Experiences with a composite video mod for a Sinclair ZX81

[drlegendre .]

"It's interesting that none of my present TVs would tune properly to the RF
of the ZX81 but they will with some of the other RF only computers like the
Coco 1 and Atari 400?  More circuitry in the latter perhaps..."

I'd have no idea about that one, other than I can verify that there was a
lot of variability in the video quality of early game & home computer
systems.

My first machine was a (NTSC) VIC-20 which I ran on a 12" B&W RCA TV set
from the late 1970s. It was not all that bad, really - quite legible with
those massive characters, but not so great for games or anything requiring
color recognition. I was very happy to receive a "proper" S-Video monitor
with my C-64, which arrived some two years later.

On Sat, Jan 2, 2016 at 8:06 PM, Terry Stewart <terry.stewart296a at gmail.com>
wrote:

> On 3/01/2016 2:50 pm, "drlegendre ." <drlegendre at gmail.com> wrote:
> >
> > Thanks Terry, fair enough. =)
> >
> > Has it been done with the ubiquitous 2N2222A? That one is probably in
> > everybody's kit.. it might be even more common than the 3904
> >
> > Wondering.. is there a way to re-purpose that Chan. 3/4 switch as an RF /
> > Composite switch? That way you'd still have a correct (local) RF output,
> as
> > well as the Composite video.
>
> Actually you probably could if you wanted to keep RF.  You'd have to make
> sure it's hardwired to the right RF channel of course but yea..
>
> It's interesting that none of my present TVs would tune properly to the RF
> of the ZX81 but they will with some of the other RF only computers like the
> Coco 1 and Atari 400?  More circuitry in the latter perhaps...
>
> Terry ( Tez )
>