Bogen 15-1 Service Manual

BOGEN

A DIVISION OF LEAR SIEGLER, INC.

MCT-1

SERIES 15

DESCRIPTION

The

Bogen

Series 15-1 Centralized School Sound
System is designed to serve up to 50 rooms. It incorpo­rates one Model MCT-1 Control Center and either one
or two Model SBS-25 Switchbanks, and is housed in a

desk-top consolette. The Series
to 25 rooms and includes one Control Center, one
Switchbank and one Model TP-160B AM/FM Tuner
housed in a desk-top consolette. The Series 15-2 consists
of one Control Center, one or two Switchbanks, one
AM/FM Tuner and one BSR 3-speed record changer. It
is housed in a desk-top, dual consolette and serves up to
50 rooms. The Series 15-3 consists of one Control
Center, one or two Switchbanks, one AM/FM Tuner
and one 3-speed record changer. It can accommodate up
to 50 rooms and is operated from a sturdy free-standing
console.

Each system has one 35-watt program channel and an
independent 4-watt intercom channel. The program
channel has two low-impedance microphone inputs
which can be used balanced or unbalanced. It also has
inputs for radio, phono and tape program sources and a
fader control to select either radio or phono-tape. The
selected program may be used alone or may be mixed
with the microphone program.

The MCT-1 control panel has a loudspeaker which
serves as both a program monitor speaker and an inter­com transmitter/receiver. By means of the intercom
channel, the operator may hold a two-way conversation
with occupants of any room without disturbing the pro­gram being transmitted to other rooms. If desired, the
intercom channel also may be used to permit the op­erator to monitor any selected room through its room
speaker.

15T-

1 accommodates up

MODELS

15T-1,15-2,15-3

Model 15-2

In addition to the control panel, each Series 15
solette or console has one or two switchbanks contain­ing the individual room selector switches. In the stan­dard system, these are 3-position lever switches used to
connect each room speaker to either the program (A)
channel or the intercom (C) channel, or to disconnect
the speaker from the system (Systems with optional
light-annunciator call circuit have four-position lever
switches). The units have an Emergency mode of opera­tion which overrides these selector switches. When
operating in Emergency, the operator can transmit from
the control panel speaker to all room speakers, regard­less of the settings of the room selector switches or of
other program inputs to the speakers. The Emergency
function operates whether the power switch is on or off.

INSTALLATION

UNPACKING

Inspect the shipping container and unit for indica­tions of improper handling. The unit was carefully
checked before leaving the factory. If the unit has been
damaged, make an
tributor from whom it was purchased. If the unit was
shipped to you, notify the transport company without
delay and place your claim.

immediate

claim to the dealer or dis-

15-1,

con-

Printed in USA

8005

CENTRALIZED SCHOOL SOUND SYSTEM

54-5665-04

LOCATION OF

CONSOLE/CONSOLETTE

Where possible locate the console centrally, relative
to the rooms being served, in order to minimize the
length of speaker cables. The rear of the unit must
remain accessible for maintenance and for changing in­put and output connections. It is advisable that the unit
be oriented in such a manner that the operator, program
director and other interested parties are able to observe
the controls at all times. Provide adequate lighting and
ventilation. Do not locate the unit close to heat sources,
such as radiators and warm-air ducts, or against a wall
which prevents proper ventilation.

The Series 15-1 and

15T-1

consolettes are 21¼” (54

cm.) wide x 16” (40.6 cm.) high x 16” deep. The Series

15-2 consolette is 40½” (102.9 cm.) wide x 16” high x
16” deep. The Series 15-3 console is 22” (55.9 cm.) wide

x 46” (116.8 cm.) high x 31” (78.7 cm.) deep.

POWER

Connect the 3-wire cord with ground to a

50/60

Hz source. Make certain that the ground terminal

of the power receptacle connects to earth ground.

Two 50W AC power receptacles are provided on the
rear panel for a tuner, automatic record changer or aux­iliary equipment. Line voltage is applied to these com­ponents when the consolette or console power switch is
on. Plug AC line cords into appropriate receptacle.

105-125V,

INPUT CONNECTIONS

MICROPHONE INPUTS. Two terminal strips on

the rear of the MCT-1 provide for two low impedance
balanced or unbalanced microphone inputs.
conductor shielded microphone cable should be used
(Bogen #l008

or equivalent). Connect shield to terminal

1.

Two-

TUNER/PHONO-TAPE INPUTS. Two jacks accept

single-conductor shielded cable.

TAPE RECORDER/BOOSTER AMP INPUT. Ac-

cepts a two-conductor shielded cable

(Bogen

BB 8450 or

equivalent).

