both

channels

to .25 V

at

preamp

output

Re

verse

tape

and

play

-55

db

minimum

9

-

00

TAPE

DECK

PROBLEMS

j

Capstan

does

not

rotate.

Troubles

with motor

-"'

1

~,oken

field coil.

Check

field

coil

with

tester,

and

replace

motor

if

coil

IS

broken.

I

HDefective motor

starting

capacitor

Replace

I

H

Rotor

shaft

dragging due to lack

of

oiL

Overhaul

motor. Clean and re·lubncate oilite metal. \

y

Some

foreign

matter

exists

between

rotor

and

stator.

Check

and

eliminate

foreign

matter

for

free

rotation

of

rotor.

1

Troubles

with

power

transmission

r-

---1

.

Replace

belt. I

mech.anism.

Broken

capstan

dnve

belt.

---i

Capstan

drive

belt

off

of

driving position.

Place

belt

in position. I

-1

Motor

bushing

slippmg

on

motor

shaft.

Tighten

mounting

screw.

\

-i

Oil

attached

to motor bushing and/or flywheel Wipe

off

oil with

cotton

swab

soaked

in alcohol. j

r1Decreased

motor torque.

Check

motor

torque

and

replace

motor. j

I

Capstan

rotates

in

Stop

position,

but

I

tape

does

not

advance

when

switched

Troubles

With

motor.

WDefective

Replace

to

Play

pos1t10n. screw. 1

Motor

bushing slipping

on

motor

shaft.

Tighten

mounting

Troubles

with power

transmission

f-rl_

mechanism. Capstan drive

belt

stretched

Replace

belt. I

HOil

attached

to

motor

bushing

and/or

flywheel. Wipe

off

oil. I

H

Capstan

bushing

sllping on flywheel

shaft.

Tighten

capstan

mountmg screw. I

H

Excessive

tension

in

Takeup/Supply

reel

table

assembly.

Readjust

tension.

!.

rl_Oil

attached

to

capstan

and/or pmch

wheeL

Wipe

of

oil. I

Y

Insufficient

pmch

wheel

pressure.

Check and

re-adjust

pinch wheel pressu,re. I

!.Capstan

advances

tape.

but

take-up

reei-rl

Reel

shaft

dragging

due to lack

of

oil. Check take-up

reel

shaft

assembly.

1

Overhaul

reel

shaft

assembly:

relubricate.

Replace

I

does

not

take

up

tape. H

Take-up

idler

wheel

does

not

rotate

properly.

Check

idler

wheel.

Replace

if

necessary.

I

reel

shaft

assembly

If

not

repairable.

HOil

attached

to

idler

wheel and

or

ro-

ller

on

take-up

reel

shaft

assembly. Wipe

off

oil. I

Y

Take-up

idler

whee!

does

not

keep

good

contact.

Check

idler tension

spnng.

Replace

spring

if

necessary.

J

Check

lever

J

ITake-up

flinctwns

normally.

but

tape

jrl

Troubles

with motor. w

Rotor

shaft

dragging

due

to

lack

of

oil. Overhaul motor. Clean and

re-lubricate

oilite metal. J

speed

lower

than

regular

speed.

Defective

motor

starting

capacitor

Replace I

~Fluctuation

in

power supply.

Check

line voltage

and

cycle.

Use

voltage

regulator

1f

line voltage is

lower

than

standard. I

Troubles

with power

transmission

Qlpstm

drive

belt

stretched

mechanism.

and

slipping

on

motor

bushing

Replace

belt. I

Capstan

drive belt

not

in

correct

driving

position.

Place

belt

in position. J

Oil

attached

to

motor

bushing

and/or

flywheel. Wipe

off

oil. I

!wow·

flutter.

Irregular

tape

movement.

r-

---1

Troubles

with motor.

Rotor

shaft

dragging due to lack

of

oil. Overhdul motor. Clean

and

re-lubricate

oilite metal. J

W

Defective

motar

starting

capacitor

Replace I

~Troubles

with power

transmission

r--

Check

reel

shaft

assemblies.

Replace

reel

shaft

I

H

Take-up,

supply

reel

shaft

dragging

or

excessive

tension.

assembly

if

tension

not

adjustable.

mechamsm. H

Capstan

drtve belt stretched

and

slipping.

Replace

belt. ]

HUnbalanced flywheel

rotation.

Check balance. Replace flywheel. I

H Rubber on pinch wheel

deteriorated.

Replace pinch wheeL I

H

Pinch

wheel

or

tape

guide

does

not

rotate

smoothly.

Check

and

replace

defective

part.

Clean

and

re-oil I

if

it

again

provides

smooth

rotation.

H

Dust

on

heads.

