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Re: Display for Apple IIGS



MdntTrain wrote:
On May 8, 8:32 am, Steven Hirsch <snhir...@gmail.com> wrote:

limtc wrote:

As I hope to have a proper display for my Apple IIGS so that my son
can program on one of them, my question is what is the proper way to
do this? What compatible monitors are there? Any conversion video
cable (RGB to VGA? RGB to Component?) that can do the job well? etc.

At MndTrain's suggestion, I purchased a Highway Model 100 RGB --> VGA
converter ($200+).  Unfortunately, my experience was not anywhere near as good
as his and it shows a lot of color aliasing and banding on my IIGS.  I sent my
unit down to him for an A-B comparision to eliminate my computer and monitor
from the equation.  The unit may simply be defective.

Until we can figure out why my results are so poor, I would urge caution
before considering this approach.  With the number of classic computer
hobbyists out there staring at Ataris, Apples, Commodore, etc. with dying
monitors, it's just beyond me why no one has been able to come up with a scan
converter that actually works properly for these small systems.  Doesn't seem
like it's rocket science, particularly with talented folks like Mike Mahon
around :-).

There is an Apple 2 --> VGA board under development, but AFAIK this is
intended strictly for use in a IIe.

Steve


It's true it's not rocket science, but it almost is.

Seems like some people are expecting a very simple solution on par
with a Macintosh peripheral, or an Apple-produced IIgs peripheral... a
solution for "the rest of you."    But although it's not rocket
science, it's now what I'd called "hobbyist science" -- more akin to
the early days of Apple I and II hardware hacking, albeit it far
easier in using off-shelf components than having to actually do wire
wrapping.  Still, hobbyist science takes some doing and perseverance.

The IIgs video solutions in Rubywands FAQ really are no longer decent
options.  They were at the time of writing, but now they're too old --
the referenced screens are too old or too small, and products
mentioned are NLA.

Among today's solutions, I've covered a variety of them in great
detail in several posts here in the past:

- IIgs -> SCART LCDTV (simplest, very good results, best for non-USA
although
             USA people can use the Samsung 910MP).
- IIgs -> Highway 100 VGA (the best results circa 2006, present
results TBD).
- IIgs -> Averlogic AL250 VGA experiment -- works great, need someone
to
            design analog anti-aliasing output filter.

As Ferdinand recently pointed out, it is quite simple to low-pass
the "chroma" part of an RGB signal by connecting three small-value
capacitors bridging the R, G, and B signals to each other.

Although more sophisticated filtering could be designed, this provides
a very simple way to experiment with rolling off the high frequency
chroma response without in any way lowering the monochrome frequency
response (for text).

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."