INTERCOM CALL-IN LINE. Connect parallel lines

from station call-in switches with 2-conductor shielded

cable. Connect shield to terminal 3.

SWITCHBANK

CONNECTION. Eleven-pin plug
connects three shielded pairs plus annunciator wire
from a switchbank. Also accommodates three lines for
optional telephone system.

TIME CLOCK INPUT. Terminal strip connects a
single-circuit time clock, closing contacts to activate the
optional Model SST-l Module.

GENERAL WIRING

RUNNING CABLES

WIRES. Class II wiring may be used for all audio and
annunciator lines. Make certain to properly support
cables to prevent sagging or strain. Keep wires clear of
objects which would subject them to heat, friction, or
other abuse.

Use No. 20 AWG shielded pairs with insulated outer

jacket (Bogen BB-8450, or equivalent) for speaker lines.

Annunciator lines require a third wire, which usually is
No. 22 AWG insulated wire with red insulation (Belden
8937, or equivalent). The number and types of wires
running from each room to the consolette and running
inside the classroom depend upon the type of speaker
operation required. Consult Table I for the wires re­quired in your particular system.

TABLE I. CABLE RUNNING CHART FOR SERIES 15

Wires from Room to Consolette

Type of Classroom Switch or Device

Used with Speaker

None (Speaker Only)
Call (Model

CA-l0)
Call/Privacy (Model CA-l 1)
Voice Call-In, Non-Private

(Model CA13)

*Alternate method:

Run

two cables from room nearest consolette and one cable from each remaining room. Run

one cable in a loop or branch circuit connecting all room switches.

Shielded Pair

(Jacketed)

(Bogen

BB-8450)

1

1

1

2* 0

-2-

No. 22 AWG

Single

Conductor

(Belden

8937)

0
1 1
1 1

Wires From Room Switch

to Room Speaker

Shielded Pair

(Jacketed)

(Bogen BB-8450)

0

1

Refer to

Figure

2, 7

OUTLET BOXES. Where flush-mounting switches
are used, single-gang outlet boxes will be installed. In
installing such boxes, make certain to place them in a
location that permits personnel to operate the switch
while communicating via the room speaker. The normal
height (above the finished floor) for room switches is
approximately four feet, while speakers are normally
placed at a height of about seven and one-half feet.

CLASSROOM WIRING

CONNECTIONS

Refer to the left-hand column of Table I for the type
of classroom operation used in your system. The corres­ponding right-hand column calls out the wiring diagram
required. Solder the wires as shown in the proper dia­gram and wrap with insulating tape.

SOLDERING INSTRUCTIONS

SOLDER.
Make all solder connections with standard
core radio solder. Do not apply excessive heat. Solder­ing irons or guns from 75 to 200 watts will provide
ample capacity.

GROUNDS.

ground or to convenient metal objects.

connect cable shields only as shown in the wiring
diagrams.

SPEAKER TRANSFORMER

Do not use acid-core solder or acid paste.

60/40 resin-

Do not connect cable shields to earth

It

is important to

BOGEN

ROOM

25-VOLT

LINE MATCHING

(SEE NOTE-P)

CAUTION

Make certain to connect

all

wires in accor­dance with the color codes given on the dia­gram.

SECURING SWITCHES

The Model CA switches are designed for flush

mounting in a standard single-gang electrical outlet box,

BOGEN 25-VOLT

ROOM

SPEAKER TRANSFORMER

LINE MATCHING

(SEE

NOTE-2)

(SEE NOTE-I)

--

I

22AWG MIN.(TYP.)

(BELDEN 8937, OR

TO CONSOLE ‘SWITCH BANK

NOTES :
I- CONNECT AS FOR NON-PRIVATE OPERATION, AS FOR NON-PRIVATE WITH ANNUNCIATOR,

OR AS

2-

MODEL

AND ADDITIONAL INFORMATION.

FOR PRIVATE WITH ANNUNCIATOR.

TS-2A (1/2

--

EOUIV.)

WATT TAP) SHOWN.

SEE TEXT FOR

Figure 1 - Connection Diagram,

TS-I6A

Speaker

TRANSFORMER

Installation

-3-

TO CONSOLE

SWITCH BANK

74-2588-A

Figure 2 - Room Speakers with Voice Call-In Switch, Connection Diagram

LINE

or for surface mounting in a standard deep single-gang
wire mold outlet box. Install the box in a location which
provides convenient access to both the switch and the
room speaker.

LINEMATCHING TRANSFORMERS

The installation diagrams show
transformers of
or TS-05). Other recommended transformers are shown
in figure 3. The console output is designed for a
constant voltage distribution system and all system
loudspeakers must be provided with line-matching
transformers.

¼

or %-watt capacity (Models TS-025

Bogen

line-matching

25-volt

CAUTION

Speakers and transformers must be proper­ly matched with respect to power

require-

men ts.

