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WARNING: Disconnect and lockout AC primary power prior to servicing
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6.2.4 Diode ORing
Steering diodes are used to allow the paralleling of two supplies and protection from
one supply going low in output voltage. In the dual supply option, the power supplies
should have the output voltages set as close as possible to the same voltage. There are
monitoring LEDs to indicate the presence of input voltages from each supply.
6.3 Wiring Diagram, Control Cabinet
Refer to the drawing package for RF Flow Block diagrams. The drawings detail the RF
flow path for the different configurations and the interconnections to the Input/Output
Panel (I/O Panel).
6.3.1 RF Flow Path
The RF Flow Block Diagrams will help in the understanding of the RF flow path Wiring
Diagrams. The exciter RF outputs, vision and sound, go to the accessory tray directional
coupler in a single exciter system or to 2 of the 4 inputs of the exciter switcher relay
panel, 1A6. The other exciter’s RF outputs are connected to the exciter switcher in a
similar manner. The selected exciter vision and sound outputs connect to the vision and
sound directional coupler in the exciter switcher option.
•
Sheet 2 and 3, AGC Path: this directional coupler output is cabled to the AGC input.
The diagrams on that sheet show the various accessory tray configurations for the
different size transmitters. The I/O panel also has a cable connection to sample the
transmitter AGC output.
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Sheet 4, this shows the DC power supply distribution, the power supplies are in the
bottom of the cabinet. The thermistor connections will only be used when retrofitting
"classic" CD1A systems with multiple AGC units.
•
Sheets 2 and 3, in a similar manner, the first connection is to the Phase and Gain
module(s) and after one, two, or three P&G units the signal connects to an AGC unit for
each PA cabinet. The AGC output cables go to the RF output connectors on the I/O
panel. Each PA AGC sample is connected to the I/O panel.
6.3.2 Main Controller
The main controller has two levels of control, the CPLD and the microprocessor.
The CPLD is basically a programmed digital logic circuit that supports the life-support
mode. If the microprocessor fails, life-support functions are still active as they are
independent from the microprocessor.
6.3.3 Front Panel Switch Unit
Control Panel (Switch Board) – The switch board uses a different microprocessor, not
the micro module used by the main controller on this list. It is responsible for directing
the