Re: Color on an Apple II+?

[Rubywand <rubywand@swbell.net>]

Chris Clement writes ...
> 
> Right now I have a green monochrome Zenith monitor on my Apple II+.  I have
> an opportunity to buy a color Apple II monitor, but what do I need in my
> Apple to make use of it?
 ....

     If the monitor is a standard composite color type-- i.e. not some kind of RGB
monitor-- you can plug it into your II+ and get color.

     Composite color monitors typically have an 'RCA type' cable-- looks like a hi-fi
cable-- which plugs into the back of the II+ (back right side, viewing the computer
from the front).

     The II+ has a small Video Level pot on the motherboard near the video output.
(It's right next to the Game I/O socket.)  Mainly, you set this adjustment to get the
most stable 'locked-in' display which is at a good brightness level when the
monitor's Brightness is at a middle setting. Once you have a stable display, most of
the display adjustments should be done on the monitor.

     To check colors, you can run a program from the DOS 3.3 System Master disk named
"COLOR DEMOSOFT" and adjust the monitor Tint control so that the 16 lores colors
match color names on the display. Set your monitor to a bright enough level to see
all of the the colors clearly. The best single indicator of a good match seems to be
Purple (Lores Color #3). Another way to set colors is to start a game which has color
displays and adjust the monitor Tint control until it 'looks right'.

     By the way, the Apple II Reference Manual repeatedly lists "red" as one of the
six standard hires colors. Our II+ has never displayed Red as one of the standard
hires colors; and, conversions of captured screens to different formats do not show
red as a standard hires color, either. Instead, you get Orange. Attempting to adjust
a display to get red as a hires color messes up other colors. (The error is corrected
in later Apple II manuals.)



     Some composite color monitors include a small audio amp and speaker. Usually the
audio cable is a mono mini-jack type (like the kind you can plug into a cassette
player). To send II+ sound to the amplifier, you can solder a wire onto the II+
speaker 'Signal' terminal and run it through a non-polarized cap to the center pin of
a plain (non-shorting) mini-jack mounted on the back of the II+ like this ...


     +5V side
        |
        |
        []< Speaker
        |                                                     Jack* center
        |---------------------|(--)|------------------------o Audio Output
        |                   10uF  10uF                        to Amplifier
        |       2 caps connected as bi-polar capacitor
        |
      Transistor                           _________________ ( Audio GND
       side                                |                   Jack* shell
                                        DC Ground

*Plain, non-shorting mono mini-jack which fits your mini-jack plug.


    "Ground" is DC ground = any motherboard trace area which is connected to the
ground side of the power supply. For example, the outside "shell" of the composite
video output is soldered to ground.

     You can get a bi-polar coupling capacitor at Radio Shack or make one by
connecting two 10uF caps neg end to neg end. The value is not critical, a 2uF-5uF
bipolar cap or two 5uF caps connected back to back is fine. Voltage rating should be
10V or better. (As Michael Mahon has noted a single regular polarized 4.7uF cap is
probably okay-- + goes to the speaker, - to the jack.) 

     When connecting to the speaker, it will not ruin anything if you pick the wrong
terminal-- you just won't get any sound output to your amplifier (like a BEEP when
you do a Reset)-- and you'll need to move the connection to the other terminal . If
you pick the right terminal, the BEEP should come through the monitor's speaker loud
and clear with the volume knob set near a middle position. 




Rubywand