CONSOLETTE WIRING

Remove the Phillips-head screws securing the

louvered pane1 on the rear of the consolette (or console).

There are three rows of solder terminals across the rear

of each switchbank. Each selector switch corresponds
to the three terminals directly behind it, one terminal
from each row.

White tabs are provided for identifying the room con­trolled by each selector switch. Insert the tabs in the
slots provided in the transparent switch knobs. When
rooms are identified by number, it is common practice
to start numbering the switches from left to right (view­ing from the front or operator position), starting with

the top switchbank.

SWITCHBANK WIRING

Wire the switchbanks as shown in figure 4. If annun­ciator lamps are used (Model SBL), always solder the
single annunciator wire to the top solder terminal. For
all switch banks, solder the speaker lines to the center
and bottom terminals, with the shield to the ground bus
bar.

This is the only place where speaker shields should

be grounded.

VOICE CALL-IN OPTION

Figure 2 shows the room connections and switch re­quired for installing an optional voice call-in system.
The wiring must be completed by connecting the
shielded pair from the switch to the terminal strip on the

rear of the MCT-1 chassis. The polarity of the inner
conductors is not critical, but make certain to connect
the cable shield to the shield of the cable already con-

nected to the terminal strip.

Note that only one cable goes to the terminal strip.

Usually, the cables from all room switches are con-

nected by a common control cable and one cable is run
to the consolette. If this type of installation is not prac­tical, then the control cables for two or more switches
are run to the consolette. In this case, connect all the
cables in parallel in a junction box at the consolette and
run a single control cable from the junction box to the
terminal strip on the MCT-1 chassis.

CALL/PRIVACY OPTION

Figure lc shows the room connections and switch

quired for installing an optional annunciator/privacy

function in the intercom system.

re-

4-

CONTROL FUNCTIONS

All operating controls for the Series 15 Centralized
School Sound Systems are located on the front of the
consolettes (consoles). The Series
with an AM/FM radio tuner, while the Series 15-2 and

15-3 have both a tuner and an automatic record chang­er. The operating controls for the tuner and record
changer are described in their individual instruction
manuals.

MCT-1 CONTROL PANEL

The controls on the Model MCT-1 Control Panel are:
POWER ON-OFF SWITCH. Turns the system on and
off.
FUNCTION SELECTOR SWITCHES. These switches
determine the mode of system operation. These operat­ing modes are:

1.

Microphone. Connects microphone input to program

channel (selected by MIC level control).

2.

Program. Permits transmission of program material

as determined by program distribution and program
output switches.

3.

Intercom. Enables and disables TALK/LISTEN

switch.

4. Emergency. Permits operator to transmit to all sta­tions via panel speaker, regardless of switchbank set­tings. Overrides all program and intercom functions.
Operates with power switch On or Off.

5.

Talk/Listen. Allows operator to communicate with

room(s) selected on switchbank without affecting pro­gram distribution to remaining rooms. Enabled by In­tercom switch; depress to talk, release to listen.

15T-1

is equipped

CONSOLE SWITCH BANK

TYPE SBL SWITCH

SHIELDED PAIR

(BOGEN

BB-8450, OR EOUIV.)

NOTES

I-TERMINALS CORRESPOND TO SWITCH ON OPPOSITE

SIDE OF FRONT PANEL.

2-DRESS SPEAKER LEADS TO PREVENT SHORTING

LOWER TERMINALS TO GROUND BUS.

Figure 4 - Consolette Switch Bank, Connection

Diagram

LEVEL CONTROL SWITCHES

1.

Microphone. Fader control sets level of Mic 1 or Mic

2 program as indicated on output meter. May be used
with Program level control for mixing.

25

VOLTS

TS

RED

TS-2A

TS -

16A

OHMS

8

ONDARY

SEC

RED

BLK/YEL

YEL
YEL

-

8

OHMS

SECONDARY

l/8 W
l/4

w

l/2

w

I w

2

W

Figure 3 -Bogen Line-Matching Transformers

TS-

POWER

TAP

w

2

4

w

8 w

16

W

16A

CENTER

TAP

WHT

ORN

ORN

-5-

2. Program. Fader control sets level of radio or

tape program as indicated on output meter. May be
used with Microphone level control for program
mixing.

3. Intercom. Sets outgoing level of intercom transmis­sion to room speakers.

4.

Monitor. Sets panel speaker level in program and

intercom modes.

5.

Tone. Provides flat response or reduces high-fre-

quency response as control is moved toward HI CUT.

PROGRAM OUTPUT METER. Color-coded to clearly
display 25 V reference level.

PROGRAM SWITCHES

1.

