Roberts 1660D SERVICE MANUAL

SERVICE

MANUAL

1B40-1B50-1BBDD-1B70

TAPE

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RECORDERS

·

IMJ

$2.50

IDENTIFICATION

CHART

MODELS

!KEYED

1.

2.

3.

4.

5.

6.

7. I

8.

9. Ta

I 0. Tok e-

I I .
1 2.

13. Pi

14.

15

.

16.

17. l e

18. Right

19. le

20. left C

21.

22

. Right

23. Right

24. Left

25. Right Ch

26.

27

. Power Switch

28

. Record I

29

. Power

30

. St

31. Right Hum Adjustment

32. left

33. Right

34. lC!

35

.

36. lei
37

. Ri

38.
39

. Right Channel Tweeter

4

0.

4 1. Righi

4 2. l

43.

44

. l

1640,

TO

Supp

ly Reel

Suppl

y Reel

l e

ft

Channel

(Not

Tope

Guide

Automatic Shut-

Drive

Cop1tan Stora

ndex

Editing

ke-up Reel Hold

up

((ronne

Right

(Not

Drive

Capst

nch Wheel

Pau>e

R

ewi~d

Stop

/ Stor l Con1ro

ft

Channel

Channel

ft

Channel

hann

(Oual
Modl!l 1640
Model.

Speqkcr

Mod

el

Switch

Channe

(N

ot

Channel Volume

Channe

Ton

e Control

ereo Headphone Jock ( 1650 & 16

Hum

Cho M cl Preornp Output ( 164

ft

Chonnel

Right

Channe

I C

hann

ghi

Channel

Left

Channel Speaker Output ( 1640,

Loll Chann

Cho nnol

ei I Cllonnol High

Ri

ghi

Channel

ell Chonn

1650, 16600, 1670.

ILLUSTRATION AT RIGHT!

Hol

der

Spco~cr

in

1660D. Out

Roller

Off lever

Count

Guide

Reel

in

leve

r

/

Fasl Fo

el VU

Purpose Met

1650 and 1

1660D:

in Mod

annel Ploy/

ndicator ligh

Cord

Adjustmen

el

el TwDet

al l

ge

er

er

l S

peak

1660D. Outboard

an

rwar

d Co

l

Miaophonc

Microphone Inpu

Volume Con

Meter

: left/ Rig

670

Switch

R/ l - NOI'I!IOI • l / R

l VU

Meter

el 1640

l Play/ Record Switch

Record Switch

Conn

ectio

t

Pr,omp

l Phono/ Rodio

Phon of Radio Input

Speaker

cr Out

High

Levol Out

Level Outp

Low Level

ow

l evel Outp

board

In

Post

er

in 1670)

ntro

l

Inpu

t,

t

trol

er

on

Madel

hi

VU Me

ier Swit

: M o

nilor-Normai·Mul

)

Control

t

n

Outpu

t (

164

Inp

ut

Output

(I

Oulpul ( 1650,

put

(16

put

ut (

Output

ut (

1670)

1640)
ch

Channel Tr

70

J

0,

1650, 1670

0,

1650

640.

1650,

1650, 1670)

1670)

50, 1670)

II660D onl

1660D onl

( 1

660

0 onl

1660D

onl

, 1

y)

e

ansfer

670)

1670)

y)

y)

y)

Ll

V)-

--"'~---,

{ll)

l--

--

-

-=-==='-'

I

Power

Moving

power

to

power

is

Switch:

Lhe

the

motor

cut

off

to

power

and

the

switch

amplifier.

entire

to

the ·'ON" posilion

In

the "OFF

unit

.

FUNCTIONS

applies

" position,

OF

CONTROLS

stop

mode, the

to pr

event

excessive
forward
modes.

oper

ations.

lifter

This

pushes
wear during

also

the

mules

tape

the

away

fast

the

from

rewind

~ound

during

the heads

and

fru;t

these

Volume:

A

separate

The

volume

record

level

Tone:

The

sponse

VU

when
sho

Record

switch

record

of both amplifiers.

record.

Meters:

The

recording,

uld

be

Switches

To

operate,

t

urn

the

in

When

switch

Channel

This

nel

over

or

radio/ phono

ing

channel

The

hann

els

c

Tape

Lifter:

The

by

the

stop/start

volume

control

when

making

tone

control

VU

Meters

and

to

between - 3

:

depress

stop/start

record

the

Transfer

switd1

to

the

during

process

to

make a multiple

tape

conh·ol to

mode

stop/start

automatically

Switch:

inte

rnally transfers
input
addition

recording.

may

lifter

is

control.

control is

varies

a recording.

setting

Tone

are

used to

balance

and

either

.

control

(1660-D)

of

the

is

be r

epeated

under

When

provided

the

playback

determines

controls do nut. work

monitor

stereo

-7

for

or

both

"start.

is re tu

snaps

other

added

recording.

the

head

the

the

play.

best

recording

record

..

This

rned

back to

the

output
channel. A microphone
to

the

back

and

cover

stop/start

for

each

vol

ume,

[re

the

Meter

switches,

holds

to "

play

of

transfer

forth

and

control

channel.
and

guency re-

during

record

level

indication

results.

then

the

record

stop," the

mode_

one

chan-

receiv-

between

is

operated

is in

the

Stop-Start:

Starts

tape

Stops

tape movement

Rewind-Fast

Fast Forwa

up

reel

at a fast

tape

onto

the

Pause

capstan,
dle.

the

tmned

Index

reel

Hum

openings,
justing
Without
just

Auto-Stop

circui t is
runs
breaking

Lever:

In

t.he

"Up

and

Tape

stops

record

level

to

"Down"

Counter:

Pr

ovides a

of

tape

without

Adjustment

On

Lhe l'ear

these

Potentiometers.

tape

the

cont

Switch:

When

tape

completed

out,

is

the

movement

Forward:

rd

position

rate

feed

reel

' posilion,

take-up

tor

instantly.

without

position,

means

skipping

Controls:

paneL

are

the

on

the

unit,

rols for

of

circuit,

minimum

holds

and

insufficient

shutting

i11

"Play'

when

moved

advances

of speed. Rewi

at a fast

of

next

They

the

pinch

que

This

tape

locating

and hun

to

Right

turn

aut

the

motor
tension,
off

rate

roller

is r

emoved

permits

movement.

the tape

lhe

and

are

screw

the

hum

o-stop

the

' or
lo

the

U1e

nd

of

speed

is moved

movement

desired

ting

A.C.

