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BMX SERIES III CONSOLE
CUE command is connected to U5A and the SOLO command to U5C. A meter display priority is
required, since it is possible for the Meter Switcher to receive CUE and SOLO commands simulta-
neously from different console modules. This priority is selected by internal option switch S6. CUE
will have priority when this switch is open, and SOLO will have priority when it is closed.
The output of CUE logic circuit U5A is routed to CUE tally drive transistor Q1, CUE select relay K3
drive transistor Q2, and through diode CR3 to the base of meter relay drive transistor Q3. The output
of SOLO logic circuit U5B is routed through U5D to SOLO tally drive transistor Q4, and through diode
CR2 to the base of meter relay drive transistor Q3.
Whenever the CUE or SOLO function is engaged, transistor Q3 will drive meter relay K1 to select the
output of amplifiers U1 and U2. These amplifiers are required to bring the -10 dBu nominal level of
the stereo CUE or SOLO signal up to either the +4 dBu or +8 dBu level required by the AUXILIARY
meters. The gain of left channel amplifier U1A is adjusted by trim potentiometer R5, and the gain of
right channel amplifier U2A is adjusted by R19. These amplifiers, along with their unity gain inverters,
U1B and U2B, provide balanced outputs through the meter relay to the AUXILIARY meters.
4.13 REMOTE LINE SELECTOR
4.13.1 Function
The Remote Line Selector provides a selection of ten stereo input signals switched to one output. Up
to two parallel-input selector modules may be installed in the BMX III. The inputs and outputs for the
modules are all brought out to the connector panel for ease of assignment. Typical applications include
use as a line pre-selector ahead of input modules and tape recorders.
4.13.2 Circuitry
This module consists of one ten-station stereo selector switch fed from ten common remote inputs. The
switch used is equipped with a mechanical lockout mechanism to prevent actuation of two or more
buttons simultaneously.
4.14 VU METER POWER REGULATOR
4.14.1 Function
The VU meter power regulator assembly is mounted on the bottom of the console mainframe below the
Remote Line Selector positions. This location was selected to allow for ease of maintenance. It
provides regulated ±16 volt DC power to the VU meter buffer amplifiers via the distribution board,
which is mounted inside the mainframe immediately below the meters.
4.14.2 Circuitry
The +22 volt console power is regulated down to +16 volts by series regulator U1. The -22 volt console
power is regulated down to -16 volts by series regulator U2. The various small components around the
PACIFIC RESEARCH & ENGINEERING
REVISION C
86
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