Canon A-200 series Service Manual page 47

The color display adapter board also uses the 68B45 as CRTC. On this board, 32K bytes of dy­
namic RAMs are installed. These RAMs supports 40 x 25 characters or 80 x 25 characters
of text screen and 320 x 200 pixels or 640 x 200 pixels of graphics.
Like the monochrome display adapter board, this board also has the 9-pin connector, however
its pin assignment is different.
This connector outputs various video signals such as RED, GREEN and BLUE color signals,
intensity signal, horizontal drive signal and vertical drive signal.
In addition to this 9-pin connector, the color display adapter board has an RCA-type jack which
outputs video composite signal.
The A-200 is equipped with one or two Canon MDD-211 5-1/4" floppy disk drive(s). Please refer
to separate MDD-221/211 WORKSHOP MANUAL (SY8-0031-721) for any further information on
this disk drive.
The keyboard can be connected to the main unit by means of a 5-pin DIN type connector with
a coiled cable. The 8048 one chip microprocessor is mounted on the internal circuit board of
the keyboard. This processor is used as an interface with the keyboard and the CPU. When the
power for the A-200 is turned on, this processor automatically checks its own RAM or stuck keys
by executing the self diagnostic program.
In this part, we have divided the circuit of A-200 into the following four sections:
• Main P.G.B.
• Keyboard unit
• Display adapter boards
• Power supply unit
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