Left

volume

on

switch

runs.

the

motor.

"Record"

"Stop''

tape onto

position wi

.

away

from

take-up

an

adjustm

\Vhen

lever

select

.

Receptacle

Channel

driver

adjustment.>.

up

full

each chann

''U

p," the

If

the

tape brea

switch

lever fa ils,

position.
position.

the

nds

ent

is re-

begins.

ions

are

hum

and ad­el.

motor

take-

the

from
spin-

on

two

ad-

ks,

of

a

Microphones

A
These
of

the

Note:

Phono-Radio

Each

for

making

tuner. These

microph

input

left

channel

channel

:

jacks

When
crophone
crophone

Input:

direct

inputs

o11e

input

are located on

volume

using

the Phone-Radio
plugs
jacks.

is

provided

recordin

are

located

is

provided

control.

must

gs

from

for

each

the

front

panel

inputs,

be removed from

with a Phono

a radio.

on

the

phonograph,

rear

IN

PUT

to

-Raclio

panel.

AND

channel.

the

left

the

mi-

the

mi-

input

or

OUTPUT

JACKS

Outputs:

1660D .
outputs.
puts
an
on

type

level

Te5ts will show

ode
c.:ables

1640 ... On

and

1650 & 1670 . . . Has
two
the

..

each

are

used

external

the

rear

The

high

amplifiers

inputs.

The

low level

The

high

follower

without line

two

high

phono

internal

There

panel.

type

are

two

adjustable

to collllect

power

amplifier.

level

that

outputs

which

and low level

outputs

losses.

the

rear

impedance preamp

jacks

speakers.

high

by

the

the

outputs

have

tu_ner,

are

is

best

outputs

allowing for

(Janel

are

the

same

for

extension

There

and

two low level

volume

1·ecorcler

The

are

for

outputs.

is

also a stereophone

cont

playback

output

used

with

auxiliary or

for solid

each

individual

are

low

lvnger

two

external

outputs

speakers

rols.

jacks

state

impedance

as

preamp

These

out-

system

are

standard

othe

amplifiers

interconnecting

speaker

the

1640,

to

work

to

located

tube

r high

case.

cath-

jacks

plus

with

jack.

.

3

Fig.

PARTS

2.

Top

IDENTIFICATION

View

of

Tape

Transport.

Hook-Up

1. T

low
The instructions

t
following

I
Hi

Low

Rad/Ph

to

..

Procedures:

he

outputs,

impedance

un

er

should

may

nterconnecl ... .

gh

l-ev

el

·

Level

Output

ono Input

to . . P hono.

to

.. Phono. Prea

to

..

parall

parallel

(1660-D)

high

and

preamp

of

the

be

followed.

be

helpful.

Output ... to

...

to

...

to

to

..

Amplifier Tape Out

to

..

Amplifier Preamp

Ceramic

mp

el w

ith

TV

with Radio

low level are

outputs.

external power

However

..

Tube
a. High

b.

Auxillary

c.

Preamp

d.

Tuner

..

Transis

..

Tuner

spe

speakers

a.

b.

c.

d.

Out

aker

tor

Input

Preamp

Tuner

Auxiliary

Output

Cartridge

s

cathode

as a rou

amplifier

level input

input

input

amplifier.

input

input

Out

OPERATING

follower.

amplifier

.

input

input

gh

and

guide

INSTRUCTIONS

Threading

1.

Place
re

el

or

the

on t.ak

reel

holders

Unwind

2.
section
!.ape

pulls

p

o.>

ition.

3. T

nsPrt

of

takeup

seve

ral

To

Make a Stereo

1.

Connect
with

power cord provided.

On.''

2.

Thread

3. Co

nn

ect

a.

If

microphones are

jacks. L evel will

the

Tape:

a full

reel

eup

provided.

aboul

of

tap!'

automatic

fre~t

end

reel. Ho

turns coun

reco

the

t.ape.

signal

of

tape

on

feed

spindle. Place

spindle.

14

taut

of

Secure

inches

and

tape

tape

into

ld

tape

terclockwise to

reels

of

tape

thread per photo. Make

shutoff

one

end

in

place

from

feed r

switch

arm

of the radial

in

place

secure

tape

Recording:

rder

to 110-125 volt 60 cycle power sour

Tur

Set

source

be

Index

to

proper
used
contro

n power s

Counter

input.

connect

lled

to

them

by

the volum

witch

zero.

an

with

ed.

u p

to

slots

and

turn reel

to

the

to "Po

to

microphone

e c

empty
rubber

H"old a

sure

"On

in

hub

reel.

wer

ontrols

"

ce

.

4

b.

If

a

phono
puts
jacks. Level will

4.

Push

Pause

!i.

Hold

record switches depressed.

Tum

6.

7.

8.

9.

10. To

To

1. Co

2.

3.

start/ stop control

the

record

Start

signal sour

should

read

Release

1

and 3 are

When

recor

of

reel

·

'Stop''

leased

record

spindle.

as

in

steps

position.

to return

Play a Stereo

nnect

cord

provided.
Thread
Locate

Rewind knob

desir

or

radio

to

the

respective

be

controlled

Lever

to

"Up"

switches down

ce to

-3

to - 7 on

the

Pause

Lever

now being recorded.

ding

is

completed,

tape

is

reached,

Record

to

play

tracks 2 and

turn

over

and place

2 - 9.

Recording:

recorder

the

Turn
tape.
ed

while

to

proper

power

Set

starting

observing

Ind

Fig.

3.

source

is

used

connect

channel

position.

to "

Start" pos

in

record

set

recording

the

average

(down)

return

switches

position.

4, remove full reel from

on

switch

ex

Counter

point

by

or

supply

power

by

Index

Phono-Radio

the

volume

it1

on.

mode.

level.

.

to

start

when

the

start/stop

are

automaticaUy

spindle.

sour

ce

to

"Power

to ze ro.

using

Fast

Counter.