Clean heads. I

H

Insufficient

pinch wheel

pressure.

Re-adjust

pinch wheel

pressure.

l

H_

Gapstan

bushing

slipping

on

flywheel

shaft.

Tighten

capstan

mounting screw. I

Y Worn-out

idler

wheel

or

no

oil.

Replace

worn-out

Idler.

Lubricate oilite

metal

in

center

of

idler.

I

IUnit

does

not

operate

in

Fast.

ForwardJ-n

Troubles

with

power

Oil

attached

to

take-up

idler

wheel

or

motor

Wipe

off

oil. J

Take-up

reel

shaft

does

not

rotate

even

without placing

recording

tape

on unit. transmission

mechanism.

bushing.

Loose

motor bushing.

Tighten

motor

bushing

moWlting

screw.

l

Take-up

idler

wheel

does

not

fllilction

properly.

Check and

readjust

idler

wheeL I

Take-

up

reel

shaft

assembly

does

not

function

Check.

clean

and re-oil

reel

shaft

J

properly.

assembly.

Check

lever

I

/Check

motor torque.

Replace

mo

-~

y_

Take-up

reel

shaft

does

not

rotate

when

recording

tape

IS

placed

on unit.

Troubles

with motor.

Decreased

motor torque.

tor

if

required.

Defective

motor

starting

capacitor

Check

and

replace

I

Troubles

with

power

.

~

Excessive

slippage

of

clutch

mate-

rial

(felt} in

take-up

reel

shaft

Check take-up

reel

shaft

assemblyj

J

transmission

mechanism. assembly.

I

Tape

guide

roller

does

not

rotate

smoothly.

Check guide roller. Re-Oil

or

replace.!

Take-reel

warped

and

sticking

to

Defective

reel.

Check

and

replace

reel.J

deck

top

panel.

I

f-~

Supply (rewind)

reel

shaft

does

not

rotate

Troubles

with power

trans-

Oil

attached

to

rewind

idler

or

mo-

Unit

does

not

rewmd tape. mission mechanism. Wipe

off

oil. l

even

without placing

recording

tape

on unit.

tor

bushing.

]Intermediate

idler(black

bakelite

Check

internal

idler. I

I

wheel}

not

working

correctly.

Loose

motor

bushing

.

Tighten

motor

bushing

mounting

screw.

l

. jRewind

idler

does

not

rotate

or

not

Check rewind idler. Clean and re·Oil-l

Jin

position.

~upply

reel

shaft

assembly

does

no

Check

supply

reel

shaft

assembly. I

~tate

smoothly. Clean and re-oil

y

Supply

(rewind}

reel

shaft

does

not

rotate

rrlTroubles

with motor. ]Check motor torque.

Replace

motor I

Decreased

motor

torque

when

tape

is

placed

on unit. lif

not

repairable.

Defective

motor

starting

capacitor

Replece I

Excessive

slippage

of

clutch

mate-

~Trouble

with power

trans-

Check

supply

reel

shaft

assembly. I

mission mechanism.

rial

(felt)

in

supply

reel

shaft

assembly.

Loose

tape

winding

after

being

placed

in

Rewind

or

Fastforward

mode.

Tape

spills

when

stopped

from

Rewind

or

Fast

forward

mode.

Break

does

not

functwn

properly.

PenodJcal

clack

noise when

rewmdmg

or

fast

forwardmg tape.

Loud motor VIbration.

Y

Defective

reel.

Decreased

back

tenswn

of

take-up and supply

reel

shaft

assemblles.

Excessive

sllppage

of

felt

clutch

matenal

m take-up and

rewmd

reel

shaft

assemblles.

Reels

of

different

s1ze

are

used.

For

example. 5·

reel

on

take-up s1de and

7~

reel

on

supply Side.

Worn-out

brake

shoes.

Oil

attached

to

surface

of brake

shoes.

Loose

brake

shoes.

Brake

lever

does

not

function properly.

Worn-out and

ragged

Idler wheeL

Loose

motor mountmg screw.

Defective

motor

starting

capacitor

Tape

gmde

roller

does

not

rotate.

Check guide roller. Re-oil

or

replace.

_j

!supply (rewind)

reel

warped and

stick-

Check and

replace

reel. l

ling to

deck

top panel.

Disassemble

reel

shaft

assemblies

and

strengthen

back

tension.

Readjust

slippage

of

felt

clutch

matenal.

Replace

defective

reel

shaft

assembly

if

this

readjustment

IS

difficult.

Always

use

reels

of same

size

on

both Sides.

Check and

replace

brake

shoes.

Check

and

re-adjust

brake

lever.

Replace

idler

wheel.

Roberts 1640 Bedienungsanleitung

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