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BMX SERIES III CONSOLE
a short circuit will drop the gate of Q208 to ground, which turns the FET off and removes the drive
current from the base of output transistor Q209.
The module's OFF lamp may be remotely controlled by applying a low to the selected remote READY
input. This is routed through U200 pin 4 to U205A pin 2, which will result in a low output at pin 9,
keying "on" OFF lamp driver Q206. This provides the facility of using the module's OFF lamp to tally
the ready state of remote controlled equipment.
Pressing the module or the selected input's remote control CUE button causes a high to appear at the
output of U202B, which is connected to U210A. Circuit U210A is connected in a bistable
configuration, with each positive-going transition causing the output of U210 to change state. The
output of this CUE bistable is routed to CUE relay K2, CUE logic bus drive transistor Q224, SOLO
reset circuit U205C, and to the CUE lamp flasher circuit of U202 and U208. The circuitry around U202
and U208 is a free-running multivibrator. The lamp flasher may be defeated by installing a jumper
between E212 and E213 on the printed circuit board. The output of the lamp flasher circuit is connected
to CUE lamp drive transistor Q225, and to remote CUE tally output switch U201.
Pressing the module or the selected input's remote control SOLO button causes a high to appear at the
output of U202C, which is connected to U210B. Circuit U210B is connected in a bistable configuration,
with each positive-going transition causing the output of U210 to change state. The output of this SOLO
bistable is routed to SOLO relay K4, SOLO logic bus drive transistor Q226, CUE reset circuit U205B,
and SOLO lamp drive transistors Q227 and Q228. The low output from transistor Q227 is also routed
to remote SOLO tally output switch U201.
With Sends
Send relay K1 is energized by channel ON/OFF relay drive transistor Q204. When internal option
switch S206 is ON, Send-1 and Send-2 are always active with PRE-fader selection, regardless of the
ON/OFF status of the module.
4.4 STEREO LINE OUTPUT AMPLIFIER
4.4.1 Function
The Stereo Line Output Amplifier contains the mixing and distribution amplifiers for a console line
output. The console mainframe is supplied with three of these modules; one each for the PROGRAM,
AUDITION and UTILITY buses. Each module supplies four distribution outputs, with each output
capable of supplying up to +28 dBm. The main output is an active balanced design. Patch send and
return points are available for the connection of external processing equipment and/or a patch field.
4.4.2 Circuitry
NOTE: The stereo audio path consists of two identical sets of circuitry. For clarity and simplicity, only
the left channel is described below.
PACIFIC RESEARCH & ENGINEERING
REVISION C
72
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