Continental Electronics 212P-2 User manual

r
TYPE 212P-2/212P-1
III
AUDIO CONSOLES
111
INSTRUCTION MANUAL
80*1432
t / f t p h t /j f m f ! *> r fJ umJLC-A
e. BLJCKf\UEJ=t BUi/D.
MFG. OO.
DALLAS, TEXAS 7C22T
1 OCTOBER 1980

CONTINENTAL ELECTRONICS MFG . CO.
P.O. BOX 270879
DALLAS , TEXAS 75227
214/ 81-7161
Telephone :
Telex: 7 - 98
t
FOR 24 HOUR PROFESSIONAL SERVICE
214/ 27-45 2 FOR PARTS
214/ 27-45 FOR SERVICE
CALL:
CALL:

?1 2P — 1/2
table of contents /
Page
1-1
Section 1 General Description
1-1
Introduction ..............
Equipment Purpose ----
Physical Description .
Functional Description
1.1
1-7
1.2 1-7
1.
1-7
1.4
2-1
Section 2 Installation
2-1
Unpacking and Inspection .........................
Installation Procedure ........................... .
General ................................................ .
Input Connections ............................... .
Wiring Methods ....................................
Grounding .............................................
Power Supply Installation .................
Phasing of Audio Circuits .................
High Level Input Connections ............
Connection of Monaural Sources .........
Microphone and Muting Connections ...
Warning Light Connections .................
Loudspeaker Connections .....................
Program Line Connections ...................
Air Monitor Connections .....................
Machine Control Interface Connections
Special Circuit Connections ...................
Special Microphone Effects ...............
Use of Auxiliary Inputs and Outputs .
Monaural Output ..................................
2.1 2-1
2.2
2-1
2.2.1
2.2.2
2.2.
2.2.4
2.2.5
2.2.6
2.2.7
2.2.8
2.2.9
2.2.10
2.2.11
2.2.12
2.2.1
2.2.14
2-1
2-
2-4
2-4
2-4
2-5
2-8
2-10
2-1
2-14
2-15
t
2-17
2-17
2-20
2. 2-20
2. .1
2. .2
2. .
2-20
2-22
Section Operation
-1
Control Functions .........................................................
Mixers .......................................................................
Input Selector Switches .........................................
Monitor and Headphone Lever Controls ...................
Monitor and Headphone Assignment Switches ...........
Channel 7B and Channel 8B Input Selectors ...........
Operating Procedures ....................................................
Routine Operation ....................................................
Local Program on the Air .................................
Cueing Turntables or Other Material ..............
Removal of Program Material From the Air ___
.1
-1
.1.1
.1.2
.1.
.1.4
.1.5
-1
-1
-1
-1
-2
.2
-2
.2.1
.2.1.1
.2.1.2
.2.1.
-2
-2
-2
-2
iii

21 2P-1/2
table of contents (cont)
I
#
Page
4-1
Section 4 Principles of Operation
4-1
General ...................................................
Mixer Circuits .......................................
Program Circuits ....................................
General ............................................
Mixer Amplifier ...............................
Program Output Amplifier ...............
Power Supply ....................................
Monitor Circuits ....................................
General ............................................
Monitor/Headphone Function Selector
Monitor Output Amplifier ...............
Headphone Output Amplifier ............
Cue Amplifier/Regulator .................
Power Supply ....................................
Cueing Circuits ......................................
General ............................................
Cue Amplifier ..................................
Cue Amplifier/Regulator .................
Microphone Amplifier .............................
Power Supply ...........................................
Machine Control Interface .....................
4.1
4-1
4.2 4-7
4.
4-7
4. .1
4. .2
4. .
4. .4
4-7
4-9
4-9
4-9
4.4 4-9
4.4.1
4.4.2
4.4.
4.4.4
4.4.5
4.4.6
4-1
4-1
4-14
4-14
4-14
4-15
4.5
4-15
4.5.1
4.5.2
4.5.
4-15
4-15
4-17
4.6
4-17
4.7
4-18
4.8
5-1
Section 5 Maintenance
Periodic Inspections and Preventive Maintenance
Attenuators ...................................................
Wiring ............................................................
Replacement of Switches ......................................
Input Selector Switches ...............................
Channel 7B and 8B Selector Switches ..........
Channel Control Switches .............................
Replacement of Attenuator ..................................
Removal of Amplifier Modules . .............................
Microphone Preamp and Mixer Amplifier .......
Output Amplifier . . .........................................
Extender Card Installation .................................
Output Amplifier Gain Settings ..........................
Section 6 Parts List ..........................................................
5-1
5.1
5.1.1
5.1.2
5-1
5-1
5.2 5-1
5.2.1
5.2.2
5.2.
5-1
5-1
5-2
5.
5-2
5.4
5-2
5.4.1
5.4.2
5-2
5-2
5.5
5-4
5.6 5-4
6-1
6.1
General
6-1
Section 7 Diagrams 7-1
7.1
Introduction
7-1
iv