This

Bottom

their

controls.

hold;;

VU

Meters

tape.

end

control

take-up

Proceed

with

On."

Forward-

View

out-

input

Tracks

of

the

to

re-

power

of

Tape

Transport.

4.

Turn

Start-Stop

for

each

channel.

tracks 1 and 3 of a 4-track

5.

Tape

may

be

advanced

Stop

knob

is

placed

Forward-Rewind

To

play

6.
tracks 1 and 3 have
Remove
place

Monaural

Proceed

jacks.

trols for

To
recording
Lakeup

spind

4.

Reverse
Rever.se
order

To

of

tape

tracks 2 and

full ree\ from takeup

on

feed spindle.

Recording

as

indicated

contro

ls

and

the

unused channel

record four

track

1.

spindle,

le.

Continue

tape

to record

play

sides

tape

again

back

and

turning

and

track

four

knob to "

Both

tracks

in ··stop

knob.

4 of a 4

been

Proceed

and

Play

for

switches for

monaural

Reverse

it

over.

to

use

left channel

use

right

and

continue

2.

monaural

recorder

Start"

position.

of a 2-track

stereo

tape

rapidly

tape

channels

or rewound,

" position,

-track

stereo

completed, do

spindle,

as

in

bac

k:

stereo

operation

one

channel.

should

be

tracks.

use

by

removing full r

and

placing

while

channel to

to

tracks.

use

as

Adjust

ste

reo

will

now

be

after

by

using Fast

recording

not

rewind

turn

it

over.

Steps

2-5 above.

but

use

Volume

set

at zero.

left

channel fir

eel

it

on

the
recording
record

use

right

the

when recording.

channel

same

track

sequence

volume

tape

or

played.

Start-

after
tape.

and

only

con

st.

from

feed

track

3.
in

-

5

SOUND-WITH-SOUND

This

is a

used

procedure

in

suc

for

language

as

often

h a

tne

cording
be
corded
de

aler, have

RECORDING

by

manner

study.

as

desired)

instru

cor's

PROCEDURE:

1.

Make a master
low

procedure

2.

Rew

ind

tape

3.

Record

4.

Rewind

5.

Play
heard

6.

Track 3 may

on

t.ape.

back recording,

on

the Right chann

recording on

m1der "

.

Track

be

3,

erased

whi

ch

you

as

To

using Right ch

as

may

to

make

with

the

on the o

voice

pre-recorded

Trac

Make a Stereo

in

stereo

el.

and rerecorded

record

the

teacher

ther

k 1.

ann

play. Master

yam favorite

playback

's

voice on one

channel.

in

using

Recording

el

only

without dis

sound

ROBERTS

this

manner

Left

chrumel

while

recordin

turbing

orchest

as though

channel

,"

using Left

listening

g will

ra

on one

you

and

Langua

in fo

only. Turn

master track

ur

to

be

ge

differe.

channe

Track

heard

channel,

were "right

your respo

Laboratory Tapes.

nt

language

Right

l only.

1.

on Left

by

and

there

nses which

s.

channel

channel

repeating

then

play

..

with

available from

volun1e

and

Steps 2 through

or

the

orchestra. Or

may

be

controls

added

sing

erased

your

to zero

reco

rding

4.

with the

it

and

Robe

and

will

re-

ma

re-re

rts

fol·

be

y

SOUND-ON-SOUND

1.

Make

original

procedure

2.

Re

wind

tape

3.

Set

Channel

4.

Pu

sh Pause

5. H

old Rig

6.

Connect

proximately

7.

DO
ROPHONE

8.

R

elea~e

9.

Adjust

nel

the Right

10.

Rewind
peating St

11.

Play
sho
Step

12.

The
tirl
microphone

Right

N0'1'

Pau

the Left

VU

Meter

the

back

uld

be

s 2

through 9 may

abo\·e process may

e reco

RECORDING

recor

unde

Tran

Lever

hi

Reco

READJUST

RECORDING

:e Lever

channel

eps 2 !hrcu

rec

set

rdin

input

ding

r, ''T o

to beginning

sfer

up

rd

challllel

half

the

channel

should

micr

tape.

play

ording. So

to zero. (NOTE:

g.

In

this

will

Switch

(1660D

on

Track 1 usi

Make a Stereo

of

original

Switch

io

to "Stop

normal reco

and

gh

'' position.

depressed

microphone. Apply sig11

THE

LEVEL.

make a

volume

be

read

opho

be used.

ing

ne.

the

trial

9.

und-On-Sound reco

be

repeated

be

repeated,

case

the

ONLY)

Recording."

recording.

"L toR" position.

and

rding

RIGHT

(V:!

tdal

recording

cont

rol only, while

full

normal. Half

recordin

The

original
if

using

Channel

ng Left

level reading
CHANNEL VOL

the

channel

turn

Start-St

al

to

microphone

•Jormal)
of

the

watching

of

g.

If

the

test

rdin

g is on

Track l recording

final recor

Tra

ck 3

Transfer

Switch

only.

o p knob

on

the

UME CONT

Lef

t

the

reading

run

Tra

ck 3 (

ding

as

the

Turn

Right

to "Start''

and adjust

Right channel

cba~el

the Right

will

was

satisfacto

Right

of

was

original reco

should

the Left

not satisfactory

be set

ASSEMBLY -DISASSEMBLY

channel

posi

VU

ROL

trSllSfer

channel

be

the Left

ry.

channel

rding

at

volume

tion

.

the Right

Meter.

AFTER

and

the Right

VU

cbrumel transfer

proceed

) so volume

amplifier

.)

and

add

"R to L" position,

cont

channel

PRESETTING

channel

Meter

with

the

is

still

more mate

rol to ze

volume c

readin

final

controls

intact

rial

and

ro

ontrol fo

FOR

THE

microphone

g. The

ru1d

the

recording

for

at

this

to

the Left

Righ

Left

it

and

follow

r ap-

MIC-

added

t chan-

other

half.

by

re-

cha

nnel

point,

for a rnul-

channel

.

so

Assembly

1. Check for

2.

3.

4. R

5.

6.

6

(mounting):

eration.
panel.

