Back to the A1097C monitor again

From: Richard Erlacher <>
Date: Tue Jul 25 20:50:49 2000

If this thing is at all similar th ethe SONY GDM-1950, then even though
that's one of the easiest on the planet to adapt from what it is to what you
want for a PC, it's still a pain in the *SS. What's more it works only in
high-res mode, not in text and unless you acquire one of several VGA cards
unattractively priced at about $150 last time I looked, for the cheapest and
$750 (ovbiously obsolete pricing) for the costliest, you get something that
"sorta" works, though it's utterly breathtaking when it does work.

I've got a similar monitor sitting in the basement, having ignored it once I
went through the usual effort with a friend.

For "trial" purposes, I'd recommend you find the composite-sync pin on the
"application" connector normally located near the top edge of your vga card.
If you solder about a 500-ohm resistor give or take 20%, from the comp-sync
to the green output on your vga card, you can easily see what's going on
with your monitor => display adapter combination in order to determine
whether you can use it as a high-res only monitor. I don't recommend this
for long-term use. It's just to see whether your display adapter will
generate a useable sync pattern. If this scheme works, perhaps with a
little off-center display, then go ahead and make the monitor mod's, and
maybe contact me for a "real" circuit with which to impose sync on green for
use on a typical SVGA adapter. I've used this several times with
astonishingly good results. If your monitor doesn't AC-couple its inputs
you may find the display biased toward the green somewhat. Whether you
adjust this out and live with the resistor approach is up to you.

Another easy thing to do in the event your monitor doesn't like the sync
polarity your adapter likes to put out is to build a little circuit into the
monitor consisting of an XOR gate pack (74HCT136 if you want open drains,
else 74HCT86) through which you run the sync inputs once they've arrived at
your monitor (If you have separate sync inputs on the monitor) and control
the sense of their outputs with a jumper which you set either to +5 or GND,
either of which you can fish up from the monitor somewhere, or steal from
the sync signal. Since the sync line is terminated at the monitor,
probably to ground through 75 ohms, you may need more power than you can
steal to drive the sync signals. If for some reason you can't get +5 at the
monitor, you build a little box and jumper the +5 line on the display
adapter to an unused pin on the DE15. You then build an external box with
your adpater and 5 BNC's on it and go from there.

As you can see, there's ample opportunity for lots of work. When you're
done, however, you still have a fixed-frequency monitor, though a nice one,
and need another monitor and an A/B switch box to switch the signal to the
multisync monitor for text and other uses. Like I said . . . it's a pain in
the gluteus maximus. A pretty decent 20" Sylvania multisync monitor with
really bright and sharp, as well as linear, image costs $279 at Costco.


----- Original Message -----
From: Pete Turnbull <>
To: <>
Sent: Tuesday, July 25, 2000 5:37 PM
Subject: Re: Back to the A1097C monitor again

> On Jul 25, 17:08, Adrian Graham wrote:
> > Hi folks,
> >
> > Assuming I eventually get this monitor working properly with the missing
> > blue signal whilst looking for bumf about it I found this document that
> > basically says I can turn it into a PC-compatible 1280x1024 70-75hz
> monitor
> > for ~$10.
> >
> >
> >
> > Anyone heard of this one? It seems so straightforward I'll do it.....
> I've not seen that particular document before, but IIRC that monitor is
> actually a Sony GDM1960 (or near equivalent), and those were made in
> various OEM versions for HP, Sun, Dec and possibly SGI, differing mainly
> the fitting of the sync sockets. I've seen at least one other account of
> successful addition of two caps, two resistors, two sockets, and links to
> make it work. There's a way to add just one socket for composite sync,
> too.
> > The question that leaps mindwards is if it's a fixed freq monitor what
> > happens to the PC at boot time - do I still see a v.small DOS boot
> Nope :-( And it might not be a good idea to run it at the wrong sync rate
> for too long.
> > or
> > do I get nowt until my GeForce has been fully initialised at 1280x1024?
> Yup :-)
> --
> Pete Peter Turnbull
> Dept. of Computer Science
> University of York
Received on Tue Jul 25 2000 - 20:50:49 BST

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