NORTHERN ELECTRIC CM Series User manual

N.E.-C . · 739
MANUAL
'
MAY 1958
CONTENTS .
SECTION 1
·DESCRIPTION & SPECIFICATIONS
SECTION 2 • IN.
ST ALLA TION & OP E_ RA TION ·
.SECTION 3 • ACCESSORIES
SECTION 4
·APPLICATION NOTES
SEC110N ·s
·SERVICE INFORMATION
SECTION 6 -
www.telephonecollectors.info ©Jeff Lamb

N.E.•C. 705
WARRANTY
N. orthern Electric Company Limited warrants this
equipment to be free ~rom defec~s in material and
•
workmanship under normal use and service, its
obligation under this warranty being limited to shipp-
ing a replacement for any numbered part or parts
thereof, except vacuum tubes, which . shall within
ninety (90) days from the date of purchase of such
equipment by the original retail purchaser be re-
turned to Northern through its distributor or dealer
with tr ans port at ion charges prepaid, and which
-examination shall disclose to Northern's satisfaction
to have been thus defective, such replacement will
be shipped charges collect; this warranty being ex-
pressly . in lieu of all other warranties expressed or
implied, and Northern neither assumes nor author-
izes any representative or other person to assume
for it any other liability in connection with the sale
of _its· products. ·
This w' arranty shall not apply to any equipment \yhich
shall have been repaired or altered in any way so as,
in Northern's opinion, to affect its stability or re-
liability, nor to any equipment which has been sub-
jected to misuse , neglect or accident, nor to any
equipment which has had the serial number altered;
effaced or removed.
"Northern Electric r .. ser~es the right, without notice, to make such changes in equipment,
design, or component., as progress in e· ngineering or manufacturing methods may warrant."
Northern Electric
COMPANY LIMITED
BELLEVILLE, ONTARIO .
ASSOCIATED DISTRIBUTORS:
CANADA- DOMINION SOUND EQUIPMENTS LIMITED, 4040 ST . CATHERINE ST. WEST, MONTREAL
u.s.A .-ALTEC LANSING CORPORATION, 1Sl5 s. MANCHESTER AVENUE , ANAHEIM, CALIFORNIA
FOREIGN (EXCEPT U.S . A.)- WESTREX CORPORATION , 111 EIGHTH AVENUE, NEW YORK 11 , U.S.A.
www.telephonecollectors.info ©Jef Lamb

N . E . • C. • 741
DESCRIPTION:
Northern Electric
CM MAGNAPHONE
PART II
lss . 1-5 /58
SECTION 1·
PAGE I
The Complete Master Magnaphone is an economical and efficient loudspeaker intercom sys-
tem which provides intercommunication facilities fo r industries , offices, institutions and homes.
The cabinets, suitably styled for office and home use as well as industrial applicat i ons, are
built to withstand years of rugged use and yet retain their original appearance .
All Master System (6 stations maximum)
FEATUR·ING: * Remote Answering.
* Busy Signal.
* Individual Volume Control.
* Confidential Handset .
* loud Paging .
CM-SA
BUSY
S IGNAL
INDICATOR
PRESs-TO · TAL K
RELEASE · TO·LISTEN
SWITCH
SPECIFlCATIONS:
Impedance, Input and Output:
STATION
SELECTOR
SWITCH
45 ohms.
OFF · ON
SWITCH
PILOT
LAMP
CMA-SA
BUSY
SIGNAL
INDICATOR
PRESs-TO·TALK
RELEASE · TO·LISTE N
SWITCH
STATION
SELECTOR
SWITCH
POWER CORD
\ 117v . AC / De
0. 25 Amp s.
Frequency Response : Specially adjusted for maximum intellegibility of voice trans -
mission .
Gain:
Power Supply :
Vacuum
Tubes :
NOTE :
Colour:
Dimensions :
Weight : CM-
SA;
CMA-SA;
80 db nominal.
117 volts AC/ DC at 0. 25 amps.
1- 12AX7
(voltage Amp Iifier)
1- 35W4 (Rectifier)
1-50C5 {Output Amplifier)
As the loud speakers are disconnected when the selector swit-
ches are in standby position, the residval noise is zero.
Rosy
Beige .
7•
1/ 2" wide x 6 • 1/ 8" high x 5- 1/2" deep.
4 lbs . net; 6 lbs. shipping.
5
lbs . net; 7 lbs . shipping .