Rem

In

sta

einst

up

against

If

panel

underside wit

If

panel

nuts

etc.).

C

ut

ove

side

ll unit

all side

is

clear

dearance,
out

underside

is

.1f2"

less than

through

(1660-D)

(deck & prean1ps, reels,

Transfer

panel

open

angle

bra::k

into

panel

cutout.

angle

brackets

of

or

mar~

h wood screws,

1

/2"

panel.

cutout

ing.

ets

{rom

panel.

thick,

thick

onto

fasten

into

use

pattern

metal

panel.

from

cage.

rne.tal c

age, and

angle

brackets

fancy headed

ease

of

template

press

bolts

op-

to

from

and

For

l.

Remove

2.

Remove
ing

3.

Pr
screw.

4.

Remove
screws.

as they

5.

Lift

Access

to

Start-Stop

3 tr

storage rost

y o

ut

pinc:hwheel

and

bc>th
Note hum
are

off

transport

Top

ansport

.

lift

oU

reel tables

removed.

of

Tape

Deck:

Jmob and Fast Forw

deck

mounting

cap.

take o

ut

pinchwheel.

after

ber

deck

of fibre

panel.

spacers

ard-Rewind kn

screws, capsta

pinchwheel

taking CJut reel

und

mounting

er

reel t ables

ob.

n bush-

table

L

ubricate

the

<eco
under
of

l.

2.

rder

mod

occasiona1 use.

Feed

and

machine

Rewind
dr

ops

of

the

following

is

subjected

erate

usage,

take-up

oil

on

each

idler

bearing

Light mach

parts

to

heavy

and

once a

spindle shaf

shaft.

and

oil

on

wind

each

ine

every

usage.

ts

with

idler

bearing

th<ee

every

yea

r unde<

two

bearing. with

.

MAINTENANCE

INSTRUCTIONS

LUBRICATION

months

drops

when

six

months

conditions

of

light

two

CLEANING

3.

Apply a liberal

on

all

levers

4.

Sa

tuTate

drive

capstan

Caution:
the

ing

drive

the

Do

surf

tape.

the

not

ace

and

with

s,

amount

cams

felt

allow

or

of

.

washer in

light

machine

grease

on

plastic surfac

light

or

grease

the ret

oil.

oil

to

es

to

each

roller

aining cup

remain

or

any

on

part

and

of

the

any

touch-

of

The

head

1.

the
pole
tigh

on
up
until

2.

as the

3.

scre
surface

4.

shaft
The
50 gr

capstan,

and

Record-Play

Height-L

.he

ad

mounting

piece

ten the

Azimuth

the

recorde.r.

per

and

position

Erase

Head

The

erase bead

Rec

ord

Brake

Shoes

When brake

ws a

nd

is exposed

Rewind

To

bring

adjust
pressure on
ams

during the rewind

erase

head

Head

oosen

is

even

nuts.

-Pla

loosen lo

of

maximum

-Play head.

rotate

Idler

Wheel

the

both

the

pinchwbeel,

accumulate a tape

the

two

mounting

bra

cket.

Move

with

the

top

ce a

prerecorded

While

shoes

the

wheel

the

playing

wer

head mou

output

height is

shoes

to

the

idler

knurled

adjusted

become worn, loosen

a few

supply

in

alignment

load

motor

operation.

tape

edge

is

degrees

and

spring

guides,

the

azimuth

tape

nting

found.

bushing

and

oxide

nuts

at

head

so

of

the

alignment

alternately tighten

nuts

in

the

same

the

until a new

take-

up

with

the

and

the

rewind

shou

.reco.rd/

MECHANICAL

that

tape.

or vi ce

reel

coating

the

side

the

Gently

manner

mounting

discs.

rewind

ld

be

play

as

ADJUSTMENTS

of

top

tape

versa

brake

reel

roller.

about

the tape
with a soft

sure

unit

6.

50 g

idler

assembly. Make

7.

another

which

which

ard
hub
twenty
of
Position
zontal
be

passes

cotton

shou

ld

is

operating

Rewind

Adjust

rams of

wheel

Supply

the

between

A c

han
metal

increases

has

The req
seven

diameter

six

leader

the

axis.

Spindle

the

inch reel

feet

be

Intermediary

the

pressure

and

ge in torqu

uired

t.ape to a scale

scale

Exert a steady pulL

145

these

parts.

swab

dipped

between
at

7%

1,000

ips.

Idler

intermediate

equally

the

rubber

adju

stment

Tension

e is

washer

reverse effect..

on

tension,

tensi

the

of

leade.r

vertically

grams

next

or

on

is

with a two

supply

tape

and

160

Clean

these

in alcohol.

and

1,150

wheel spring

exerted

ring

in

the rew

accomplished

to

the

by

See

determined

spindle.

wound

with a range

with

The required torque

grams

to

on

the

ind

one

in

removing

explo

ded view

and

one

The reel

on

respect

.

parts periodically

grams

supply

by

the

by

fourth

it.

of 0 to

to

obtain

both

mode.

either

clutch

the

existing

placing

Attach

to

the reel

when the

the

rewind

reel

adding

assembly

for

location.

a s

(21,.4)

should

the

250 g

should

about

shaft

tand-

rams.

one

inch

have

end

hori-

5.

Pinch

Wheel

To

bring

the

adjust the pinch

wheel
w.heel

in

ali

gnme

load spr

nt with t

ing.

The

he

pinch

capstan

wheel pres-

shaft

8.

Take

Up

Spindle

The procedure

cept

the required torque

gr

ams.

Tension

is

identical

is

as

the

between

supply

180 grams

spi

ndle, ex-

and

220

7

GE

NERAL TEST

PROCEDURES

NOTE:

Outpu

type

in

Si

gnal-To-Noise

Wh

enever

acro

amplifier speakers.

the

Anytime a high level signal

ss

the

II

Prea

Durin

speake

an exte

g Record
rs.

rnal

amplifi

er outpu

mp outputs

t:

Pla

y back

VU

Measure the output

Square

watts. ( P = E

Meter.

the

at

full

resultant

2

/ R ) .

