RCA 73-B Series, 73-B MI-11825, 73-B MI-11826 Instructions Manual

www.SteamPoweredRadio.Com

www.SteamPoweredRadio.Com

www.SteamPoweredRadio.Com

BROADCAST

INSTRUCTIONS

EQUIPMENT

Type

73-B

Prolessional Recorder

(Ml-11825)
(Ml-11826)

RADIO
RCA

IN

0

Pl'II~

...

VICTOR

A •

.

■

U .

CORPORATIOn

v1s1on

0 1

OF

AffiERICA

CAmoen,

n.J

.

.

www.SteamPoweredRadio.Com

Figure 1-Type

73-8

Professiono/ Recorder

www.SteamPoweredRadio.Com

1

DESCRIPTION

Appficatio

The

signed

33¼

applications

in

large

highly

is

programs

ing
hearsals, auditions

■

r

■

T

The

diameter

inches
rubber

base

turntable

the
any
When

without

down

rubber

alongside

pressed,

Turatable Drive

The

motors coupled

■

Type

RCA

make

to

78 revolutions

or

numbers

suitable

for

table

turntable

will

and

diameter

in

on

mat

may

and

a

three drive holes

of

one

desired

is

it

drive

that

so

. A plunger-release

mat

the

drive

the

turntable

high-quality disc recordings

for

of

the

be

drive

holes,
it

drive

73-B Professional Recorder

may

It

minute

per

preparing

records

for

of

can

broadcasting stations

use on

and

future

similar

recorder is 17½ inches

the

accommodate

¾-inch

and

turntable

easily cleaned.

mounted

is

pin

make

to

drive

this

below

be

will

and

,

pin

comes

pin

is rim-driven

wheels.

drive

to

.

masters

made.

be

from

The

in

broadcasts,

applications.

blanks

up

thick. A removable

provides a

Near

in

use

pin

button

when

back

by

good

the

over

record blank.

the

record

of

may

surface

the

is

this

position.

into

~ncbronous

two
Both

which

be

motors

de-

is

either

at

used

be

which

recorder

record-

re-

for

in

¼

18

to

record

center

of

6u

blanks

pressed

the

of

mounted

button

are

controlled

switch

motor
automatically is applied

bringing

rubber

Feed

The

bead

it

shock-mounted

Screw

feed screw is designed so

carriage

inside-out recordings

feed-screw

The

system between

Mounted

dle.

friction

a

is

feed screw.

the

of

down

and

up

by means

This

the

on
the

outside-

top

the

fr

.
direction

the

setting

om

is

housing
and
scale
cates

and

at

wheel

wise to facilitate adjustment to

per

es

lin

of

wheel is adjusted at

in

the

against
eng

pressure

is

which

ON-OFF

one

by

the

When

.

■

a

may

d

to

Drive

be

quickly

without

drive

drive

the

drive

the

on

which

wheel

The

the

over

on

knob

a

of

adjustment selects

cut.

of

ouuide

in

of

the

in

of

lines

of

recordings. A release lever mounted

housing

the

ange

fl

s

A

ch.

the

the

sition (

po

aged

lever

lever

the

to

a stop.

from

is

rim

The

the

turned

OFF, a

the

of
motors
motor

that

ouujde-in

either

for

used

changing

a pulley-and-belt
shaft
shaft

of

and

above

turntable

consistS

drives a flange

friction wheel may

diameter

entire

the

the

An

the

per

outside

drive

of

recording

the

muminated

shaft

­both

ch for

in

housing indi-

disengages

turned

when

des

the

provide

to

the
clockwise

to

pring

factory

flange

attached

when

turned

the

the

of

counterclock-

operates

a

brake

turntable,

doubly

are

.

board

recorder•

or

feed screws.

spin-

turntable

end

the

on

moved

be

flange

the

drive-shaft

pitch

pointer

and

inside-out

friction

the

number

ed

ir

friction

the

proper

the

release lever

).

Power Supply Required

l 2S volts

to

lOS

cycles

60

cycles (

SO
Turntable-drive

Lamps . . . . . . . . . . . . • . . . . . . . . . . S

Pilot

Total

Spinllin1

-11825 )

(MI

-1182

Ml

motor

6)

motors

hen

(w

. . • . . • . . . . . . . . 8S watts

operatin1)

Turntable Speeds

33¾

or

78

rpm

(±½%

)

Turntable Diameter

up

blanks

for

(

ches

in

17½
¾I

r

■

T

0.2%
0

0.0

0.14% (

.4%

inch

-

table

■

7%

)

thick

Speed Re9ulatlon

)

peak

to

peak

(

(peak

rms)

(

rms

)

to

peak)

at

at

78

331

rpm

,~

at
at

rpm

18¼-inch di

to

rpm

78

rpm

33¼

TECHNICAL

90

4S

1

ameter

(wows)

watts

watts

watts

and

DATA

Recordln9 Pitch

variable

ly

(a )

Depth

b)

(

Depth

ote:

N

ous
provided

ts

of

or

ubi,ul

Wilh

31¾ inches

-22¼

- 280

ut

ho

Wit

0 inches

-2
0 inches

-3
0½

-2

JB-243

See

data.