Program Distribution. Functions when program

output selector is in SEND.
vides switchbank control over program distribution.
ALL position distributes program to all rooms not con-

nected to the intercom.

2.

Program Output. SEND position enables program

distribution switch. SET position disconnects program
output from load for monitoring or presetting prior to

distribution. Does not offset intercom functions. The

program output switch should not be left in the SET
position. Once adjustment is made, switch should be

returned to SEND position.

NORM(a1)

position pro-

phono/

SWITCH BANKS

MODEL SBS SWITCHBANK. Standard consolettes
are equipped with one or two Model SBS Switchbanks.
Each switchbank has 25 three-position lever switches
for connecting individual rooms to the system. Each
switch functions as follows:

A - (Up position)

program channel for distribution of microphone, radio,
or phono program.

0

-

(Center position)

from system, except when consolette is operating in
Emergency mode.

-

(Down position)

C

intercom channel.

MODEL SBL SWITCHBANKS (OPTIONAL). If

the system is equipped with an optional light-annunci­ator call system, the consolette switchbanks will have
four-position lever switches. These switches operate
exactly as those in the Model SBS Switchbank, except
that there is a “B” (top) position of the switches which
is not used. If a switch is placed in the “B” position, it
functions exactly the same as in the “A” position.

-

Connects classroom speaker to

-

Disconnects classroom speaker

-

Connects classroom speaker to

OPERATION

NOTE

Before attempting to operate for the first
time after installation, check all input and
output connections and make certain the
consolette is connected to a power outlet.

TO TURN

Set POWER ON-OFF switch to ON position.

CONSOLETTE-ON

TO DISTRIBUTE MICROPHONE
PROGRAM

Move program output switch to SET position. De­press MIC function switch. Select microphone level with
MIC fader control knob according to
speaker volume and/or reading on PROGRAM LEVEL
output meter. When appropriate level is reached, dis­tribute program by moving program output switch to
SEND position. Select either NORM for Switchbank
control over distribution or ALL for distribution to all
stations not connected to the intercom. (May be used in
conjunction with PROGRAM level control for program
mixing).

contro1

panel

TO DISTRIBUTE RADIO/PHONO-TAPE

PROGRAM

Move program output switch to SET position. De­press PROG function switch. Select level of radio/

phono/tape

knob according to control panel speaker volume and/or

output meter reading. Distribute program by switching
program output to SEND position.

To distribute output from a tape recorder, connect
the 2-conductor phone plug from the tape recorder to
TAPE IN jack on the control panel and follow pro­cedure outlined above. Phonograph input will be auto­matically disconnected.

program with PROGRAM fader control

TO OPERATE ALL-CALL FUNCTION

Move program output switch to SEND position.
Move program distribution switch to ALL position.
Program is transmitted to all stations regardless of posi­tion of station selector switches. (Note: Disconnect in­tercom function; stations connected to the intercom will
not be affected).

TO COMMUNICATE WITH SELECTED
STATIONS

TO SEND. Depress INTERCOM function switch.
Select station to be contacted on switchbank panel.
Depress TALK/LIST switch to send; release switch to

monitor. Intercom level control should always be left at

the setting for normal transmission to room speakers.

(Note: does not affect program distribution to other
stations).

TO RECEIVE. If a voice call-in system is installed,

the station operator makes contact over the intercom
channel via the station speaker and CA-13 call switch,

and identifies his or her station. To respond to call,
select station on switchbank and depress TALK/LIST

-6-

switch. Speak clearly into the control panel speaker
from a distance of approximately 12” (Note: Intercom
function switch must be depressed to receive VOICE

CALL IN from stations).

TO OPERATE EMERGENCY

Depress

speaker. Message is transmitted to all stations regardless

of switchbank settings, program and intercom function

settings, and position of POWER ON-OFF switch.

EMERG

switch and speak clearly into panel

ACCESSORY EQUIPMENT

LIGHT-ANNUNCIATOR CALL SYSTEM

If a light-annunciator call-in function is installed, the
optional Model SBL Switchbank panels have an annun­ciator lamp above each station selector switch. Each sta­tion has a call switch to light the appropriate lamp.
When lamp lights, move the corresponding switch to
“C”

position. The intercom channel is now open for
normal intercom communication. The control panel
also has a built-in tone alert to provide audible annunci­ation that supplements switchbank lamps.

Figure 5 -Connecting Booster-Amplifier

PRIVACY FUNCTION

Prevents the console operator from monitoring the

speaker station if the station is provided with the op-

tional CA-l 1 CALL/PRIVACY Switch. A station in
the Privacy mode will still receive messages from the
consolette.