2.1 2P-1/2
li t of illu tration '
t
Figure
Page
1-2
1-1
212P-1 Monaural Audio Console ..................................
212P-2 Stereophonic Audio Console ............................
Interior View 212P-2 Stereophonic Console ..............
Power Supply ...............................................................
Machine Control Interface .........................................
Outline Drawing ..........................................................
Wire Preparation .........................................................
Attenuator Network .....................................................
Dividing Network .........................................................
Input Connections for Channels 7B & 8B ...................
Microphone Connections ..............................................
Muting Connections for Multiple Microphones ..........
External Microphone Mixer Connections .....................
Loudspeaker Muting Connections .................................
Warning Light Relay Connections ...............................
Single Loudspeaker Connections .................................
Transformer Schematic ................................................
Multiple Loudspeaker Connections .............................
Typical Machine Control Connections ........................
Special Microphone Circuit Connections ...................
Reverb System Connections .........................................
Telephone Interface Connections Transmit Circuit ..
Telephone Interface Connections Receive Circuit ...
Monaural Combining Networks ......................................
Block Diagram 21 2P- ( ) Audio Console .....................
Simplified Schematic, Typical Input Channel 1-6 ----
Simplified Schematic, Input Channels 7&8 ................
Simplified Schematic, Program Output Circuits .......
Simplified Schematic, Monitor Output Circuits .......
Simplified
Schematic, Cue Circuits ..........................
Simplified Schematic, Microphone Preamplifier .......
Schematic Diagram Power Supply .................................
Machine Control Interface Unit .................................
Simplified Schematic, Machine Control Interface ...
Switch Rear View .........................................................
Switch Connections .....................................................
Output Module Gain Setting & Fusing Information ...
Picture of Console with Extender Card in Place ----
Microphone Preamplifier, Schematic ..........................
Mixer Amplifier, Schematic ........................................
Output Amplifier, Schematic ......................................
Cue Amplifier, Schematic ...........................................
Cue Preamplifier , Schematic ....................................
Power Supply, Schematic .......... . .................... . ..........
Headphone/Monitor Assignment Switch, Schematic ....
Input
Term Board CH 1 - 6, Shematic ........................
1-2
1-
1-4
1- 1-5
1-4
1-6
1-5
2-2
2-1
2-
2-2 2-6
2-
2-8
2-4
2-9
2-5
2-10
2-6
2-11
2-7
2-12
2-8
2-12
2-9
2-1
2-10 2-14
2-11
2-15
2-12
2-16
2-1 2-19
2-14
2-20
2-15
t
2-21
2-16
2-21
2-1 7A
2-17B
2-22
2-2
2-18
4-
4-1
4-5
4-2
4-6
4- 4-8
4-4
4-11
4-5 4-16
4-6 4-17
4-7
4-18
4-8
4-19
4-9
4-21
4-10
5-
5-1
5-
5-2
5-4
5- 5-5
5-4
7-2
7-1
7-
7-2
7-5
7-
7-7
7-4
7-9
7-5
7-10
7-6
7-11
7-7
7-12
7-8
v

