Possible fixes for a potential buyer: https://retrorepairsandrefurbs.com/2021/07/05/sinclair-zx81-restoration/#:~:... . On Mon, May 23, 2022 at 9:12 PM Bill Degnan via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
Just to reiterate, get an original analog black and white TV. The Timex Sinclair TS100/ZX81 is not compatible with modern TVs. These computers do not generate a broadcast TV synch signal so even kinda-old TVs will have issues with the Sinclair. There is someone who made an adapter for the ZX 81 in England, but then you have poss. PAL/NTSC issues to deal with.
This was a topic of discussion a few times over the years in these here vintage computer lists....you can search for these online.
Bill
On Mon, May 23, 2022 at 8:39 PM Glenn Roberts via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:
Ah, ok. I stand corrected. Apologies. Tx.
From: Dean Notarnicola <dnotarnicola@gmail.com> Sent: Monday, May 23, 2022 7:06 PM To: vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Cc: Glenn Roberts <glenn.f.roberts@gmail.com> Subject: Re: [vcf-midatlantic] ZX81/TS1000 with a modern TV
I’ve yet to find a TV that can’t do ATSC and NTSC.
On Mon, May 23, 2022 at 6:26 PM Glenn Roberts via vcf-midatlantic <
vcf-midatlantic@lists.vcfed.org <mailto:vcf-midatlantic@lists.vcfed.org>
wrote:
I have no experience with Sinclair but didn’t they have a built-in RF modulator? That would put out an old style UHF or VHF signal that a modern digital TV can’t decode. I believe you’d need an older TV to test these…
Sent from my iPad
On May 23, 2022, at 5:54 PM, Dean Notarnicola via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org <mailto:vcf-midatlantic@lists.vcfed.org> wrote:
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@lists.vcfed.org <mailto: vcf-midatlantic@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@lists.vcfed.org <mailto: vcf-midatlantic@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