Service manual

6
OVERVIEW
The ‘Digital’ functions of the d8b can be broken down into 3 main systems; Computer,
DSP, and User Interface. The computer is a Pentium system which is contained in the
Remote CPU with the Power Supply . It communicates via standard com ports (RS-232)
to the DSP and UI systems in the console.
The computer runs Mackie’s real time operating system and handles functions normally
associated with a PC such as keyboard, mouse, disk drives, video, etc. The DSP system
controls all Digital Signal Processing functions in the console. The User Interface system
reads and updates the control surface.
Commands from the UI are looped through the computer. For example, if the Mute
button on channel 1 is pressed, the UI system detects it and communicates the event to
the computer. The computer then tells the DSP system to mute CH-1, and tells the UI
system to light CH-1’s mute LED. Note that the LED is not lit by the UI system directly.
Commands can also be issued by clicking on the monitor screen (GUI). Note: the DSP
communicates the meter information directly to the UI, not looped through the
computer.
meters
Remote CPU
Pentium PC
HDD, Floppy, Video
DSP
A/D – D/A converters,
24 on board DSP chips,
FX cards, I/O Cards
U ser I nterface
(control surface)
Switches, V-pots, LEDs,
Flying Faders, Displays