TIME TONE OPTION

The external single-circuit time clock closes contacts
that are normally open to activate the optional Time
Tone Module SST-l for timed, preset signals to station

speakers. Connects to terminal strip on the rear of the
control panel.

EXTERNAL BOOSTER AMPLIFIER

Model MT-60A or MT­increased power output. To install, remove the MCT-1
top cover and cut the jumpers on the terminal strip
between points A, B and C, D as shown in figure 5.

Insert two-conductor shielded cable in hole F. Connect

25 V balanced output leads to terminal strip points B

and C. Connect the shield to E. Attach the cable from

the Tape Out/Booster output jack on the rear of the

MCT-1

to the Hi-Z input of the MT-60A or MT-125B.

125B

(60 or 125 watts) provide

MAINTENANCE

CAUTION

There are no user-replaceable parts within
the unit. Have all in
qualified service personnel.

BOGEN SERVICE

We are interested in your
long as you have it. If trouble ever develops, do not
hesitate to ask our advice or assistance. Information can

be obtained by writing to Service Department,

Division, P.O. Box 500, Paramus, N.J. 07652.

When communicating with us, give the model and
series designation of your unit. Describe the difficulty
and include details on the electrical connections to asso­ciated equipment, and list such equipment. When we re-

ceive this information, we will send you service infor-

mation if the trouble appears to be simple. If the trouble

requires servicing, we shall send you the name and ad­dress of the nearest
which you can send your unit for repairs.

When shipping your unit, pack the amplifier well,
using the original shipping carton or a similar container
and filler material to prevent damage in transit. Send
the unit, fully insured and prepaid, via any responsible
carrier. The unit will be promptly repaired and returned
to you express collect.

ternal

servicing done by

Bogen

equipment for as

Bogen

authorized service agency to

Bogen

-7

TECHNICAL SPECIFICATIONS

Rated Output: Program: 35 Watts

Intercom:

Frequency
Response: Intercom:

Distortion:

Noise Level:

Sensitivity

Program:

articulation.

Less than 3% @

10.000 Hz
Microphone:

Radio/Phone:

:

Microphone: 300
Radio/Phone:
Tape In:

Intercom:

Inputs:

outputs:

Switches:

2 Microphones (Lo-Z, balanced or

unbalanced)

Radio
Phono
Tape In (Front Panel)

Program: 25 Volts balanced
Intercom: 25 Volts balanced
Tape Out/Booster: 2 Volts

Pushbutton Type: Microphone. Pro-

gram, Intercom, Emergency, and

Talk/Listen.
Program Send/Preset
Program Normal/All Call

Power On/Off

4 watts

100

to 20,000 Hz 2

Shaped for best voice

-50

-60

100 mV

100 mV

4

35

Watts:

dB

dB

µV

mV

100

dB

to

Controls:

Indicators:

Dimensions

(Inches

Finish:

Optional
Equipment:

&

Cm):

MCT-I Control Panel

Series

Series
Series

15-l (I5T-1)

Consolettes

15-2

Consolette

15-3

Console

Mic Volume (fader-MIC

Program Volume ( Radio/Phono-Tape
fader)
Intercom Level

Monitor

Tone Hi Cut/Flat

Illuminated output meter

Back and Sides-Satin Mocha
Control Panels-Desert Beige

Model SBL Switch Banks, for use

with visual and audible annunication.

Model SST­ule, for classroom change signals.

Room switches, for use with intercom:

l/MIC 2)

Width Height

5¼(

l9(48.3)

21¼(54)

40½( 102.9)

22(55.9)

Model CA-IO Call switch. Model
CA- I I Call/Privacy switch, Model
CA-13 Voice Call-In switch.

13.3) I

16(40.6) 16(40.6)
I6(40.6)

46(116.8)

1

A Single-Circuit Mod-

Depth

l½(29.2)

I6(40.6)

3 l(78.7)

ADJUSTMENTS

(For Qualified Service Personnel Only)

CAUTION

The follo wing adjustments require removal
of the top cover. Use standard precautions
to prevent electric shock or accidental short
circuits within the unit.

OUTPUT METER ADJUSTMENT

This is a factory adjustment that normally is not re­quired in the field. If a meter replacement is required, a
calibration adjustment may be needed. Proceed as

follows:

Feed a 1 kHz input signal in radio or phono jack.
Connect an A.C. V.T.V.M. across half the program
line (Pin 6 and 1 on output socket). With program
level control adjusted to read 12.5 volts on the
V.T.V.M., turn the meter control R102 (potenti­ometer nearest to front panel) until the needle reaches
the black mark on meter scale.

EMERGENCY LEVEL ADJUSTMENT

This is a factory adjustment that sets the emergency
output level the same as the intercom output level. If it
is necessary to adjust this level, turn the level control

RlOl

(potentiometer furthest from front panel) clock-

wise to increase output.