2l2l > -l/2
1 i t of illu tration (cont)
i
Page
Input Term Board CH 7 - 8, Schematic .........
Channel 7B/8B Input Switch Card, Schematic
Machine Control, Schematic ..........................
Front Panel, Schematic, Sheet 1 of 2 ........
Front Panel, Schematic, Sheet 2 of 2 .........
Interconnect
Cabling & Backplane, Schematic
7-1
7-9 7-14
7-10 7-15
7-11
7-17
7-12
7-19
7-1
7-20
7-14
list of tables
Page
Table
212P-(^) Physical and Electrical Characteristics ...
Attenuator Networks .....................................................
External Connections,Channel Input Terminal Boards .
External Connections,Backplane Terminal Boards .......
1-8
1-1
2-7
2-1
2-24
2-2
2-25
2-
list of drawings
Page
Drawing
6-
Monaural Console Assy ........................
Stereo Console Assy ............................
Base Assy .............................................
Cue Amp Bd Assy ...................................
Output Amp Bd Assy .............................
Mixer Bd Assy, Channels 1 - 5 ..........
Channels 7-8 Input Select Bd Assy .
Headphone/Monitor Bd Assy .................
Channels 7B & 8B Input Switch Bd Assy
Control Panel Assy .............................
Mixer Bd Assy, Channels 6 - 8 ..........
Backplane Bd Assy ...............................
MIC Amp & Mixer Amy Bd Assy ..............
Channel 1 Input Switch Bd Assy .........
Attenuator Assy ...................................
Channel Input Bd Assy ........................
Channels 7 & 8 Input Terminal Bd Assy
Power Supply Assy ...............................
Card Extender Assy .............................
Cue Preamp Bd Assy .............................
Machine Control Assy ..........................
Machine Control Bd Assy .....................
622- 646
622- 647
6 6-5571
6 6-5576
6 6-5579
6 6-5582
6 6-5585
6 6-5588
6 6-5591
6 6-5594
6 6-5602
6 6-5610
6 6-561
6 6-5625
6 6-56 2
6 6-56 9
6 6-5642
6 6-565
6 6-566
6 6-5668
6 6-5274
6 6-5278
6-7
6-11
6-15
6-19
6-2
6-27
6-29
6- 1
6-
6-41
6-45
6-47
6-51
6-5
6-55
6-57
6-59
6-6
6-65
6-67
6-69
vi

212P-1/2
ection 1
general de cription
SECTION 1
1.1
introduction
This instruction book contains all information necessary to install,
operate, maintain, and service both the 212P-1 Monaural Audio Console
and the 212P-2 Stereo Audio Console. Figure 1-1 depicts the external
configuration of the Monaural Console; figure 1-2 shows the stereo con 
sole; figure 1- shows the internal make-up of the 212P-2 Stereo Audio
Console; figure 1-4 is the console power supply; and figure 1-5 shows
the optional machine control interface assembly. The sections of this
instruction book provide the following classes of information for each
of these types of audio console.
a. Section 1, GENERAL DESCRIPTION, provides a description of the equip 
ment, identifies the major components, lists physical and electrical
characteristics , and describes the options.
b. Section 2, INSTALLATION, provides information relative to incoming
inspection, input/output connections, initial adjustments, and wiring
instructions .
Section , OPERATION, identifies and describes the functions of panel
and component mounted controls and indicators, and provides informa 
tion necessary to set up and operate the console.
Section 4, PRINCIPLES OF OPERATION, provides descriptions of funcion-
al circuits within the console, beginning with a general discussion
of the overall operation of the console and proceeding to a descrip 
tion of the function and operation of each circuit board.
Section 5, MAINTENANCE, describes procedures for preventive and
corrective maintenance, with suggested performance schedules.
Section 6, PARTS LIST, provides information for ordering replacement
components and assemblies, and parts location illustrations for each
major assembly and each circuit board.
Section 7, DIAGRAMS, contains schematic and wiring diagrams required
for console maintenance.
c.
t
d.
e.
f.
g-
t
1-1
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

