TWO MONITORS CONNECTED AT ONCE by Jos Schilders
Owning an Atari ST mostly means owning two monitors; many
programs require a color monitor, while others only run on a
SM124 Hires monitor. This means that you are almost constantly
changing monitors if you want to look at some new programs. And
when I once changed my monitor while I could see the monitor
outlet from the inside, and saw how fragile it was build, I
decided that I wanted to make a monitor switch.
There are several possibilities to build a monitor switch; inside
or outside the computer. But due to the fact that I travel a lot
to user meetings etc, I decided that it should be an inside
Then I searched for the easiest way to connect a second monitor,
and I found it near the place that is reserved for a future
modulator. If you look at the atari's PC-board you see a large
empty space between the monitor outlet and the diskdrive outlet
(On a 1040STF). On the bottom edge of this space you see a row of
ten holes. 520ST owners may have a few components soldered in
them. Leave them there.
This is the place we want to connect our second monitor. Building
the second monitor outlet is actually quite simple. First you
have to make two holes in the back of your ST, one for the switch
and one for a suitable monitor plug. I suggest you use a 9-pin D-
plug ("Joystick-plug"), for the simple fact that is a cheap,
easy-to-get and reliable plug. Mount the switch and the plug in
the corresponding holes and connect them according to this
| |¯¯¯¯¯¯¯¯¯¯¯¯¯¯| | s=Sync
| | |¯¯¯¯¯¯¯¯| | | r=Red
Os Or Og Ob Oa \ \ \ 3x g=Green
| O---O---O---O | / / / Resistor b=Blue
| | _______| \ \ \ 33 Ohm a=Audio
| | | _______| | |
| GND AUDIO | _______| |
| (SEE | | _______|
| TXT) | | |
| | | |
O O O O O O O O O O
You can of course use another pin-layout on the monitor plug.
Audio comes from pin 1 of the original monitor plug, which is
easy to reach. The back of the monitor plug consist of a number
of angled metal strips. scratch the upper left one a little to
remove oxyd and solder a wire to it. This is your Audio line.
Connect it to the proper pin on the 9-pin plug. The GND Signal
comes from the case of the SHIFTER. (it's a little metal case in
the middle of the PC-Board).
Then cut the upper left strip of the "real" monitor plug (the one
that leads to pin 4) and connect a wire to each half. Connect
these to a normal single-pole switch. This is your monitor
After this, you'll have to make your own cable to your color
monitor. Since all monitors are different, I can't give a
standard solution here. But you don't have to worry about
wrong connections. You can't miss the GND pins (the whole lower
row), and as long as you put SOUND and SYNC correctly, all you
can get is some weird colors. Just switch some wires and your
colors will be alright.
The text of the articles is identical to the originals like they appeared in old ST NEWS issues. Please take into consideration that the author(s) was (were) a lot younger and less responsible back then. So bad jokes, bad English, youthful arrogance, insults, bravura, over-crediting and tastelessness should be taken with at least a grain of salt. Any contact and/or payment information, as well as deadlines/release dates of any kind should be regarded as outdated. Due to the fact that these pages are not actually contained in an Atari executable here, references to scroll texts, featured demo screens and hidden articles may also be irrelevant.