Feed

outside-

d

■

a

inches

inches

pounds

~•bir,•I

in

Continu
deten

Direction

Inside-out

Dimensions

Heisht-20
Width-

Weisht

Heigbt
Width

technical

eps

st

in

in

Wel9H

ches

for

40

152 lines

to

96

8 lines

of

-11850-C Recorder

Ml

per

per

inch

with

ch

in

.

Head

IB-24383

www.SteamPoweredRadio.Com

2

Spiralling

A separate self-braking
screw to
motor
a pulley-and-belt system. A non-locking
switch
ate
inch
table

duced

provide

is coupled

near

this motor.

when

the

speed

of

in

proportion

the

drive-shaft

The

turntable

33 ½

start

to

motor

and

the

feed-screw

housing

spiralling

speed is 78

rpm

the

to

the

speed change.

overdrives

finishing spirals.

is

pitch

is six lines

rpm.

spiralHng

Carriage

The

recorder-head carriage is free

the

feed-screw

with

the

raised

or

is raised from
automatically disengages
arm

automatically engages

leased

the
justS

the
tion, the
the
record by

from

The

center

angle

the

The

stylus-lowering lever is used

stylus.

surface

tube

until

feed-screw

non-cutting position.

the

of

the

depth

When

feed-nut

of

operating

tube

the

cutting

rest position.

thumb

the

nut

cut.

The

of

the

cutter.

the

carriage is

arm

is engaged,

record, ready

this lever.

a latch locks

when

position,
from

when

on

left-hand

the

carriage is

When

the

the

the

carriage

in

the

and

to

be

the

to

feed screw;

thumb

to

lowered

Recorder Head

The

compensator, transformer, series resistor,
high-off-low switch,
are recommended
Recorder Head
a complete description
the

instruction

Calibrated

Four
for 96, 104, 112, 120, 128, 136, 144
inch:

One
One
One
One

Scales

timing

for

inside-out
for inside-out
for outside-in
for

outside-in

for

are

book

scales

pilot

lamp

use

all

built
of

the

(IB-24340)

are

provided, each

recording
recording
recording
recording

and

receptacle

with

the

into

the

Ml-11850-C,

shipped

and

at

33 ½

at

78

at

33 ½

at

78

the

feed

This

drive

shaft

push-button

used

to

oper-

For a turn-

pitch

is

rotate

the

feed-nut

carriage

raise

standby posi-

stylus is near

recorder.

152 lines

rpm,

rpm.

about

the

carriage

in

carriage

arm

is re-

controls

nut

or

lower

to

which

MI-11850-C

refer

with

it.

calibrated

rpm,

rpm,

by

per

re-

the

the

ad-

the

For

to

per

comparison
known
proper
made.

The
record surface. A small
justable
on-off toggle
microscope

of

the

dimensions thus

standards for

interpretation,

microscope may

arm

to

illuminate

switch

arm.

for

Transformer

A transformer

plies

the

power

On

some

of

for this purpose.

the

mounted

for

the

units

INSTALLATION

Unpacking

Take

extreme
equipment,
assembly.
entering

the

Connections

Make

all

board

at

the

power

of
diagrams
ures 3

the

leads
recorder.

and

Mounting

Mount
Install
machine screws
turntable

imum
allow
assembly.
sions
on
plane.

the

When

clearance

for floating

of

the

the

skid

the

Refer

care

in

with

special

Prevent

audio

for

4).

the

over

assembly

any

turntable-spindle bearing.

connections

front

of

to

the

TB-1

Refer

the

proper

recorder

cabinet

cabinet

recorder.

and

the

spindle

around

of

to

figure 2

over

is

the

are

obtained

recording

superior

be

lamp

this

on

pilot

two

transformers

unpacking

regard

dirt

or

the

recorder.

terminal

to

the

terminals

on a sturdy

the

washers provided. Place

carefully.

not

used, allow

the

sides

shock

for

Be

sure

exactly

work,

recordings.

moved over

is

mounted

the

record grooves.

lamp

is

mounted

the

recorder base sup-

lamps

and

and

handling

to

the

foreign

to

the

TB-2 terminal

Connect

board

schematic

to

be

recorder

¼-inch

of

the

mounting

the

mounting

the

four

wood

in

a level

and

may

the

on

the

heater

a.re

supplied

microscope

matter

the

at

the

and

wiring

used (fig-

flat surface.

using

recorder
on

the skid

dimen-

blocks

horizontal

with
with

be

entire

ad-

An

on

the

kit.

the

from

a-c

rear

two

the

min-

to

I

Microscope

A high-quality 36-power microscope

arm

ciated
side
so

that
object viewed.
groove and wall

assembly is

the

turntable. The

each division represents 0.001 ·

This

widths

with

an

provided

microscope scale is calibrated

permits

of

for

mounting

inch

on

aetual measurement

the

record face,

and

along-

asso-

the

of

by

Installing Microscope

Mount

corder

Pull
through
threaded
ondary

the

base

by

the

two

the

shaft,

winding

microscope-arm assembly

means

of

leads

opening

and

connect

terminals

the

from

on

threaded

the

microscope

the

recorder

these leads

of

transformer

shaft

on

the

provided.

lamp

near

to

the

T-1 as

re-

the

sec-

I