,-o

lume

on the same

volta ge n•arung from the

:

Pl

ay

back a 700 cps tone pre-recorded

Adjust the recorder volume control

test

modE'.

and

instrument

t or the

are

used

an

intern

is use

d,

ton

e.

a 700 cps

type

until

is used from

test instrument

for

measureme

al 8

or

10 o

the

wavPform mould be checked for d

ton

external

at

0 db,
an

exte

VU
VU

as

an amplifier output,

input

,

if

nts, us

e a 270K 1 W load resistor.

hm

dummy

e. recordE'd

Meter
Me

ter and divide by 8 o

measur0d

rnal

VU

load resistor is automaticaTiy inserted to repla

at

with

the

on

an external laboratory t

Meter from

the

0 ob.

use of

as

recorde

the

an

8 ohm resistor

the

test

jstort

ion

measured

t·

termn

hms

to

output

instrument

on

an oscilloscope.

on

an

ated into

get the

ype

reads

0 db.

should

diseng

external l

8 ohms.

RMS

power o

VU

Meter.

be placed

ages th

ce

aboratory

utput

e

Without

e

xternal

Th

Frequency

NOTE: Fir

ec

R

digits

per

Th

12.5K,
After recording above, rewind

the speed

Play the 700 cps lone referen

output of -

- lOdb is

Read the external VU
The v

which

may

changing

VU

Meter.

e reading

Response

st clean

Set

the

na

l VU

tor

cilla

ord the 700 cps tone at - 10

e tones to

15K

output

tone. without changing

,

16K, and

that

is bein

lO

db

sd.

ari

ati

on

be plo

the

The

in

db

of

:

and

counter

Met

er. (

, for - 10

be

recorded

17K

g used.

on

an extern

::.

from the - IOdb, 700 cps referen

tte

d on log

record

er

VU

the

residual noise leve l

demagn

io

'000' a

If

in

cp

Meter

volume control

M

eter is

etize and

nd

reco

put meter not

db

amplifier
db for

the

after

the

s for 10 digits each.

the tape

ce

frequency

al

VU

Meter.

evpry 10 digits

paper for

sett

now reading residual noise only, no signaL

at that volume

adjust

rd

a - 12

avai

output.)

10 digi

oscillator

700 cps reference

to th

at

Do

a curv(' o1·

ing, stop

azimuth

db

line

lable,

set

ts

on

output

e beg

inning

the

begi

not chan

as

the

ce

simply

the

level

tone

the

tape

motion wHh the

sett

ing is

the

signal/noi

of

the

heads.

input

700 cps tone

record

er

volume control

counter,

or

tone are

'000',

nnin

g of

ge the volume or tone c

changes from

frequency origina l setting, is

by

the

the

the record

50, 100, 250, 500, 1000,

and

set

the

tones and ad

numbers.

at -10

n c

hang

er

volume control settin

the tone control for the 'flat' setti

the

50 cps

Pau

se

ratio

db

as

1/.t

turn

e tones on

just

the recorder vol

ontrol

settings

to

17K

the

se

Lever

and

at

0 db level.

measured

open and

the

2.5K, 5K,

frequency respons

on

adjust

oscillator for

g.

7.5K,

ume

after the 700 cps

cps

.

1·ead

an

exter-

the

lOX

ng

for

the

os-

10

,

for

an

e,

8

Wow

And

Play

.07%. a

Flutter:

back a 3000 cps standard

nd

read

the

E'ffeclive v

prerecord

alu

e on a wow a

ed

nd

wow

flutt

and

er

flutt

meter.

er

tE'st tape,

that

guarantees

a wow a

nd

flutter

wit

hin

Hum

At

At

max.
min

volwne

. volume

-30

-60

db

db

( -

40

db

at

preamp

SPEC~

)

&

PROCEDURES

Signal-to-

Wow & Flutter

Tone

Head

Power

Erasure Record/P

Noise

Pre-recorded -44

Conlrol -

Current

Erase

Bi
Record .029

12

as

.54

consumption

- 42

db

Record

+ 13

(OSC, Freq. lOCke)

MA

.2%
.3%

12

db
db

MA
MA

at

lay

using

to

Play

db

max

at

max

at

at

10KC

at

lOKC

to

15

to

.56

to

.031

117

at

0 db, 1000

1KC

-43

min.

7%
3%

MA
MA

MA@

V.A.C.

filter

lKC

60

cps

db

min.

cps

55W

(1660D)

BO

W (1640-1650-1670 )

Fus

e: 1 % A. 250V.

Gain from

7¥2

ips

<!MV

at

700

2 M V

at

mike

125MV

Cros

Cross

at

sta

lk

R eco

Play

Channel Rejec
Reco
Play

Re

verse

sta

ndard

volume full .4 vo

cps

for 0 level record

pbono

rd

Ch # 1

Ch

#2

rd

both

tape

tape

operating leve

head

for 0 le

at 0 db

at

same

tion

channels

and

set

and

input

vel

, 700

set

at

both

play

lts

= .25 vo

record

cps

ting

that

0 db, 700

channels

-55

db

l pre-recorded

at

preamp

lts

Cb

cps

to .25 V

minimum

at

preamp

# 1 is

minimum

set

at

preamp

tape

minimum

at

for

.25 V

output

output

on

Ext.

meter

at

preamp

output

-55

db

min.

9

00

-

j

Capstan

I

Capstan
tape

does

to

Play

!.Capstan

does

not

I Take-up

speed

!wow·

flutter.

I Unit

does

I

Unit

Loose
placed

mode.

Tape

Rewind

Break

PenodJcal
rewmdmg

Loud motor

pos1t10n.

advances

lower

does

tape

in

spills

or

does

does

not

rotates

not

advance

take

up

flinctwns

than

Irregular

not

operate

not

rewmd tape.

winding

Rewind

when

Fast

forward

not

clack

or

fast

VIbration.

rotate.

in

Stop

position,

when

switched

but

take-up

tape.

tape.

normally.

but

regular

speed.

tape

movement.

in

Fast.

f-~

y

after

being

or

Fastforward

stopped

from

mode.

functwn

properly.

noise when

forwardmg tape.

but

reei-rl

H

H Oil

Y

tape

jrl

~Fluctuation

r-

---1

~Troubles

ForwardJ-n

y_

Supply (rewind)

even

without placing

Supply

(rewind}

when

tape

Decreased
assemblles.

