Sync on Green RGB video

william degnan billdegnan at
Sat Nov 18 17:44:07 CST 2017

On Nov 18, 2017 4:09 PM, "Douglas Taylor via cctech" <cctech at>
> I have a couple of vaxes that output 'unique' video, Alpha 3000 300,
Alpha 3000 400, Vax 4000 VLC, and Vax Station 3100 M76.
> The Alpha and VLC each have a 3W3 type of connector and the 3100 has a 15
pin DEC designed connector.
> What does it take to connect these to inexpensive, modern VGA light
weight monitors?
> Doug

I have played around with that problem.  If you have a converter to get
into a VGA port a newer high-end vga display will be able to adjust, but
not a cheap one.  Because I use my vice vga/digital display for mode stuff,
I use a huge SGI color display for all of my 3w3 outputting systems and I
just switch the cable around.  If you could imagine 5 or 6 systems
clustered around the one display.

I am sure someone here has a technical explanation, but in a nutshell the
3W3 world signal isn't the same as a standard vga and cheap vga displays
can't handle the refresh rate.  Someone will prob. refine my answer but
that's why you can't just stick an adapter on there.

Bill Degnan
twitter: billdeg

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