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PART II SECTION I
lss. 1- 5/ 58 PAGE 2
N .E . -C ,- 74 2
Northern Electric
CM MAGNAPHONE
BLANK
PAGE
www.telephonecollectors.info ©Jef Lamb

N.E.-C . -743
INSTALLATION:
Northern Electric
CM MAGNAPHONE
PART II
lss. l -5/ 58
SECTION 2
PAGE I
The two following basic systems are presented to illustrate the installation of a Complete
Master System. Both systems use the same basic units, without modification, and a choice of
either system will be dependant upon requirements and , building arrangement. The number of
stations used in a system will depend on the number of locations desiring intercommunication
and may vary from a minimum of two to a maximum of six.
Although a CMA- SA Master Station (amplifier unit) may be placed at any point from A to
F in either system, it is suggested it be located in a position where its operator will be in
control of the system and turn the unit on and off at the beginn ing and ending of each day . It
is also recommended that it be located near an AC outlet .
CAUTION -FOR SYSTEMS "A" (, "B":
h is essential that twisted pairs be used for station interconnection. Each twisted pair
should be connected to a pair of odd and even numbered terminals, e.g. one pair for terminals
l and 2, another pair for 3 and 4, another pair for 5 and 6 etc . Individual conductors in each
twisted pair must not be cross connected. That is, odd numbered terminals are connected with
one conductor of a twisted pair and even numbered terminals are connected with the other con-
ductor of that same twisted pair .
SYSTEM "A" :
The "A" System illustrates the "in- line" or direct wiring method of installation. A multi-
conductor cable runs through al I station locations as shown in the fol lowing block diagram .
STATION
A
CMA-5A
STATION
B
CM-5A
SYSTEM A - BLOCK DIAGRAM
STATION
c
CM-5A
STATION
D
CM-5A
STATION
E
CM - 5A
STATION
F
CM - 5A
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©Jef Lamb

~I
....
'"
..
TYPICAL INTERSTATION WIRING
II r-1 r----1 r:-i r-1 r-1
IN
"-1 (?
? ? ? ? ? "\ I
OUT I I~ I l~I I '::::::: t I '::::::: I I '::::::: I I
"=" I
- - - - - t<xJt - - - - - t<xJt - - - - - i-\Vt - - - - - ~I
SEE NOTE 2 ,-..... ,-..... SEE NOTE 2
2
3
4
5
REM c @
@
@
SPARE
STATION .
A
TERMINALS
STATION
B
TERMINALS
STATION
c
TERMINALS
STATION
D
TERMINALS
NOTE. 1. For ease of representation, station terminal boards hove been illustrated as shown in the
Typical lnterstotion Wiring diagram.
2. lnterstotion wires to terminals S and 6 ore required on the initial installation only when a
busy signal tron,former kit hos been installed in a system .
See CAUTION nol:e under insl:allal:ion.
- - -
@
@
@
STATION
E
TERMINALS
(/)
-I
@
@
@
STATION
F
TERMINALS
(/) ~ I -ON0<>1041>0UIOOIO(OO
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www.telephonecollectors.info ©Jef Lamb

N.E.•C.•745
SYSTEM "B" :
Northern Electric
CM MAGNAPHONE
PART II .SECTION 2
lss. 1·5 /58 . PAGE 3
System "B" illustrat es the centralized or junction box wiring method of installation where
all wires from outlying stations connect to appropriate terminals in a junction box. Suitable
strapping provides the necessary through connections to other stations .
STATION B
0 0
20 21
0
18
/ 0
SYSTEM B - BLOCK DIAGRAM
STATION
F
CM-5A
STATION
E
CM-SA
STATION
A
CMA-5A
BO X
STATION
D
CM-SA
STATION
B
CM-SA
STATION
c
CM-SA
TYPICAL INTERSTATION WIRING
Station A: The numbered terminals of
stat ion A connect to the cor·
responding numbered termi nals
of row A on the junction box.
17
0
( / /
Station B: The numbered terminals of
station B connect to the cor·
responding numbered
terminals
of row B on the junction box. '(
I
, 1
11
, 1
, 1
11
I
16
0
15
0
14
0
13
Stations C,D,E, F: Similarly connected as for
stations A and B.