Excessive
rewmd

Reels
take-up s1de and

Worn-out

Oil

Loose

Brake

Worn-out and

Loose

Defective

Troubles

with motor

Troubles

with

With

with power

shaft

dragging

idler

take-up

idler

with motor.

with power

with motor.

with

reel

reel

tape

shaft

recording

shaft

on unit.

back

sllppage

shaft

different

brake

to

shoes.

does

ragged

motor

power

motor.

wheel

to

whee!

in

power supply.

power

shaft

shaft

IS

does

does

tenswn

assemblles.

s1ze

7~

shoes.

surface

not

starting

mech.anism.

Troubles

Troubles

mechanism.

Reel

Take-up

attached

ller

on

Take-up

Troubles

Troubles
mechanism.

Troubles

mechamsm.

Take-up
without placing

Take-up

recording

reel

reel

is

placed

reel

of

attached

brake

lever

motor mountmg screw.

transmission

transmission

due to lack

does

not

rotate

idler

wheel and

reel

shaft

assembly.

does

not

keep

good

transmission

transmission

does

not

recording

of

reel

rotate

tape

does

not

placed

on unit.

not

rotate

tape

on unit.

not

rotate

of

take-up and supply

felt

clutch

are

used.

on

supply Side.

of brake

function properly.

Idler wheeL

capacitor

TAPE

-"'

H Defective motor

H

y

r-

---1

---i

-1

-i

r1Decreased

WDefective

f-rl_

H

H
H

rl_Oil

Y

of

oil.

properly.

or

ro-

contact.

w

W

r--

H

H

H Unbalanced flywheel

H
H

H
H

H_

Y

even

on unit.

rotate

when

Troubles
mission mechanism.

rrlTroubles

~Trouble

mission mechanism.

Y

Defective

matenal

m take-up and

For

example. 5·

shoes.

DECK

PROBLEMS

~,oken

field coil.

1

starting

Rotor

shaft

dragging due to lack

Some

foreign

matter

exists

Broken

capstan

dnve

Capstan

drive

belt

off

Motor

bushing

slippmg

Oil

attached

to motor bushing and/or flywheel

motor torque.

Motor

bushing slipping

Capstan drive

Oil

attached

Capstan

Excessive

attached

Insufficient

Check take-up

Check

Wipe

Check

Check

Rotor

Defective

Check

Qlpstm

Capstan

Oil

attached

Rotor

Defective

Take-up,

Capstan

Rubber on pinch wheel

Pinch

Dust

Insufficient

Gapstan

Worn-out

Troubles
transmission

Troubles

I

Troubles

J

transmission

belt

to

motor

bushing

sllping on flywheel

tension

in

Takeup/Supply

to

capstan

pmch

reel

idler

wheel.

off

oil. I

idler tension

line voltage

drive

shaft

wheel

on

spnng.

lever

J

shaft

dragging

motor

starting

and

belt

stretched

drive belt

not

to

motor

dragging due to lack

motar

starting

supply

reel

shaft

drtve belt stretched

or

tape

guide

heads.

pinch

bushing

slipping

idler

wheel

with

power

mechanism.

with motor.

with

power

mechanism.

cycle.

in

I

Defective

reel.

with power

reel

reel

with power

with motor.

shaft

reel.

on

trans-

trans-

Disassemble

Readjust
Replace
readjustment

Always

Check

Check

Replace

between

.

belt.

of

driving position.

on

motor

on

stretched

bushing

and/or pmch

wheel

pressure.

shaft

assembly.

Replace

Replace

due

capacitor

Use

and

correct

bushing

capacitor

dragging

rotation.

deteriorated.

does

wheel

pressure.

on

flywheel

or

no

.

~

.

slippage

defective

use

and

and

idler

capacitor

of

oiL

rotor

and

stator.

shaft.

motor

shaft.

and/or

flywheel.

shaft.

reel

table

assembly.

wheeL

if

necessary.

spring

if

necessary.

to

lack

of

voltage

regulator

slipping

on

motor

driving

position.

and/or

flywheel.

of

or

excessive

and

slipping.

not

rotate

smoothly.

shaft.

oil.

Oil

attached

bushing.

Loose

motor bushing.

Take-up

idler

Take-

up

reel

properly.

lever

Check
Decreased

Defective

Excessive

rial

(felt} in

assembly.
Tape

guide

Take-reel

deck

top

Oil

attached

tor

bushing.

]Intermediate

not

I

wheel}

Loose

motor

jRewind

idler

Jin

position.

~upply

reel

~tate

smoothly.

Decreased

Defective

motor

Excessive

rial

(felt)

in

Tape

gmde

!supply (rewind)

deck

ling to

reel

shaft

of

felt

reel

IS

difficult.

reels

of same

replace

brake

re-adjust

brake

wheel.

I

oil.

1f

line voltage is

bushing

oil.

tension.

to

take-up

wheel

does

shaft

assembly

motor torque.

motor

slippage

take-up

roller

does

warped

panel.

to

rewind

idler(black

working

bushing

does

shaft

assembly

motor

torque

starting

slippage

supply

roller

does

reel

top panel.

assemblies

clutch

shaft

assembly

size

shoes.

lever.

Check

field

coil

with

Replace

Overhaul

Check

Replace

Place

Tighten

Wipe

Check

Replace

Tighten

Replace

Wipe

Tighten

Readjust

Wipe

Check and

Overhaul

reel

1

J

Overhaul motor. Clean and

Replace

Replace

Place

Wipe

Overhdul motor. Clean

Replace

Check

assembly

Replace

Check balance. Replace

Replace pinch wheeL I

Check

if

it

Clean heads. I

Re-adjust

Tighten

Replace

idler

wheel

not

fllilction

does

and

belt

off

off

of

shaft

belt

off

again

not

belt. I

mounting

motor

mounting

belt. I

capstan

lower

reel

and

capstan

worn-out

or

function

I

motor.

eliminate

in position. I

oil with

torque

I

oil. I

tension.

oil. I

re-adjust

reel

shaft

assembly

I

than

belt. I

in position. J

oil. I

I

shaft

if

tension

belt. ]

replace
provides

pinch wheel

Idler.

motor

properly.

