Re: IIe Display problem (add'l info)

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

Donald C. Lee <coach41@pacbell.net> wrote:

> The text is displayed is displayed "double" (ie AAppllee IIIIee) during
> bootup and as well as time programs are running.  The Hi-Res graphics
> display is also screwed up.
>
> I ran Appleworks through my IIe and it works fine.  So the problem with
> my display seems isolated to the 40 column display.  Any suggestions by
> anyone on what to look for?

It sounds like there is a fault in the video circuitry which is forcing
the output to be displayed as if 80 column mode was active, even though
it isn't.

Your hi-res graphics problem is likely to be the same - the hardware is
forcing the screen to operate in double hi-res graphics mode, even
though the software thinks it is in single hi-res graphics mode,
resulting in garbage or duplication for seven out of every fourteen
columns (assuming monochrome output).

I'd need to review "Inside the Apple IIe" to narrow the problem down
further.  

It might be as simple as a dry joint or short on the logic board, or it
could require a chip to be replaced.  Without deeper research, the most
likely candidate is the IOU chip, which is one of the 40 pin custom ICs
in the IIe.  If I'm right, then the only way to fix it would be to
replace this chip, and the only convenient source would be a matching
IIe.