0^

212P-1/2
general de cription
4
it Mi
# ;
*
Figure 1-2. 212P-2 Stereophonic Audio Con ole.
1-3
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212P-1/2
general de cription
t-
it
•'•■ "I
.• -J
III
■: :l l
tih { A
:- V
:!
:
HR
| pp ; s^i
imm
| E l MD£
Interior view 212P-2 Stereophonic Con ole.
Figure 1-3.
i
1-4
DISCONNECT PRIMARY POWER BEFORE SERVICING.
WARNING:

212 P — 1/2
general de cription
■ ' ■ • / i
\
&
i
WSM&M33M
c,:1
3
rnrnmmmmm:
: 'C- j
|i|aiabldbidbBS>a@Balia*^
fTTnTnx 1 4
; i ,3K:S
•^j
‘
;■ '
S SSil|ltiI|5
flkaaR .
Cr
■?■
r
m
: :
•' ;>';j
■~7
li-M:
'•
* • ; • ’ , :
• ’
te I -
mm :
' Tf
:>l
dur
r/-
[C m
1MSS
a
■£ *;;•
IS!
I
j
1
a?
if
J k
n
K
o
t
■ •
m
rt
2.«
-a
o
ll
Si
mm
MI
M
it
st®
x; trf*
■3
<
■.:V;
%
II
KM
■ Ini
Si
Wm
m
<n
M
o--i-i
£
litwHilsML
pjjSiS
'd ^o^s & i y i* i ™
mamma
m
W
f-f-;.- HU
M-l
I#
II-
||i
3»
a§
Up
c
H
*0
'HR
m
£
m
i
*
m
if
*P
i:;S
1
wmM-
:- ,m
II
ll-i:
l 4
Figure 1-5. Machine Control Interface.
1-6
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212P-1/2
general description
ppg ; : gllgfgitp
|&U J
Sjr v '
liSSsISIil
Mt g i«ii r
i piSjSI
fe a
*
;
ft
.'"V
; '-g
bi
■
1&
s
fc:
*foy
.-.
i
w
i
m
,fe>
;v
v ; 5
*
>a
W*
Figure 1-4. Power upply.
1-5
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212P-1/2
general de cription
1.2
EQUIPMENT PURPOSE
The audio console is used to mix, control, and monitor audio sources in
broadcast service.
It also provides cueing facilities on all channels.
An (optional) associated machine control interface unit may be used to
start and stop audio sources such as tape machines and turntables under
control of the console switches.
1.
PHYSICAL DESCRIPTION
The console is housed in a cabinet designed for desk top mounting. The
cabinet
is painted with a gray, light diffusing, abrasion resistive
paint. The front panel is white, with plastic finished silk screening;
and the switches, knobs, and meter(s) are color coordinated. The cabinet
is approximately 228.6mm (9 in.) high, 86 ,6mm ( 4 in.) wide, and 482.6mm
(19 in.) deep. The front panel is hinged at the bottom to allow easy
access to the console interior.
The optional machine control interface unit is housed in a metal enclosure
9 .7mm (15.5 in.) long, 228.6mm (9in.) wide, and 6 .5mm (2.5 in.) high,
designed to be mounted in a desk or turntable cabinet.
FUNCTIONAL DESCRIPTION
1.4
t
The audio console contains all required mixers, amplifiers, program mon 
itoring, cueing, and switching circuits. An external power supply
provides required dc voltages to the various components of the console,
and machine control unit when this is used. The circuitry is hybrid in
design, employing both discrete and monolithic components. Circuits are
mounted on glass fiber printed circuit cards. All operating controls are
conveniently arranged on the front panel.
There are eight mixer circuits, each with the capability of selecting one
of two inputs. Each channel input select switch 1 through 6 can select
one of two audio sources to apply to its associated mixer; and each chan 
nel input select switch 7 and 8 can select either one direct source or
any one of six indirect sources. Any number from one through eight of up
to 26 available source signals can be mixed for simultaneous application
to the program circuits.
The outputs of the mixer switches are applied to the program buss. In
the mono console, a single program buss produces mono signals. In the
stero console, the left and right outputs of the mixer switches are
applied to two program busses (left and right) to produce stereo signals.
The (mono or stereo) signals are then amplified, adjusted in level, and
applied to the program output line(s). The output level is monitored:
in the mono console, by a single VU meter; and in the stereo console, by
two VU meters, one for the left program output, the other for the right
program output. The VU meters are used in adjusting the output level
and (in the stereo console) the output balance. Other front panel con 
trols enable connection of program monitor or air monitor, to the speakers
and program, air monitor or cue to the headphones.
1-7
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212 P — 1/2
general description
An optional machine control interface unit can be used to start and stop
audio sources such as tape machines and turntables. Up to twelve
machines can be controlled through this unit from switches on the audio
console.
212P-0/2) Physical and Electrical Characteristics.
Table 1-1.
ITEM
CHARACTERISTICS
1. SIZE
22mm (8.75 in. ) high
86.4mm ( 4 in.) wide
47.6mm (18.75 in.) deep
29.9kg (66 lb)
2. WEIGHT
Service Conditions
a. Ambient Temperature
b. Relative Humidity
c. Altitude
d. Vibration and Shock
.
0° to 50°C ( 2° to 1 22°F)
0 to 95% (without condensation)
0 to 4572 m (0 to 15000 ft)
Normal transportation and handling
Power Requirements
a. Voltage
b. Frequency
c. Power
4.
105 to 125 volt , or 210 to 250 volt , ac
50/60 Hz
150 watts maximum
Specifications
a. Input Levels:
Microphones
High Level
Air Monitor
Post Mix
b. Input Impedances:
5.
-50dBm nominal
0 dBm nominal
0 dBm nominal
+10 dBm
(All balanced, transformer coupled except Post
Mix input)
150 ohms
150/600 ohms
600 ohms
600 ohms
Microphones
High Level
Air Monitor
Post Mix
Output Levels
Program
Headphone
Monitor
c.
+18 dBm nominal; + 0 dBm maximum
5 watts nominal; 25 watts maximum into 8 ohms
25 watts maximum into 8 ohms'
25 watts maximum into 8 ohms
0 dBm into 600 ohms
Cue
Post Mix Output
Load Impedances
Program
Monitor
Headphone
d.
600 ohms
Not less than 8 ohms
Not less than 8 ohns
Not less than 8 ohms
Cue
1-8
PRIMARY POWER BEFORE SERVICING.
WARNING:
QISC0NNECT

