Studio Technologies 76B 2008 - Manual (Page 13)

Model 76B/77B User Guide Issue 1, July 2008
Studio Technologies, Inc. Page 13
for Surround
The Model 77B requires a minimum of
9 volts DC, 100 milliamperes maximum
for correct operation. (The voltage must be
measured directly at the Model 77B’s 9-pin
connector.) So the maximum interconnect-
ing cable length is directly related to the
resistive voltage losses associated with
the two DC-carrying conductors. As the
Model 76B supplies 12 volts and the Model
77B requires 9 volts minimum, this directly
leads to a 3 volt DC maximum drop due
to the interconnecting cable. Using Ohm’s
law it’s quite easy to determine whether
the selected cable will support the desired
interconnection length. Calculate the volt-
age drop by multiplying the total resistance
(in ohms) of the proposed cable by 0.01
(the square of the Model 77B’s maximum
required current). Remember to include
the resistance in both the DC+ and DC–
wires in the fi gure for the total resistance.
AC Mains Power
The Model 76B is internally confi gured
to operate from nominal 100, 120, or
220/240 volts, 50/60 Hz. Units shipped
to North America are factory selected for
120 volt operation. Units bound for Japan
are generally selected for 100 volts while
our friends “down under” and in Europe
receive units set for 220/240 volts. Before
connecting the Model 76B to AC mains
power, check to be certain that it is con-
fi gured to match the local mains voltage.
Look on the back panel (adjacent to the
power entry connector) for an indication
of the factory-confi gured voltage. Note
that an incorrect confi guration could pre-
vent operation or cause damage to the
unit. Should it be necessary to change
the unit’s operating voltage it must be
performed only at the factory, or by a
factory-authorized service technician.
The Model 76B uses an IEC-standard C14
inlet connector to mate with the AC mains
cord. The AC mains cord should have a
C13 socket affi xed with the wire colors
conforming to the internationally recog-
nized CEE color code:
Connection Wire Color
Neutral (N) Light Blue
Line (L) Brown
Protective Earth (E) Green/Yellow
Safety Warning: The Model 76B does
not contain an AC mains disconnect
switch. As such, the AC mains cord
plug serves as the disconnection
device. Safety considerations require
that the plug and associated outlet be
easily accessible to allow rapid discon-
nection of AC mains power should it
prove necessary.
As soon as AC mains power is applied,
the Model 76B Central Controller’s power
LED will light steadily. The two data activity
LEDs, control console and metadata, may
also light. Each of the connected Model
77B Control Consoles will go through a
power-up sequence, lighting each LED in
Signal Pin Direction
Data+ 1 To/From Model 77B
Data– 6 To/From Model 77B
Data Shield 2 To/From Model 77B
DC+ 4 To Model 77B
DC– 9 To Model 77B
DC Power Shield 5 To/From Model 77B
Note: Connector type on Model 76B is 9-pin D-subminiature
female. Connector uses 4-40 threaded inserts for
locking with mating plug.
Figure 6. Connections between Model 76B and
Model 77B