24 May
2020
24 May
'20
3:47 a.m.
-----Original Message-----
From: Tony Duell <ard.p850ug1 at gmail.com>
Sent: 24 May 2020 10:28
To: rob at jarratt.me.uk
Cc: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>;
Paul Koning <paulkoning at comcast.net>
Subject: Re: Alternative Monitor for VAXmate
On Sun, May 24, 2020 at 9:23 AM Rob Jarratt <robert.jarratt at ntlworld.com>
wrote:
Everything I have ever heard would suggest that making my own flyback is the hardest
option and well nigh impossible without expensive industrial equipment. If there was a way
I would certainly look into it. I have no idea where to begin, but if anyone on this list
has any pointers?
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.
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!) 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.
-tony