Alternative Monitor for VAXmate

Dave Wade dave.g4ugm at
Sun May 24 04:56:36 CDT 2020

> -----Original Message-----
> From: cctalk <cctalk-bounces at> On Behalf Of Tony Duell via
> cctalk
> Sent: 24 May 2020 10:28
> To: rob at
> Cc: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at>
> Subject: Re: Alternative Monitor for VAXmate
> On Sun, May 24, 2020 at 9:23 AM Rob Jarratt <robert.jarratt at>
> wrote:
> >
> > Tony, are you aware of any device I could buy or circuit I could build to get a
> decent image out of it? It doesn't have to be perfect, but at least usable.
> Unfortunately not. That 26kHz horizontal frequency is the problem...
> It's not close to any of the PC standards (MDA, CGA, EGA, VGA). Nor
> television (I even thought of the French System E 819 line, but that's around
> 20kHz). And those are the common standards.

The only think I found was a reference to the IBM 3179G.  

> I think you options are either to try to modify VGA monitor to scan a little
> slower, to design some kind of standards converter (which is a lot of work!)

If the output is digital, would it be possible to build an FPGA scan converter to go to VGA?
Is the output always 26Khz?

> or to make a new flyback transformer. The last would be what I would look
> into, if only because it keeps the machine original
> You would probably have to vacuum-impregnate the windings to prevent
> flashover, but the model internal combustion engine crowd make their own
> ignition coils and manage to do things like that.

Sounds harder to me than an FPGA scan converter...

> -tony


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