212P-1/2
general description
Table 1-1. 212P-(l/2) Phy ical and Electrical Characteri tic (Cont)
ITEM CHARACTERISTICS
e. Noise: Program circuits
High Level Inputs
Microphone Inputs
f. Frequency Response
g. Distortion
75dB below +18 dBm
-125 dBm EIN (equivalent input noise)
+0.5 dB, 50 Hz to 15 kHz, all circuits
0.25% IMD (intermodulation distortion)
all circuits at nominal levels (SMPTE
method)
0.25% THD (total harmonic distortion),
all circuits at nominal levels.
•1-9
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212P-1/2
ection 2 /
in tallation
SECTION 2
INSTALLATION
2.1
UNPACKING AND INSPECTION
Remove all packing material, and carefully lift the units from their
boxes. Check the equipment against the packing slips. Visually inspect
the units for any apparent damage and for missing components. Check
for proper operation of controls. Any claims for damage should be filed
promptly with the transportation agency. If such claims are to be filed,
all packing material must be retained.
2.2
INSTALLATION PROCEDURE
2.2.1
GENERAL
The console location will be determined by the arrangement of the control
room facilities. In general, the console should be centrally located
among the source equipment to which it is connected. Frequently used
sources such as turntables and cartridge tape playback equipment should
be located close to the console for maximum operator convenience. Less
frequently used equipment, such as reel to reel tape machines, may be lo 
cated farther away from the console.
The rear of the console may be placed within 1/2 inch of a window or wall
if necessary since no rear access is required. The console need not be
bolted or otherwise secured to the top of the table. All connecting
cables enter through the bottom of the unit. Outline and mounting dimen 
sions of the console are shown in Figure 2-1. It is recommended that
1 inch diameter holes be drilled in the table for cable entry.
INPUT CONNECTIONS
2.2.2
The mixers should be assigned in such a manner as to provide maximum
flexibility for the operator. In general, each source used in the hourly
rotation sequence should appear on a separate mixer. For example, let's
assume that the control room plant consists of one control microphone,
one newsroom microphone, two turntables, three cartridge playback machines,
a network, a remote pickup radio system and two remote lines. Of these
sources, the following are used repeatedly in the hourly rotation:
control room microphone, newsroom microphone, two turntables, three car 
tridge playback machines and the network line. A logical arrangement
would be as follows:
Mixer
Control
Room Microphone
Newsroom Microphone
Turntable
1
Turntable
2
Cartridge Tape 1
Cartridge Tape 2
Cartridge Tape
Network Line
1A
2A
A
4A
5A
6A
7A
8A
2-1
DISCONNECT PRIMARY POWER BEFORE SERVICING.
WARNING:

