[vcf-midatlantic] ZX81/TS1000 with a modern TV

[Dean Notarnicola]

I’ve read that the ULA on some older TS and ZX units do not put out a 100%
proper NTSC signal, something do with the contrast. It may be that modern
TVs have issues, but CRT tuners can deal with it. Considering they are all
demonstrating the same behavior, these units may be fine.


On Mon, May 23, 2022 at 4:32 PM Jeff S via vcf-midatlantic <
vcf-midatlantic at lists.vcfed.org> wrote:

> The K cursor is normal, and standard. The ZX81 does not have any kind of
> intro or status boot screen. If you're seeing the K, then unless there's
> something wrong with the keyboard, you should be able to see any numbers
> you type.
>
> On Mon, May 23, 2022, 4:21 PM Bob Shuster via vcf-midatlantic <
> vcf-midatlantic at lists.vcfed.org> wrote:
>
> > So I have two (2) Sinclair ZX81s (US version - one is still an unbuilt
> > kit), and three (3) Timex-Sinclair 1000s.  I’ve connected them to a TV
> > using an RCA-coax adapter and tuned to the correct channel, but I get a
> > grey screen with the “K” cursor visible.  I’m unable to get past this.
> > This is for all four units.  They seem to tune in white momentarily then
> > switch to fuzzy grey - with the “K” still visible.  This was both on a
> > large 4K OLED set and a small HD LED TV, and I suspect they are just too
> > new to deal with the monochrome signal.  I don’t have a CRT TV to test
> > with, just old monitors (which of course don’t have antenna connections.)
> >
> > Any advice?  I’m selling these, so I’m not getting into modding them,
> just
> > want to confirm they’re working properly.
> >
> > Bob Shuster
>