AMP
IN
r\
JUNCTION BOX
AMP BUSY
OUT SIG STN A
r\ r\ r\ r\
STN A 0 0 0 0 0 0 0 0 0 0 0 0
I 2 3 4 5 6 7 8 9 10 11 12
STN B f) f:}
I '--~-++++----------!-----" 4 / 5 / 6
'----++++-++------- -- -4- -- -----' / /
LL--- =========== ====== ==-::...~ _/
~=S=E=E=N=O=T=E=2==========::t:==========================:::::::._/
NOTE·: 1. Terminals on junction box are not number ed consecutively .
2.
lnterstation wires to terminals 5 and 6 are required on the initial installation only
when a
busy signal transformer kit has been installed in a system.
SEE CAUTION NOTE UNDER INSTALLATION.
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PART. II
lss. 1·5 /58
AMP
IN
r---\
STN AO 0
SECTION 2
PAGE4
AMP BUSY
OUT SIG
;--\.
I\
0 0 0 0
'
Nortnern Electric
CM MAGNAPMONE
CM SERIES JUNCTION BOX
CALLING CIRCUITS TO
STN A I
STN B
STN C
STN D STN E
STN FI
;--\.
I\ I\
;--\.
;--\.
I\
0 0 0 0 0 0 0 0 0 0 0 0 0
I 2 3 4 5 6 7 8 9 10 II 12 13
14 15 16 17 18
l9 REM
POS"'I
STN e O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
I 2 3 4 5 6 9 10 7 8 II 12
13
14
15 16 17 18
20
STN CO
0 0 0 a 0 0 0 0 0 0 0 0 0 0 0 0 0 0
I 2 3 4 5 6 9
10 II
12
7 8
13 14
15 16 17 18 19
REM
POS
12
STN o0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
I 2 3 4 5 6 9 10 II 12 13 14 7 8 15 16 17
18 20
STN EO
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
I 2 3 4 5 6 9 10 II 12 13 14 15 16 7 8 17 18 19
REM
POS "3
STN F0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
I 2 3 4 5 6 9 10 . II 12 13 14 15
16 17
18 7 8 20
OPERATING TABLE
When installation has been made in accordance with system "A .. or "B .. wiring diagrams,
the various station selector switch posit i ons will be in accordance with the following operating
table . This table applies to both, Systems A and B.
OPERATING TABLE
STATION
#(
#2
A ® ©
B © ©
c © ®
D © @
E © @
F
~ ®
SW ITCH PO SITION
• 3
.... ,
® ©
@ ©
@ ©
© ©
© @
© ®
' "" !'ii
®
®
®
0
0
©
0
" 1 0
STANDBY
STN SELECTOR SWITCH
Example : Station A calls station D by turning h is selector switch to position 3.
MASTER GAIN CONTROL :
A sc r ew-driver adjusted type gain control, which is accessible through a knockout at the
rear of the CMA-SA Master Station, is provided for adjusting the system level.
INTERSTATION CABLE :
A good grade of interphone type cable, utilizing colour coded and twisted pair wires, is re-
commended. The length of cable between stat i ons will determine. the wire size and the following
chart can be used for this purpose.
Wire Gauge
22
19
18
16
Recommended Maximum Di stance Between
Stations {Busy signal current limi tation)
500 ft.
1000 ft.
1100 ft.
2000 · ft ~
N, E, • C , • 74 6
www.telephonecollectors.info ©Jef Lamb

Northern Electric
CM MAGNAPHONE
PART II SECTION 2
lss. 1• 5/ 58 PAGE 5
OPERATION - ALL STATIONS:
CM-SA
CMA-SA
BUSY SIGNAL PRESS Tll TALK
SELECT STATION
ON-OFF PILOT BUSY SIGNAL PRESS TD TALK SELECT STATION
INDICATOR RELEASE TD LISTEN
SWITCH LAMP INDICATOR RELEASE TD LISTEN
TO CALL ANOTHER STATION:
1. Select the station to be called by turning the station selector switch to the desired
position.
2. Depress "Press-To - Talk" switch to talk· release to listen .
3. On completion of conversation, restore the station selector switch to the "Standby"
position.
TO ANSWER AN INCOMING CALL :
1. When incoming call is heard, depress "Press-To-Talk" switch to talk - release to
listen.
NOTE: When answering an incoming call, it is not necessary to move the station selector
switch off the "Standby" position.