I

starting

capacitor

of

clutch

mate-

reel

shaft

not

rotate

smoothly.

and

sticking

to

idler

or

mo-

bakelite

correctly.

.

not

rotate

or

not

does

no

capacitor

of

clutch

shaft

not

rotate.

warped and

and

strengthen

matenal.

if

both Sides.

mate-

assembly.

stick-

this

reel

on

tester,

and

replace

motor

if

coil

IS

broken.

Clean and re·lubncate oilite metal. \

foreign

matter

for

free

rotation

of

rotor.

screw.

\

cotton

swab

soaked

in alcohol. j

and

replace

motor. j

screw. 1

mountmg

screw. I

!.

pinch wheel pressu,re.

assembly:

relubricate.

If

not

repairable.

re-lubricate

standard. I

and

re-lubricate

assemblies.

mounting screw. I

Lubricate oilite

]Check motor torque.
lif

back

Replace

not

adjustable.

flywheel. I

defective

part.

smooth

rotation.

pressure.

metal

Wipe

off

oil. J

Tighten

motor

bushing

Check and
Check.

assembly.

/Check

tor

Check

Check take-up

Check guide roller. Re-Oil

Check

Wipe

Check

Tighten

Check rewind idler. Clean and re·Oil-l

Check

Clean and re-oil

Replece

Check

Check guide roller. Re-oil

Check and

motor torque.

if

required.

and

and

off

internal

motor

supply

not

repairable.

supply

tension.

readjust

clean

replace

replace

oil. l

bushing

replace

oilite metal. J

oilite metal. J

reel

Clean

l

in

center

moWlting

and re-oil

reel

shaft

reel.J

idler. I

mounting

reel

shaft

I

reel

shaft

reel. l

I

Replace

shaft

and

re-oil

of

idler.

screw.

idler

wheeL

reel

Replace

I

assemblyj

or

replace.!

screw.

assembly. I

Replace

assembly.

or

replace.

1

I

l

shaft

mo

-~

l

motor I

I

I

I

I

I

J

I

_j

FAST-FORWARD

Turn

the

FAST

position,

and

the Lever (C).

between
Sp
bushing

reel

come

(Gl,

take-up

the Plastic Roller IFl

mdle and

spindle.

off

thereby

the

to

transmit

the

reel

allowing

reel.

Fre

e Rotation

MECHANISM

FWD-REWTND

the cam

upper

At

The

the
the
spindle

(B

)

Tdler tDJ

part

motor

sam

e time,

to

fast

winding

knob (A l

under

moves

above

of

the

rotation

the

free

the Supply Reel Spindle

High-Speed

to

the

knob

in

the

rotating motor

to

brakes (H )

of the

tape

Rotation

~F

AST

FWD •

pushes

to

the

Take-Up Reel

the

take-up

and

onto

up

space

driv

the

{I)

J

REWIND MECHANISM

Turn

the

l01

(

v~

\.....

IC

FAST

position,

Lever (

ween
(E)
speed
pulley
time, Brakes (H) and

free

tape into the

and

C)

up.

the

upper

and

the Intermediate Pulley (F) to transmit

rotation

to

the

the take-up reel spindle r

High-speed

FWD-REWIND

the cam (B)

The

Idler (D)

part

of

of

the

motor

Supply

supply

Reel

(I

)

reel

Rotation

the

Spindle

come

at

under

moves

rotating

through

off

n.

thereby

a fast

knob fA)

the

into

to

"REWIND~

knob

pushes

the

space

Motor drive bushing

the

the

Int

ermediate

(G). At

the

speed.

Free

the

reel

spindle

rewinding

Rotation

the

bet

high-

same

to

the

-

~-==-

~tP

~

(

0

"--.__/

\.-;

, i I

·

II

'

(\~

·J

Q____D--o

;..~

0

'-......-/

r '

I~

Modes

1al

STOP

(b) FAST-FORWARD

c) REWIND

d) RECORDING

PLAYBACK

NOTE

10

of

Operation

S:

X-m

0-

Pinch
Roller

I

II

arks

marks

ITo!r.e-up [

Idler
Wheel Wheel

X

X

X

0

0

indicat

es

"engagedh

!iewtnd

Idler

X

X

0

I

~open"

Take
up-s1de

Brake

X

X

0

X X

and

0

I

ST

OP

-

Supply­side

! Brake

0

X

X

0

X

0

X

(A
reel

the

CONTROL

Push
),

and

spindles.

brake

As

reel

the

Stop

(B)

depress

rubber

spindles,

lever

to

reel

depresses

no

friction works

qSTOPh position, brake rubber

spindles

to

stop

the

plastic rollers

on

rotation

the tape

of

under

itself.

the

~SCREW(2)

~S

CREW

c:::=====t=:s::P===:f

(2~)WASHER

FELT

WASHER

WASHERS--

(:2-g)

(33

~~~~

~-

~~~~

H~~~~:JIW

~

C::::==l===:r

~~

___ !3)

.....

,

--~

E~fS~

~

_ _

REEL

SPINDLE

FELT

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SPRING

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@RETAINING

CLUTCH

STAR

_

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S~P~I~N=DL:E~('i?~~N

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WASHER

(

:z

7}

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SPRING WASHER

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(

3)

TABLE

DRIVE RING {).5)

3o)

INING RI

--------~~--~~~

Tt

N G p

NUT

------------~--~

(z Y)

RING

(3J)

NG

(zq)

WASHER -

{29)

---

LA

T~E

:=:~;;~

-------.

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SPINDLE

FELT

CLUTCH

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---

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__

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r-~

®RETA

CLUTCH DISC

-

WA

-

®RETAINING

~

/.,B

1

1

TABLE

TABLE

WASHER

PLATE

INING RING

SHERS

ASE

PLATE

RING

SUPPLY

REEL

SPINDLE

#

62-49

ASSEMBLY

TAKE-UP

REEL

#62-50

SPINDLE

5-20-64

DATE

ASSEMBLY

A

REV. APP

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HE.AD

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CONTROL

'PLAY

BLOCK

L

EFT

CRiiht

DIAG~MA

AMP.

amp

MOOE.

