Sierra Video Manzanita 44VSCP - Manual (Page 4)

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Sierra Video Systems • P.O. Box 2462 • Grass Valley, CA 95945 • (530) 478-1000 • Fax (530) 478-1105
MODEL 44 INSTRUCTION MANUAL
Control panel operation.
The local and / or remote control panel has sixteen
momentary switches. The switch labeling is the
numbers 1 through 4 repeated four times. The first
four switches select the input for output one. The
second four switches select the input for output
two and so on. All four outputs can select differ-
ent inputs or the same input can be selected on
multiple outputs with no ill effect.
CIRCUIT DESCRIPTIONS
Model 44VS and 44C.
The electronics for these models are all on a
single plug in module. The module for the Model
44VS is part number 503146 and the part number
for the Model 44C is 503143. The video circuit
repeats three times on the 503143. The same
circuit occurs only once in the 503146. The
503143 schematic diagram sheet 1 delineates this
circuit for both modules. Similarly the control
circuits which are the same on both modules are
delineated on page 2 of the 503143 diagram. The
audio circuits which are unique to the 503146
module are shown on the 503146 diagram.
Video circuits. Each video input is AC coupled to
a wideband buffer (U1). The output of U1 drives
four crosspoint IC (U2), one for each of the four
buses in the Model 44. U2 is a four input by one
output crosspoint. U2 includes a two line to four
line control decoder.
The output of each four by one crosspoint bus is
connected to an identical output amplifier, U3. U3
is a 50MHz wide band video amplifier with a very
low output impedance (about 0.1 ohms). R10 in
conjunction with R19 plus variable resistor VR1 sets
the gain of the entire Model 44 to 2X. R11 raises
the output impedance to 75 ohms required to
interface to external 75 ohm coax cable environment.
The Model 44CPW has internal terminations. This
means that there is only one BNC connector for
each input.
The Model 44 video outputs are intended to drive
75 ohm terminated lines. Unused outputs do not
need to be terminated.
Control panels.
The local control panel, if ordered with the unit,
will be installed at the factory in place of the
blank front cover. If it is installed later, remove
the blank cover, connect one end of the short
ribbon cable to the mating connector on the front
edge of the Model 44 circuit board. Attach the
other end of the ribbon cable to the connector on
the rear of the control panel. Being careful not to
pinch the ribbon cable, slide the local control panel
between the top and bottom cover until it stops
against the two magnets at each end of the frame.
The remote control panel if ordered is a separate
1.75" high rack mount unit plus separate intercon-
nect cable. After mounting the remote panel at the
desired location connect one end on the cable to
the connector labeled “REMOTE CONTROL” at
the rear of the Model 44 frame. Connect the other
end to the connector on the rear of the remote
panel.
Serial control.
The Model 44’s include built in RS-232 serial
control. Connection is made to a female 9 pin “D”
miniature connector on the rear of the Model 44
as follows:
Pin Function
1 Ground
2 Receive input
8 Transmit output