EXTRA DESIGNATION STRIPS
N.E.• C.· 747
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PART II SECTION 2
lss. 1-5 / 58 PAGE 6
N . E . -C.•748
Nort/Jern Electric
CM MAGNAPHON,E
BLANK
PAGE
www.telephonecollectors.info ©Jef Lamb

N.E. • C. • 749
Northern Electric
CM MAGNAPHONE
PART II
lss. l-S/S8
SECTION 3
PAGE I
ACCESSORIES
R19109-60 VOLUME CONTROL KIT:
This kit is available for installations where it is required to arrange for different sound
levels at CMA-SA and CM- SA Master Stations . The kit consists of a 200 ohm screw-driver
adjusted potentiometer, complete with leads, mounted on a bracket .
•
INSTALLATION:
NOTE:
This kit, which is a universal item, is supplied with some parts, that
are not necessa ry for installation in a CM- SA or CMA- SA Master Sta-
tion. The mounting bracket and hex nut are not essential for instal I ci-
tion in either unit and it is recommended that the strap and leads sol-
dered to the potentiometer, be removed before the kit is installed.
MOUNTING:
CMA- SA;
1.
Remove the chassis from its cabinet and, with the speaker facing you,
turn it
up· side down.
WIRING:
l.
2.
3.
4.
2.
3.
4.
Loosen the output transformer mounting screws and remove the one on
the left hand side.
Mount the potentiometer, with the terminals up, in the 3/8" hole be-
hind the output transformer.
Replace the left hand output transformer 'mounting screw and tighten
down the transformer.
CM-SA; l. Remove the chassis from its cabinet and, with the speaker facing you,
turn it
up- side down.
2. Mount
the potentiometer in the 3/8" hole located on the rear flange of
the chassis to the right of the speaker or in the adjacent 3/8" hole.
NOTE: Potentiometers mounted on the rear flange of the chassis, wil I have
the shaft directly in I ine with the cabinet knock· out and may be ad-
justed externally if the knock- out is removed.
Electrical connections for the CMA-SA and CM-SA are as follows:
J
Transfer one speaker lead to the right hand terminal of the potentiometer.
Connect a length of wire between the centre terminal of the potentiometer and the
free speaker terminal.
Connect a length of wire between the left hand terminal of the potentiometer and
the other speaker terminal.
Reassemble the unit.
SCHEMATIC
!
PRESS -TO - TALK SWITCH
r---- - - - -,
I
1
VOLUME CONTROL I
I KIT I
L _______ _J
<J
LSI
45.n
SPEAKER
www.telephonecollectors.info ©Jef Lamb

PART II
lss . 1• S/ 58
SECTION 3
PAGE 2
Northern Electric
CM MAGNAPMONE
R19726A HANDSET:
U1 RECEIVER
UNIT
Where confidential communication is de-
s ired or essential, a telephone handset is ovoi 1-
oble. As illustrated, the R19726A Handset
mounts in the some manner as a regular tele-
phone set. It connects di rectly to the CMA ·SA
and CM· SA Moster Stations and when the hand-
set is removed from the hook, the loudspeaker
is substituted by the handset attachment and
the unit is operated in the normal manner.
HA1 RECEIVER
UNIT
INSTALLATION :
N.E . -C.·7SO
1. Remove the chassis from its cab i net and, with the speaker facing you, turn it
up · side down.
2.
Insert the rubber grommet in the lower 3/ 8" hole on the bock flange of tbe
chassis.
3. Feed the four conductor coble from the handset through the grommet and tie
a knot about S'' from the end.
4. Connect the red lead from the handset to the terminal at the bott.om of the press ·
to · talk switch which hos on orange lead that connects to the speaker .
S. Disconnect the · orang ~ lead from the top terminal of the press-to-talk switch
(this lead connects to speaker) and connect it to the only blank terminal on t he
top of the press-to-talk switch.
6. Connect the block and white lead from the handset to the terminal at the top
of the press· to - t~I k switch now left free from step S.
7. Connect the green lead from the handset to the some blank terminal referred to
in step S.
8. Re- assemble the unit.
SCHEMATIC
LISTEN
I
TALK
PRESS -TO -TALK SWITCH
r - - - -
w
GN
L_
RED 470.Cl
HANDSET ATTACHMENT I
_J
<]
LSI
45.n.