2] 2P-1/2
I
in tallation
</)
LU
^*0
*4 OJ
-*0
*_
D
« ^ a 2
^ °A
^8
b Q CL OJ
, n - > tt
6
*
-4- -*•
VibS
i_
rO
*
C 3 5
Vi fi
i !
'iMCO f 4^!
i I
CM
I
1
■t
C3j^3-
I
<£
y
i
h
.2
' + »-
2
2
r^r
IP
~-F )
0
o
t
*
v9
ID
H
C X
m
Hi£
3
LL
r~Tfv ■> i
0
cr> 'T
&
OJ
i
CL
(0
I
vD
a
----------------------- «■+■> —
IU
I V
C3|E
'an co
I m
— i-c
c_-c£b=->
in
— Ixj- *
i
1
OJ
f
M*
(NJ Hi ----- 1^-*.
cO
irl-q.
Outline Drawing.
Figure 2-1.
2-2
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212P-1/2
/
in tallation
All normally used sources appear on separate inputs requiring no routine
switching operations for input selection. The remaining sources would be
connected as follows:
Reel to Reel 1
Reel to Reel 2
Remote Pick-up System
Remote 1
Remote 2
3B
4B
5B
7/8B-1
7/8B-2
The occasional use circuits would be assigned to the "B" inputs of each
mixer requiring only a simple pushbutton operation to air such a source.
2.2.
WIRING METHODS
All microphone wiring should be dressed away from the medium level wiring
associated with the balance of the console.
All wiring should be twisted pair shielded wire. For monaural circuits
or stereo circuits which require separate connectors for left and right
channels, a single twisted pair cable such as Belden 8451 or equivalent
should be used. For stereo circuits terminating in a single connector
or terminal board, a double twisted pair cable such as Belden 872 or
equivalent should be used. The shield should be grounded at the console
end only with the other end left unterminated. A separate ground of #18
AWG stranded wire should be run from the source equipment to the console
ground lug adjacent to the input connection.
The console end of all wiring should be terminated in an insulated spade
lug suitable for a #6 screw. Vaco stock number 54206 or equivalent is a
suitable lug for use with this console. A little extra time spent in
proper planning and execution of the console wiring will pay great divi 
dends in trouble-free future operation and reduced maintenance of the
console. Figure 2-2 shows how to prepare and terminate the wiring.
t
2-
Figure 2.2. Wire Preparation.
2-
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212P-1/2
I
in tallation
1)
Strip outer insulation sheath back 2 inches from the
cable end.
Strip each conductor insulation back 1/4 inch from wire
end.
Place a 1- /4 inch length of spaghetti over the drain
wire.
Place a /4" length of heat shrinkable tubing over the
outer jacket of the wire overlapping equally the stripped
and unstripped portions of the wire and heat it until it
shrinks over the cable jacket.
Place a lug on each of the signal leads and solder the
drain wire to the console ground lug nearest the terminal
board.
2)
)
4)
5)
USEFUL TOOLS AND MATERIALS
Wire Strippers:
Diagonal Wire Cutters:
Long Nose Pliers:
Crimping Tool:
Crimp on Lugs:
Heat Shrink Tubing:
Heat Gun:
Xcelite 101 S
Xcelite 54CG
Xcelite 79CG
Ideal 0-428
Vaco 54206
Alpha FIT 1/4" ID
Master Appliance 10008
GROUNDING 2.2.4
A slot is provided at the right end of the back plane for installation
of a 2 inch wide by .0 6 inch thick ground strap to be connected to the
station ground systen. Three 10- 2 by 1/2 inch machine screws are pro 
vided for connection of the ground strap. Use the attached warning
notice as a guide to locate the proper hole positions in the end of strap.
Drill or punch three holes /16 inch in diameter in the strap and mount
the end securely with the hardware provided.
POWER SUPPLY INSTALLATION 2.2.5
The power supply is shipped connected for 125 volt AC lines. If your
line voltage is less than 115 volts or in the 200 to 250 volt range,
reconnect the primary taps for your local line voltage. Refer to Figure
7-6 for the proper connections. If your line voltage is in the range of
200 to 250 volts, change fuse F-l to 1 AMP slow blow fuse.
Locate the power supply under the table top and mount it on a convenient
wall at least one foot from the console. Secure the unit to a wall
with #10 hardware. Route the power supply cable through one of the
large
slots behind the channel 7 attenuator, across to the backplane
power connector, J-4. Note that one edge has ribs for proper polari 
zation. Insert the connector in J-4 and press down to make a secure
connection.
2.2.6
PHASING OF AUDIO CIRCUITS
In stereophonic circuits it is mandatory that proper phasing of the left
and right audio channels be observed. If this is not done, monaural
2-4
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.

