Radio Systems Millenium-A Analog Console, Installation And Operation Manual

Page: 46 / 88

Radio Systems Millenium-A Console Page 46
Theory of Operation
7.1 Power Supply Circuit Description
The external power supply provided with Millenium Consoles contain internal modules which p15v and -15v at 6
Amps. Each supply is internally fused. Output voltages from the modules are connected to the Power Supply Interface
Board at J1 and J4.
The internal modules are further regulated to p7.5 and -7.5 volts required by the console.
Front panel LED monitoring is provided for all regulated outputs.
The Power Supply Interface Board contains:
1. A common ground point for all power supply and console circuits.
2. Connections from the modules to power header J3 which provides main power to the console, and to header
J2 which provides power for the Cue Amplifier.
3. Status indicator LEDs for all power supply outputs.
4. VR1 and VR2 which provide negative and positive 7.5 volts respectively.
7.1.1 Grounding
The following grounds are tied together at the power supply: A.C. power, power supply chassis, Module A common,
Module B common, console digital ground, console analog ground, console headphone ground, console cue amplifier
ground, and console chassis ground.
7.1.2 Positive and Negative 7.5 volts
VR2 and VR1 are three terminal adjustable voltage regulators which have been set at the factory to p7.5 volts
and -7.5 volts respectively from the output of Module B. These voltages are used to provide power to the front panel
level controls (which in turn control the VCAs) as well as to the CMOS audio switches.
7.2 Six Channel Control Board
7.2.1 Brief Description
The Six Input Control Board provides six identical and independent logic circuits. One circuit is associated with each
mixing channel lid..
Each circuit provides the following:
1. Input select logic and indicators, cue logic and indicators, and on/off logic and indicators.
2. Interface between logic levels and those required by the Six Channel Input Board
3. Interface between the fader and VCAs (located on the Six Channel Input Board)
4. Generation of Mute 1 and Mute 2 control voltages
5. Generation of Timer Reset pulse
6. User remote control and remote interface connections
7.2.2 Detailed Description
As each circuit is identical, only one will be described. There are no connections between circuits. Microcontroller U2
has five ports (RA, RB, RC, RD, and RE). Ports RB and RE are configured as outputs, the others as inputs. The output
port signals are as follows:
RBO High with Input A selected, low with Input B selected
RB1 High to bring the VCA’s to full attenuation
RB2 High when the Program Bus is selected