SPEAKER
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Northern Electric
CM MAGNAPHONE
PART II SECTION 3
lss . 1-5 / 58 PAGE J
R19824-45 TRANSFORMER KIT :
The R19824-4S Tran sformer Kit provides the necessary power for operating the busy signal
lamps in a Complete Moster Magnaphone system. The kit, consisting of a transformer, bridging
resistors and a terminal strip mounted on a metal strip, is completely wired for quick and easy
installation in a CM-SA Moster Station. As a 117 volt A.C. source is required for the operation
of this kit, it should be installed in a CM-SA Master Station adjacent to a power outlet.
INSTALLATION:
l. Using the two drive screws supplied, mount the kit as illustrated in the fol-
lowing photo.
2. When the transformer has been mounted, connect the blat .k lead to terminal
number 6
of the station terminal board, the orange lead to terminal number
3 and
the yellow lead to terminal number 4.
INTERSTATION WIRING:
For interstation wi'ring refer to the S ys te m A and System B wiring diagrams
contained in the Installation section of this manual.
SCHEMATIC
TO TERMINAL ____ ___ __ B_L-.K
6 OF STATION
TERMINAL BLOCK
Rl9824-40 REMOTE -NORMAL SWITCH KIT:
120 .n.
OR
TO TERMINALS
3
&. 4 OF STATION
TERMINAL
BLOCK
This kit, when installed in a CM-SA Moster Station, allows that station to be switched to
"Remote" answering (permits answering without operating the press-to-talk switch) or to
"Normal" for standard operation .
INST ALLA Tl ON:
N . E, - C, - 7 S I
1. Remove the CM- SA chassis from its cabinet and mo unt the switch in 3/ 8" hole
at the left of the front flange. The locat ing pin should be placed in the upper
locating hole .
2. Remove the two orange leads from the speaker terminals and connect them to
the two blank terminals on the remote -normal switch.
3. Run the block and white leads, which ore connected to the remote -normal
-switch, through a hole in the chassis and connect them to the speaker terminals .
4, Run the red and blue leads through the same hole and connect th em to lugs
19 and 20 on the terminal board.
5. Remove
the knock- out in the lower left hand corner of the front cabinet holf-
shel I.
www.telephonecollectors.info ©Jef Lamb

PART II
lss . 1- 5/ 58
SECTION 3
PAGE 4
Nortnern Electric
CM MAGNAPHONE
6. Remove the tab covering the adhesive on the designation plate and mount it
so that the hole in the plate is concentric with the hole which was just cleared
in step 5. Press firmly when in position.
7. To interconnect with other CM Series Magnaphones desiring to cal I this station
as a remote operated unit, run a pair of wires from terminals 19 and 20 (referred
to in
step 4) to terminals 17 and 18 of the other stations. As illustrated in the
fol lowing sketch, cut the buss wires leading to the lugs, on the station selector
switch, that are connected to terminals 17 and 18. Transfer the two wires, that
are connected to the dummy lugs on the back wafer of the selector switch, to
the lugs that were just isolated from the buss wires.
8. Reassemble the unit.
SCHEMATIC
CUT THESE
TWO
BUS WIRES
I -RE;OT; SWIT; ',
I KIT
"0-~~~-+~-0~R:.:.o.. I
f'O'W~H"-~+-~~~~~~
LISTEN
J
TALK
NORMAL I
lI
I
I
~~~~-+-~rO~R-'0-. REMOTE I
BLK
? RED
PRESS -TO -TALK SWITCH
I•
BLUE
L - -_J
<J
LSI
45A
SPEAKER
TO TERMINALS 19 8c 20 ON
STATION TERMINAL BLOCK
N.E.-C. • 752
www.telephonecollectors.info ©Jef Lamb

N.E . -C.•753
Nort/Jern Electric
CM MAGNAPHONE
APPLICATION NOTES
(RESERVED)
PART II SECTION 4
lss . 1- 5/ 58 PAGE I
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BLANK
PAGE
www.telephonecollectors.info ©Jef Lamb

N. E. • C ... 751
Northern Electric
CM MAGNAPHONE
SERVICE INFORMATION:
Pl2 S3
CM- SA TOP VIEW
S2 Pt2 BUSY SIGNAL LAMP HO L DER
CM-SA BOTTOM VIEW
BUSY SIGNAL
LAMP HOLDER_-.
I
\ I
PL2-'"'
Tl R4 Yl
\
LSl
R12 RS PLl
CMA-SA BOTTOM VIEW
PART II SECTION 5
lss. 1·5 / 58 PAGE I
R14 , R15
C6 S2 S3
CMA-SA TOP VIEW
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©Jef Lamb

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0
--I
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LSI
4~ .ll.
