#monochrome TTL monitors?
6 messages in this thread
Hi:
Does anyone know if an Amiga 500 can be used with a TTL monochrome
monitor like the IBM-PC can use? I've seen an owners manual, and the only
monochrome mentioned is composite video, not TTL. Thanks…
-Mike
IBM standard TTL monochrome monitors cannot be used with the Amiga. The scan
rate is wrong. Peter.
Peter:
After leaving this message, I found a curcuit diagram that allows
exactly what I'm looking for IBM TTL Monochrome–>Amiga via a little curcuit
that adapts the 23pin amiga jack to the 9 pin IBM, and has some other
components in it as well (I don't know what they are, don't even know how to
use a soldering iron). Are you aware of this? if so, do you think it still
won't work, or were you not aware of this modification?
-Mike
Unless the horizontal scan rate of the monitor can be changed it just won't
work. TTL Monochrome monitors operate at about 18 KHz; the Amiga outputs 15.75
KHz. The Amiga can be interfaced to IBM CGA, but not to IBM monochrome.
Peter.
Mike.
Last year I found a circuit diagram here in amigatech for a TTL Mono. circuit,
which I was sucessful in getting to work. I built mine on a card for the A2000
video slot, but the diagram was for an external box connected to the Amiga's
external RGB port. The circuit did work with the three monochrome monitors I
tried, an IBM, an Anadek and a Samsung. If I remember correctly the Horizontal
and Veritcal width trim pots had to be radically adjusted to get an appropriate
sized image, but it did work. I stopped using it because I never found a
monochrome monitor with a high enough phosphor persistance to eliminate the
flicker, which was my reason for trying it in the first place. If you want to
try the circuit and can't find it here, (you may already have the same one I
had) I could reupload it for you.
Scott Horn :'> Mentor Technologies
Scott:
Was the diagram that you found a 2 page document? (with the actuall
diagram on page 2) If so it's the same one that I have. When you say the trim
pots, are those the 2 horizontal & vertical adjustments in the back? Or is this
something that needs a tech to adjust? The main reason I wanted to use it is
because I have a Tandy CM-5 monitor, and 1. I'm basically cheap, and would
rather use what I aready have rather than go and buy another 1. and 2. this
monitor seems to have a very high persistance, so much so as to be a pain is
the A#$ on my MS-DOS machine, but a firend with an Amiga says that it might be
enough to use interlace mode without flicker.
-Mike