Re: Well, back into a IIe I am

[Matt Jenkins <mdj@bob.dynalias.net>]

On Thu, 11 Dec 2003 10:08:23 +1100, David Wilson wrote:

> The IIe motherboard used in PAL countries (like Australia, UK etc) was
> released in two main versions:
> 
> "PAL" Rev A/B used in beige IIe. Uses a 50Hz IOU chip and a 14.25MHz main 
> clock
> (instead of the 14.31818MHz main clock on an NTSC board. It has the equivalent
> of the PAL color card (used in EuroPlus Apples) integrated on the motherboard.
> The PAL color circuit has a 4.43MHz color burst crystal and a resistor network
> attached to a shift register to convert bit patterns into the appropriate PAL
> color (but not perfectly - the colors are noticably different from those
> on an NTSC Apple II).

The colours are not just different, they're plain wrong.

> "International NTSC" used in Platinum IIe. Uses same 50Hz IOU and slower 
> main
> clock just like the above but does not have the PAL color card integrated 
> onto
> the motherboard so you cannot just plug the output into the A/V socket on a 
> PAL
> TV. I guess the Aux Slot + Slot 3 video card was designed for this board as
> it would not have been needed on the earlier model.

The card was designed prior to the release of the platinum IIe (The ones
I have here actually have an Apple Australia copyright). If you plug the
video out from a beige IIe into the Apple Composite Colour monitor, the
colours are just plain wrong. Using the output from the card everything
looks normal. Actually, the output from this card is one of the better
video signals I've seen from an Apple II. You get nice crisp white text
on a PAL TV when the machine is in mixed mode. Perhaps this card was
developed by an Apple branch outside of the US.

I believe they changed it 'back' to 50 Hz NTSC on the later IIe's since
that signal produces a correct image on the composite colour monitor
(which was released after the original IIe), just like the output from a
IIc. Unfortunately, that particular monitor is the only one I've ever come
across that correctly decodes 50Hz NTSC signals.

> I actually have a 60Hz IOU chip in one of my PAL IIe systems as
> otherwise the Meg80z 1MB Aux slot RAM card gets the first 7 pixels in
> 80col/Double Res Graphic modes from the wrong bank of memory.

Interesting solution; I decided to just get the whole board, since I
wanted to reclaim slot 3 for my Transwarp. If I ever manage to find a Zip
8000, then I can use slot 3 for a TimeMaster H.O. card.

Cheers,

Matt