SPEA l5£ R
TO MODIFIED
SWITCH POS I TION
TERMINALS DN
CALLING STATION
t t
$· ~
I I
- ~ "
1·-
-- ..0 ·1 :
o--!-J
,--------
• ' Bl. Kl af"
I I
C_J
VOLUME
CONTROL KIT
Rl9109-60
I
I
_ .;J.w ·I
R 470.n.
RED
I
I
I
I
·1.
L_ __ ~ " -~ - --~- -J
OPTIONAL HANDSET
Rl9726A
HOOK
SWITCH OPERATION
STAN~ I
-·7: · ~
IJ
Ii I
~·
Iz I
I I I
I I
I~ I
I 2 I
I~ i
fl_ ,_
- I
L o- -'--- -_J
____ J
REMOTE
SWITCH KIT
Rl9824 · 40
LISTEN
!
TALK
" I
TO
AMPLIFIER
INPUT
-
I
OUMMY
LUGS
I I
·1
I
~ ~ ~
0: ~
..
ii:
BUSY S IGNA L
TRANSFORMER KIT
Rl9B24 · 4~
S3 - IF
'
STBY- ~~~s~1~t i' 8ft's
~Mi'o7..sOTHER
SWITCH
POSITION
. o----@-- 2 ---
o------@-- 3- ~J.T:~rOF
f
~1-
' .=t=:::::::l- ,,_,
•
4_ }
~iT~~LIFIER
~ '
S3-IR ' f~~-}
~·- TO STANDBY
~3 -TERMINALS OF -
~ OTHER STATIONS
. o---@--2-
1 ~1-
TO
OTHER
BUS Y LIGHTS
C AUTION
ODD AND EVEN OIUM8ER
TERMINALS MUST .NOT
BE CROSS"CONNECTED.
NOTES·
SW I TCH
POSITION
TO THIS STATION'S
<f---:-@-STBY - ~ll~ &?J J ~ION
STATIONS
I- ©
REPRE SENTS TERMINALS ON STA T ION TERMINAL BOARD .
2· 0 REPRESENTS TERMINALS ON HANDSET· MTG.
BK
3- WIRING FROM SWITCH •s2" FOR ODD TE~MIN A L CIRCUITRY
IS COLOURED ORANGE; WIR I NG FROM SWIT CH • s2" FOR
EVEN TERMINAL CIRCUITRY IS COLOURED YELLOW.
4· DOTTED LI NE S I NDICATE AS SOCIATED. WIRING ADDEO
WITH KITS.
SWIT CHBANK SCHE M ATIC ·
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www.telephonecollectors.info
©Jef Lamb

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12AX7
50C5
117 VOLTS
A.C./D.C. 5 9 4 4
TO STN. TERM. CD
TO STN. TERM. ®
AMPLIFIER
INPUT
3
200.n
5W
RED
RED
Rll
33.n
V3
35W4
5
RI
6.8 MEG .
+I
133 V. •
VI
12AX7
C6.I
401150
Rl2
210.n
v
2W
-..J_.
C6.2
T 40 /150
Rl3
4. 7K
R6
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R7
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C4
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8
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470K
7
T2
Rl9650A
V2
50C5
C7
5/40V .
I. • • • • • • • • .. A
C2
l .047/600
NOTES:
I. ALL RESISTORS 112 W 40 10% UNLESS OTHERWISE SPECIFIED.
2. ALL CAPACITORS MFD. UNLESS OTHERWISE SPECIFIED.
3. ALL OC. VOLTAGES MEASURED TO B- WITH 20 , 000 OHM/VOLT METER.
AMPLIFIER SCHEMATIC
TO STN. TERM . @
AMPLIFIER
OUTPUT
TO STN.TERM. ©
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www.telephonecollectors.info ©Jef Lamb

PART II
lss. l -5/ 58 SECTION 5
P AG E 4 .