212P-1/2
in tallation
source material played back through the system may cancel when received
on a monaural receiver.
All connections in the console are set up in such a manner that the odd
numbered connections of the left and right channels are in phase and the
even numbered connections of the left and right channels are in phase.
In other words, the low side of the left channel should be connected to
an odd numbered terminal and the low side of the right channel should be
connected to an odd numbered terminal. The high sides of both channels
should be connected to even numbered terminals.
Proper phasing may be determined by playing a monaural source through a
channel and placing the channel attenuator in the cue position. If the
source is properly phased, a normal output will be heard from the cue
speaker. An out of phase condition will result in little or no output
from the cue speaker.
HIGH LEVEL INPUT CONNECTIONS
2.2.1
All
inputs to the console on channels 1A-8A and 1B-6B are set up for a
nominal input level of -1 OVU . This means that a level of -lOdBm will
deflect the VU meter to OVU on a sine wave with normal control settings.
All sources should be adjusted to this level for proper operation of the
equipment. In certain types of equipment such as most professional reel
to reel and cartridge tape machines, the level control on the machine is
located ahead of the program amplifier and may cause a noticeable degra 
dation in signal to noise ration if the level control is retarded to
produce the required output. In certain cases it may be desireable to
utilize the VU meter on the machine to indicate proper machine operation
prior to use on the air. In either of these events, it is necessary to
construct an attenuator network and place it in the connecting line
between the source equipment and the mixer input of the console.
2-5
WARNING: DISCONNECT PRIMARY POWER BEFORE SERVICING.