From: Trevor Johnston (tjohnston at domain oceanfree.net)
Date: Mon 16 Aug 1999 - 00:24:18 IST
Ruairi Newman wrote:
> > Better yet, some way of connecting a machine to a PC monitor ? I used to
> > have such a box, though I'd to give it back to it's rightful owner. Are
> > they hard to make ?
>
> What output do you get from the Amigas?
Amigas were originally designed to be principally connected to TVs, so
their default video signal is 15Khz, the same as a TV's. PC monitors
generally require a VGA signal, which has a horizontal scan rate of
about 29Khz, about double that of a TV's. Unless you have an 1200 or a
4000 you will need some special hardware to double the scanrate of the
Amiga's output. If you have one of these AGA machines, though, you only
need a 23-pin to 15-pin video port adaptor and you can use the DblPal
and DblNtsc modes and the VGAonly program to get a non-interlaced
(flicker-free) 640x512 image. And if you change the overscan settings
you can get a decent sized image from the Amiga. But the aging AGA
chipset is very, very slow in these VGA scan rates.
You'll need an adaptor for the typically non-standard Amiga 23-pin video
port - Eyetech specialise in Amiga hardware, they're at
http://www.eyetech.co.uk. They also have a scan doubler which will allow
any Amiga be used with any VGA monitor, if you want to spend an extra
£80. But what with postage and bad exchange rates even the simple
adaptor will cost about £30!
My new 15" Trust handles the still slightly non-standard output with no
problems, but I tried it with an ancient 14" GOldstar and the computer
wouldn't even boot.
Just to avoid this being totally off-topic, I recommend spending some
time setting up UAE (the Amiga emulator). It can emulate an Amiga
graphics card which solves the AGA speed problem; it needs an extremely
fast computer (>233Mhz at least) to be usable, but I imagine a version
of Linux UAE set up to emulate graphics card on a new 600Mhz machine is
very
nice, and free as well.
Trevor Johnston
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