REPLACING COMPONENTS

All semiconductor components on the printed circuit

board are soldered in place to ensure maximum reliabil­ity. When soldering or unsoldering transistors or
diodes, use a heat sink (such as a small alligator clip)
between the component and the source of heat. When
replacing driver and output transistors (QlO-Qll), be
certain to install the collector insulator, after lightly
coating both sides with a thermal conducting compound
(such as Dow Corning No. 340, or equivalent).

REPLACEMENT PARTS

Most components used in
standard parts available through reputable parts deal­ers. This section lists those parts which should be re­placed with genuine
Bogen

distributors, service agency or directly from the

Bogen

factory.

When ordering a part, give the part number and de­scription as listed below. Specify the model of the unit.
For parts in the MCT-1 control chassis, specify the

series designation, which is a letter followed by numbers
and is stamped or screened on the rear of the chassis.

Bogen

equipment are

parts, available through

-8-

Fader control for
phono/tape program,as indicated on output
meter. Mav be used with
program mixing.

MIC LEVEL CONTROL
Fader control for setting level of Mic 1 or Mic 2
program as
used with PROGRAM level control for mixing.

MICROPHONE FUNCTION SWITCH
When IN, connects microphone input, selected
by MIC level control, to program channel.

PROGRAM FUNCTION SWITCH
When IN,
material as determined by program
and program output switches.

INTERCOM FUNCTION SWITCH
When

EMERGENCY SWITCH l
When IN. permits operator to
panel speaker) to all classrooms, regardless of
switch bank settings. Overrides all program and
intercom
POWER switch is OFF.

TALK/LIST(EN)
When enabled by INTERCOM function switch.
permits operator to communicate with
selected
gram distribution to remaining rooms.
Pressed for TALK; released for

indicated

permits transmission

IN, enables intercom Talk/Listen switch.

functions. Operates

on switch bank without effecting pro-

setting

level of radio or

MlC

level control for

on output meter. May be

ev en

SWITCH .

LIST(EN).

when

room

De-

Figure 6

__

-

Front view, MCT-1 Control Panel

PROGRAM OUTPUT M ER. Color coded to
clearly display 25V refe ce level.

SPEAKER. For program monitoring,

gency

transmissions,

communication.
POWER SWITCH. Controls ac power to panel

and to equipment connected to rear panel con­venience

outlets.

TONE ALERT (OPTIONAL). Provides audible
annunciation to supplement lamps on switch

l PROGRAM OUTPUT SWITCH. SEND position

enables program distribution switch. SET posi­tion disconnects program output from load for
monitoring or presetting prior to distribution.
Does not effect intercom functions.

l TAPE RECORDER INPUT. For playing output

from tape recorder on program channel. Ac­cepts

standard 2-conductor phone plug which,
when inserted, automatically disconnects phono­graph input.

two-way intercom

emer-

AC POWER INPUT
3-wire cord with

50/60

Hz source. Ci

panel andconvenience outlets.
CONVENIENCE OUTLETS

Each provides up to
or other auxiliary
front panel POWER switch.

TIME CLOCK INPUT .
For connecting external single-circuit time
clock. Clock closes normally open contacts to
activate optional Model SST-1A Module.

SWITCH BANK CONNECTION .
Cable terminated in
shielded pairs plus annunciator wire from
switch bank. Also accommodates three lines for

optional telephone system.

gr

equipme

Il-pin plug connects three

Figure 7

Rear view, MCT-1 Control Panel

-

MICROPHONE INPUTS. For low-impedance

balanced or unbalanced
microphone cable
nect

shield to terminal 1.

PHONO INPUT

TUNER INPUT

INTERCOM CALL-IN LINE. Parallel
classroom call-in switches. 2-conductor shielded
cable

(Bogen BB

shield to terminal 3.

l

TAPE RECORDER/BOOSTER INPUT. For recording
program material on external tape recorder and connecting
external booster
(Bogen BB

*Accepts Cinch 13A. or equivalent.

6450, or equiv.). Connect

amplifier 2-conductor

8450, or equiv.).’

mics.

(Bogen

Use 2-conductor

1006. or equiv.). Con-

Single-conductor
shielded cable.*

lines

from

shielded cable

Schematic

Reference

Part No.

Description

Schematic
Reference

Part No.