Nort/Jern Electric
CM MAGNAPHONE
Replacement
Parts
CIR. DESCRIPTION
PART
VALUE RATING
SYMBOL NUMBER
CMA-5A (AMPLIFIER UNIT) MASTER STATION
Amplifier Chassis Ass,y
RJ9824-60A
Cl
Capacitor, Ce ramic Disc
.0047 ufd 500V
c2 Capacitor, Tubular Paper .047 ufd
600V
Plast ic Sea l ed
C3 Capacitor, TUbular
Pape r .0047 ufd 400V
Plastic Sealed
C4 Capacitor, Tubular Paper .0047 ufd 400Y
Pl astic Sealed
C5 Capacitor, Mica .001 ufd lOOOV
C6 Capacitor, .El ectrolytic 40-40-40 150V
C7 Capacitor, Electro l ytic 5 ufd 40V
Tubular, Mi niature
LS! Spea ker R!9824· 34 45 ohm
PL! Pilot La mp .15 amp 6 - sv
PL2 Busy Signal Lamp .035 amp 24V
Rl
Resistor, Co m position 6.8 m eg l/2W
R2
Re sis tor, Composition !OOK
l/2W
R3
Resistor, Composition
l OOK
l/2W
R4 Volume
Control
Kl0660 ·57 500K
l/2W
R5 Resistor, Compositio n 5,6K l/2W
R6
Resistor, Composition !OOK l/2W
R7 Resis t c:x, Composition
l Meg l/2W
RS
Resi stor, Composition 470K l/2W
R9
Resi stor, Compo0 sition 150
!W
RlO
Resistor, Wire Wound
200
5W
Rll Resistor, Wire Wound 33
l/2W
Rl2 Resistor, Composition 270
2W
Rl3
Resis tor, Composition 4. 7K l/2W
Rl4
Resistor, Composition 1 20 l/2W
R!5
Resistor, Compos ition 120 l/2W
Sl Switch, On Off
Rl3645-8
S2
Switch, Pre
0
ss - to -talk
Rl9824-35
S3
Switch, St ation
Rl 9824-44
Selector
Tl
Input Transformer
Rl9820A
T2 Output Transfo r mer Rl9650A
VI
Vacuum Tu be 12AX7
V2 Vacuum Tube 50C5
V3
Vacuum Tube 35w4
Pi l ot Lamp Hold«
Busy S igna l Lamp Holder
Cabi n et Asse mbly (FRONT) Rl9824- 50A
HALF
Cabinet Asse mbly (BACK)
Rl9824-52A
HALF
Knob, on · off sw itch Rl9721E
Knob, press•to•talk.
Rl9824· 28
Kn ob, station selector
R! 972!D
Rubber foot kit (4)
R!9824·29
Sp acer & Scr ew Kit
R! 9109·36
CM - 5A MASTER ST ATION
LS!
Speaker
Rl9824 -34
PL2 Busy Signal Lamp .035 amp 24Y
s2
Swit ch, Pre ss - to · talk Rl9824 -35
S3
Swi t ch, Station Selector
Rl9824·44
Busy Signal Lamp Holder
Cabinet A ss embly (FRONT) Rl
9824· 50B
HALF
Cabinet Assembly (BACK) RJ
9824·52B
HALF
Knob, Pr ess -to - talk
R!9824 -28
Knob, Station Selector Rl9721D
Rubber foot
kit (4)
Rl9824 -29
Space r & Screw Kit
Rl9109 -36
Rl9726A TELEPHONE HANDSET ATTACHMENT
Receiver Unit Ul
Receiver Unit H
Al
H andset Co rd
H 4B4-3
N. E . • C , • 7 58
List
TOLER-
ANCE
~ %
MANUFACTURER OR 1YPE
N.E. Co.
20
20
20
20
20 Aerovox AFH 3004
Rogers
Majestic Cocp AC57
N.E. Co.
Mazda #47
National
Carbon Co.
11' 11 39B
10
10
10
30 N.
E. Co.
10
10
10
10
10
10
10
10
10
10
10 N.
E. Co.
N.E. Co.
N.E. co·.
N.E . Co.
N. E. Co.
Philmore Mfg. 2127B
Co. Inc.
Philmore
Mfg. 2127B
Co . Inc.
N. E.Co.
N.E . Co.
N.E. Co .
N.E.
Co.
N. E. Co.
N. E. Co.
N. E. Co.
N.E. Co.
National ltl
1398
Carbon Co.
N.E. Co .
N.E.
Co.
Pbilmore Mf g.
Co . Inc.
2127B
N.E. Co.
N.E. Co.
N. E. Co.
N.E. Co .
N.E . Co.
N.E•. Co.
N.E. Co.
N.E. Co·.
N.E. Co.
I
www.telephonecollectors.info ©Jef Lamb