Re: Problem with apple IIe's monitor

[dempson@actrix.gen.nz (David Empson)]

Ross Witherby <witherr@hotmail.com> wrote:

> I just got an apple IIe, and i'm running applsoft basic. But when i
> switch to graphics mode it goes all weird colours, but is perfect in b/w
> mode.

I assume you mean "... but is perfect in text mode" at the end of that
sentence.

It sounds to me that your machine is behaving perfectly normally,
depending on what you mean by "weird colours".

The Apple II forces its composite video output to monochrome when
displaying text-only screens.  It enables colour output when a graphics
mode is selected, unless you use the "colour killer" switch on the
motherboard to disable colour altogether.

If you are looking at a split screen mode, with graphics occupying most
of the screen and four lines of text at the bottom, the text will
usually be a mixture of green, violet and white pixels.  This is simply
because the computer hasn't turned off the colour output, and the video
circuitry is interpreting the text pixels as if they were graphics
pixels, and they obey the normal rules for coloured pixels in hi-res
graphics mode.

The Apple II can only generate white output in hi-res graphics mode if
two adjacent pixels are set.  An individual pixel will be green, violet,
orange or blue, depending on horizontal placement (odd or even column)
and a colour mode flag which causes seven pixels to shift half a
position.  (This flag is never set for text.)

> It also happens in any program where colour is used, and can be
> unreadable at time(i have to switch the monitor to b/w). Has anybody
> experienced this, and knows how to fix it.

The only way to "fix" it is to not use colour at all.


If you had an Apple IIgs, another option would be to use an RGB monitor.
The Apple IIgs turns off the colour signal while generating text in
split-screen modes, so you get coloured lo-res or hi-res graphics with
monochrome text (and a coloured screen border).

I don't know whether the RGB options available for the Apple IIe also
have this feature.