Description

Al
C3A,

4A
3B, 4B, 12
C7A, 7B
c17, 20, 28
C23
C26
C27
CR-I, 2

IC1
Ql-7

Q-8

Q-9
Q-IO

Q-11

Q12

R30, 35

R39

2

S-l

Cl02

Cl03

Cl05
Cl06
Cl07
CBlOl
CB102
CR101
CR102
CR103-106

45-9995-01
79-008-03 1

79-008-o 11
79-008-053
79-008-045
79-008-030
79-008-049

96-53373-O 1
96-5396-O 1
96-5213-01
96-5346-O 1
96-5298-01
%-5283-O 1
96-5357-O 1

96-5356-O 1
96-5290-o 1
76-107-105
76-

147-087

45-9996-01 P.C. Board Assy.
96-5333-01
81-004-077 P.B. Switch w/knobs

Chassis Electrical Parts

79-509-050

79-009-070
79-009-052

79-005-050
79-509-O 14
94-00 17-04
94-00 14-04
96-5202-01
96-5333-01
96-5241-01

P.C. Board Assy, Amp.

Capacitor, Electrolytic,

l0µF,

16V
Cap., Electrolytic,
Cap.,

Electro.,

Cap.,

Electro., 330µF,

Cap.,

Electro.,

Cap.,

Electro., 500µF,
Diode, 400 piv,
Integrated

Transistor, 2N5089 or
Transistor, BC 239C
Transistor, SPS-l910
Transistor,
Transistor, 2SD-389 (P)
Transistor, 2SB 512 (P)

Transistor, MPS-A05

Resistor,

Resistor,

Switching

Diode, 400 piv,

Capacitor, Electrolytic,

1500µF, 75V

Cap., Electrolytic,

75v
Cap.,
Cap.,
Cap.,
Circuit Breaker, .93A

Thermal Breaker
Triple Diode, HVR-3
Diode, 400 piv,
Diode, 300 piv, 3A

Circuit; TBA

MPS-A5

4.7R,
lR, ½W

Electro, 22OOµF,
Electro.,
Electro.,

500µF, 50V

lOOµF, 35V

lOOµF,

1A

2W

1A

lOOµF, 25V

1A

330µF,

25V
35V

500µF,

35V

3V

1OV

800

PL-101

Q101-102

RlOl,
R103, 104

R105, 106
R107

Rl10

R114
R118
Ml01
KlOl
SPlOl
SWlOl-103

TlOl

­T103

T104

T105

YlOl

-

-

-

-

-

-

102

94-o 197-O 1
96-5232-02
77-00 l-576
77-00 l-763

77-00 l-762

77-00 l-76 1

76-

113-099
75-742-25 1
75-742- 100
94-1097-O 1
90-0037-O 1
93-0047-01
8 I-003-022
45-702 1-O 1

45-9999-o 1

83-449-000

45-9998-O 1

94-1361-01

03-0590-O 1

81-005-035

81-005-036 Lever Switch

94-0221-07 Pilot Light (SBL-25)
94-0310-03 P.L. Cap (SBL-25)
03-0550-O 1

82-2254-01 Cable Assy
82-2246-O 1

Pilot lamp, # 19
Transistor
Control, Level Adj.,
Control, Mic./Prog.

Volume, 1 M

Control, Intercom/Tone,

½M

Control,

200R
Resistor,
Resistor,
Resistor,
Meter w/mounting bracket
Relay
Speaker,
Switch, Slide, DPDT, 3A
Transformer, Power

(83-759-c-O)
Transformer, Intercom

Output (83-428-000)

Transformer, Intercom

output

Transformer, Intercom

Input (83-054-000)
Sonalert
Knob

Switchbanks

Lever Switch Assy (SBS-25)

Knob

Cabinet Parts

“J”

Cable Assy

-

Monitor/Emerg.

,27R, 5W

250R,

7W

lOOR,

7W

3½“,

45R

Assy.

(SB/SBL-25)

5R

Figure 8

Output Cable

-

-lO-

CONTROL FUNCTIONS

All operating controls for the Series 15 Centralized

School Sound Systems are located on the front of the

consolettes (consoles). The Series

with an AM/FM radio tuner, while the Series 15-2 and

15-3

have both a tuner and an automatic record chang­er. The operating controls for the tuner and record
changer are described in their individual instruction
manuals.

MCT-1

The controls on the Model MCT-1 Control Panel are:
POWER ON-OFF SWITCH. Turns the system on and
off.
FUNCTION SELECTOR SWITCHES. These switches
determine the mode of system operation. These operat­ing modes are:

1.

channel (selected by MIC level control).

2.

Program. Permits transmission of program material

as determined by program distribution and program
output switches.

3.
switch.

4. Emergency. Permits operator to transmit to all sta­tions via panel speaker, regardless of switchbank set­tings. Overrides
Operates with power switch On or Off.

5. Talk/Listen. Allows operator to communicate with

room(s) selected on switchbank without affecting pro-

gram distribution to remaining rooms. Enabled by In-

tercom switch; depress to talk, release to listen.