OttLY

. tile

Scl~rte)

L I

650

- 1&70

1.

NO

2.

SOUND

SOUND.

(a)

Pilot

(b) P

(c)

Tubes

(d)

One

One

(e)

BUT

(a)

Hum

(b)

Hwn not

light

and
(1) D
(2)
(3)

ilot

light
(1) D
(2)

lit.
(1)
(2)

ehannel
(1)
(2)
(3}

Output

(4)

Output

(5)

Output

channel
(1) Defective
(2)

Defective
(3)
(4)

Open

WITH

LOUD HUM.

controllable
(1)
(2)
(3)
(4)

(5)
(6) Grou
(7)

(1)
(2)
(3) D
(4) H igh rE-sistive sol

tubes

efective
Defective
Defective

anrl

tubes

efectivc
Defective

but

no
Defecth·e rectiUer tube.
Power

Speaker open
External

Incorrect

Impr

DefectivE>

Defective

supply

normal,

tube
circuit
transformer

normal.

coup

oper

Misadjusted

Improper hea
Leaky

coupling

nd

loop

High

resistive

controllable

Leaky

coupling

efective

PLAYBACK

do

fuse.

A.C.

power

do

power

conn

sounci

other

speaker

defect.ive.

other

head

input

voltages.

ling capacitor

with

head

hum

input

d l

driver

power

PROBLEMS

not

light

cord

or

its
switch.
not

light

in

power

either

channel

de[ective.

defective.

channel

head

connection.

preamp

or

control.

shit>ld

or

input

citor.

external

joint

output

filter.

joint at

up

transformer.

e-cti

on

from

component

or d.isconnected

jack

defective.

or

or

volume

lead

controls.

lubes.

ead
capa

between

solder

with volwne

or

capacitor

supply

der

up

and

the

connection.

but

the

transformer

channel.

defective.

dead,

(not

.

has

faint

tube

.

shorted

grounding.

tube

grid

equipment

at ground

control.

tubes.

between

driver

ground

motor

motor

(not

even

even faint

hum

but

grid.

lead

connec

and

connection.

does

does

run.

primary

faint

no

positionin

and reco

tion.

output

not

run.

leads.

bwn).

hum).

signal sound

g.

rder.

tube.

.

3.

LOW

VOLUME.

(a)

(b) Record l<Pnsitivily

4.

DISTORTION

(

a)

(b)

Record

(1)
(2)
(3)
(4)

(1)
(2)

(3)

(4)

(fi)

.

At

low volume.

(1)
(2) Tncorr
(3) Leak")'

At

any

(1)

(2) Defective

(3)
(4)

sensitivity

Dirty

Tape

Defective
Defe

Defective amplifier
Def
Defecti
DefectivP
Leaky feedback

Defective

volume

Same

Defective
Bad

beads.

threaded

ctive

ective

ve

ect

coupling

but

as 4 (a).

wow

normal

bead.
tape

lifter

also low

rectifier tube

plate res

output

tube.

plate

voltages.

woJ:Se

loudspeaker.
feedback

and

flutter in

according

with

oxioe

.

acc

ordi

tube

if

istor

causing

transformer.

capacitor.

capacitor.

at

high

network.

to

side

ng

to

if

only

holh

volume.

tape

transport.

the

away

the

one

sides

low

VU

Meter.

from

VU

Meter.

side

low.

voltage.

low.

(see

the

nead.

deck

problems).

22

RECORDING

1.

NO

RECORD.

(a)

(b)

2.

DISTORTION.

(a)

(b)

3.

ERASE

PROBLEM

(

a)

(b)

PROBLEMS

VU

Meter

not

(1.) Defective
(2)

Input

(3)

VU

VU

VU

No

Po

R/ P slide

Meter

reads

(1)

Defective

(2

)

Broken

(3)

Defec

Meter & amplifier

(1)

Faulty

(2

)

De

fective r

Meter

(1) Excessive

(2)

Defe

(3) D

efect

(4

)VU

Meter

.

erase.

(1)

Faulty erase

(

2)

Faulty

(3)

Open

( 4)

Tape

or

erase

.

(1)

Dirty erac;e

(2) Defective

(3)

Low

(4)

Def

(Prerecorded

working

jack

tive record

normal

ctive R/ P

ive

erase

lifter

erase

ective

in

microphone.

contact

switch

alright

R/P

wire

in

monitor

oscillator

eco

rd

but

signal

slide

microphone

reading

head.

erase

cable

coupling

not

head.

erase

voltage.

head

tapes

record

mode.

poor.

not

functioning.

in

record

head.

record

bias voltage.

amplifier

input.

functioning.

head.

elevation.

mode.

circuit.

current

normal.

cur

rent circuit

switch.

or

incorrectly.

or

con

nec

capacitor.

play

alright)

cir

cuit

component

component.

monitor

radio/ phono

distorted.

tion.

.

.

4.

5.

6.

7.

HIGH

BACKGROUND

(a)

(b ) R

LOSS

OF

HIGH

(a)

LOW

SENSITIVIT

(

a)

LOSS

OF

LOW

(a)

NOISE

Hiss.

(1)

Magnetized

(

2)

Defective

(

3)

'

Hash

(4)

Dir

umblin

(1)

(2)

(3) Excessive
(4)

ect
g.
Defective

Distorted

Exces!iive

FREQUENCIES

No

sparkle.

(1)

Dirty

(2)

Record

(3)

Wnrn

Y.

VU

Me

ter

reads

(1)

Dirty

(

2)

Def

(3)

(4)

eciJve

Defective reco

Defective

FREQUENCIES.

No

bass.

(1)

Mismatch

(2)

Incorrect

LEVEL

tape

' on

oscillator

current

tape.

oscillator
tape
tape

.

heads.

bias

beads

normal.

heads.

heads.

tape.

of

sped.

ON

TAPE.

beads.

.

output

leakil1g

output
pressure
'wrap'

incorrect

.

rd

current

impedances

(fast)

(his

s,

sc

waveform.

to

heads.

waveform.

against

around

voltage.

circuit

of

ratch

heads.

beads.

input.

y)

component.

23