Vector (arcade) monitor interfacing issues

From: Tom Jennings <tomj_at_wps.com>
Date: Fri Oct 8 01:12:28 2004

On Thu, 7 Oct 2004, Brad Parker wrote:

> Tom Jennings wrote:
> >
> >If the generator turns off write current (eg. Z axis off) when
> >"at rest" you can let the beam rest whereever you want. If it's
> >a 4-quadrant system eg. location (0, 0) is X=0V, Y=0V, you can
> >simply multiply X and Y by 0 when Z=0, aka turn off X and Y.
>
> I think the problem is not the phosphor, (i.e. turning off Z) but where
> the "drawing machine" leaves the deflection drivers.

It wasn't a concern for the phosphor, but the suggestion that
maybe "Z" could be used to detect when the beam is "parked"
as opposed to being arbitrarily placed at (0, 0).

> If it leaves the x & y in state where the drivers are turned on fully,
> the transistors get hot.

What I meant was, if you find "Z" off (eg. nothing to be
displayed) then you can put the beam in the center of the screen
and save the transistors, within your adapter.

> (those vector machines were the first time I discovered that software
> could be written to trash hardware :-)

In 1982, when I got a super-early IBM PC (working for
Phoenix Software) the first thing I did was to burn out the
fuse in the monitor with the wrong display-type DIPswitch
setting... apparently the wrong horizontal freq makes the
monitor draw a lot of current, by some miracle the Q didn't
protect the fuse.
Received on Fri Oct 08 2004 - 01:12:28 BST