Figure 4 - Consolette Switch Bank, Connection

LEVEL CONTROL SWITCHES

1. Microphone. Fader control sets level of Mic 1 or Mic
2 program as indicated on output meter. May be used
with Program level control for mixing.

CONTROL PANEL

Microphone. Connects microphone input to program

Intercom. Enables and disables TALK/LISTEN

all

program and intercom functions.

Diagram

15T-1

is equipped

2. Program. Fader control sets level of radio or

tape program as indicated on output meter. May be
used with Microphone level control for program

mixing.

3. Intercom. Sets outgoing level of intercom transmis­sion to room speakers.

4.

Monitor. Sets panel speaker level in program and

intercom modes.

5.

Tone. Provides flat response or reduces high-fre-

quency response as control is moved toward HI CUT.

PROGRAM OUTPUT METER. Color-coded to clearly
display 25 V reference level.

PROGRAM SWITCHES

I. Program Distribution. Functions when program
output selector is in SEND. NORM(al) position pro­vides switchbank control over program distribution.
ALL position distributes program to all rooms not con­nected to the intercom.

2. Program Output. SEND position enables program
distribution switch. SET position disconnects program

output from load for monitoring or presetting prior to

distribution. Does not offset intercom functions. The

program output switch should not be
position. Once adjustment is made, switch should be

returned to SEND position.

left

phono/

in the SET

SWITCH BANKS

MODEL SBS SWITCHBANK. Standard consolettes
are equipped with one or two Model SBS Switchbanks.
Each switchbank has 25 three-position lever switches

for connecting individual rooms to the system. Each
switch functions as follows:

A

-

(Up position)

program channel for distribution of microphone, radio,
or phono program.

0

-

(Center position) - Disconnects classroom speaker
from system, except when consolette is operating in
Emergency mode.

C

-

(Down position) - Connects classroom speaker to

intercom channel.

-

Connects classroom speaker to

MODEL SBL SWITCHBANKS (OPTIONAL). If
the system is equipped with an optional light-annunci­ator call system, the consolette switchbanks will have
four-position lever switches. These switches operate
exactly as those in the Model SBS Switchbank, except
that there is a “B” (top) position of the switches which
is not used. If a switch is placed in the “B” position, it
functions exactly the same as in the “A” position.

OPERATION

NOTE

Before attempting to operate for the first

time after installation, check
output connections and make certain the
consolette

is

connected to a power outlet.

all

input and

TO TURN CONSOLETTE ON
Set

POWER ON-OFF switch to ON position.

DISTRIBUTE MICROPHONE

PROGRAM

Move

press MIC function switch. Select microphone level with
MIC fader control knob according to control panel
speaker volume and/or reading on PROGRAM LEVEL
output meter. When appropriate level is reached, dis­tribute program by moving program output switch to
SEND position. Select either NORM for Switchbank
control over distribution or ALL for distribution to all
stations not connected to the intercom. (May be used in
conjunction with PROGRAM level control for program
mixing).

program output switch to SET position. De-

TO DISTRIBUTE RADIO/PHONO-TAPE
PROGRAM

Move program output switch to SET position. De­press PROG function switch. Select level of radio/
phono/tape

knob according to control panel speaker volume and/or
output meter reading. Distribute program by switching

program output to SEND position.

To distribute output from a tape recorder, connect
the 2-conductor phone plug from the tape recorder to

PE

re outlined above. Phonograph input will be auto-

matically disconnected.

program with PROGRAM fader control

IN jack on the control panel and follow

pro-

switch. Speak clearly into the control panel speaker
from a distance of approximately 12”
function switch must be depressed to receive VOICE

CALL

IN

from stations).

(Note:

Intercom

TO OPERATE EMERGENCY

Depress

speaker. Message is transmitted to all stations regardless
of switchbank settings, program and intercom function
settings, and position of POWER ON-OFF switch.

EMERG

switch and speak clearly into panel

TO OPERATE ALL-CALL FUNCTION

Move program output switch to SEND position.
Move program distribution switch to ALL position.
Program is transmitted to all stations regardless of posi­tion of station selector switches. (Note: Disconnect in­tercom function; stations connected to the intercom will
not be affected).

TO COMMUNICATE WITH SELECTED
STATIONS

TO SEND. Depress INTERCOM function switch.
Select station to be contacted on switchbank panel.
Depress TALK/LIST switch to send; release switch to
monitor.

the setting for normal transmission to room speakers.

(Note: does not affect program distribution to other
stations).

the station operator makes contact over the intercom

Intercom level control should always be left at

TO RECEIVE. If a voice call-in system is installed,

annel via the station speaker and CA-13 call switch,

identifies his or her station. To respond to call,

station on switchbank and depress TALK/LIST