Sinclair ZX80 / ZX81 / Z88 Forums

Hi,

I have recreated a replica of ZX80 using Grante Searle's foil patterns, which I repaired (therer were 2 small errors) and I created the drill data and white silkscreen, so the PCBs are drilled, both sides tin-plated and connected with vias. Almost like an original ZX80. I created small batch of PCBs for Czech community and there are still few left. So if someone wants the PCB and/or programmed 2532, just write me.



I used keyboard overlay which sells RWAP http://www.sellmyretro.com/offer/detail ... brane-1479. It works perfect.

You cand find more information at http://translate.google.co.uk/translate ... =&ie=UTF-8. Sorry, the pages are only in Czech for now. Google translate is poor, but for a lot of people better than Czech )) You can use language translation icons on the upper right side of my website.

Regards

Martin

Hi Martin!

I want one - you have PM

Greetings
Jens (German ZX-TEAM)

Are these complete and ready to plug in and go?

It might be worth listing them for sale on sellmyretro.com

@Martin - PM sent

@Rich - they won't last that long

Hi all,

thank you. I sent reply to all who sent me PMs. If you do not receive it, you can contact me at .

The PCBs are unpopulated and I sell them for production cost. I do not make it for profit. I built my first replica on this design and repaired the erros, so it should be easy to use original ZX80 kit manual to build you own ZX80. There can be problem with obtaining some parts, which I solved. I have some spare EPROMs 2532, which I can program to ZX80 ROM for interested persons. The RF modulator UM1233 can be obtained at http://markhindes.easywebstore.co.uk. Other components should be easily available. If somene wants I have some spare Zilog Z80A or NEC D780C-2 that were in original ZX80s. Unfortunately all uPD2114 are already gone, but they are on eBay and here in Czech a lot of people uses TESLA equivalent MHB2114, which has worse timing but works.

If there will be any spare PCBs I will possibly list them on Sell My Retro and/or eBay, but it really looks like they won't last too long. I made only 20 PCs and 10 were for Czech community, and only 5 are not yet reserved today.

Regards

Martin

I built the replica on the new PCBs and found small problem that I did not notice during the prototpe phase. It required just small almost invisible cut so I repaired all PCBs I will ship tomorrow (more info on my site http://www.8bity.cz/?p=380). The replica works as expected.



Will you find 10 differences?

Regards

Martin

P.S. All boards and EPROMs are already gone. As there is quite a lot of people asking, if you wish yours, try to contact me. If there will be enough interest I could make another batch.

Hi.
Just to let you know that version 1.3 of the "Issue 2" foils will be released soon.
This fixes a couple of graphic tidy-ups, and the re-size (slightly!) to match the 155.5mm x 204mm of my real ZX80 board.

I will release the latest version on my page shortly.

For the foils, please refer to my page as this is the source of my latest version. Other URL in this forum is a copy (authorised by me) from another user and may get out of date.
My official page is:
http://searle.hostei.com/grant/zx80/zx80.html
[Edit by Grant on 7th July 2012 - UPDATED URL !]

Attached is a sneek preview of the latest version. Thanks.

Grant.

Hi Grant - that's good work

Does the change in size mean that the replacement keyboard overlays I sell will now fit this design correctly? It would be nice if you could maybe add a link to them on your page

http://www.rwapsoftware.co.uk/zx802.html

By the way, I am glad that you corrected the ZX81 overlay (as some on the web show the wrong chequerboard patterns).
However, there were a couple of things I did find out when discussing the ZX80 overlay:

a) The chequerboard pattern is actually yellow circles, not squares and the edges are semi-circles!
b) On a real ZX80 you need to look very closely at the chequerboard on T and G. Interestingly the T key starts with a row of semi-circles at the top, whereas the G key ends with full circles on the bottom line, so that resulted in an overlap if you overlaid the two images!

We decided to go for the non-overlapping approach, with the bottom line of G being made up of semi-circles to deal with (b) as that makes more sense

Hi.

Just to let you know that I have now uploaded version 1.3 of the PCB foils to my website.
http://searle.hostei.com/grant/zx80/zx80.html
[Edit by Grant on 7th July 2012 - UPDATED URL !]

Regarding your replacement overlays, the replacement keyboards should fit on the old or the new PCB layout as the overall size change is only 1mm side-to-site (so therefore max 0.5mm difference each side from the centre point), so there would not be any noticeable difference.

On my original ZX80, the overlay doesn't exacly line up with the keyboard overlay anyway (the key legends should shift to the right a fraction), but is not noticeable in use. The purpose of my page is to produce an accurate representation, so this offset is exactly the same as the original machine.

I was in a dilemma when I did the ZX80 overlays, due to the checkerboard issue that you pointed out.
I am assuming that the circles is due to a limitation with the original silkscreen printing process (magnified, the other yellow print is not particularly good either) so I decided to create it as I believe it was originally intended. The top row of dots on the original keyboard checkerboard are particularly poorly defined.
...I may change my mind in future, though


For those who have already built a PCB using issue 1.1, don't worry - changes are minor cosmetic only, mostly under the chips. The size change is not noticeable unless you use a ruler, as it is only 1mm in width (145.5mm --> 155.5mm) and a small change to the length. The picture of the original and my version of the PCB that Martin has built above shows that you would need to look very closely to spot anything different.

(Sorry Martin, the drill details and silkscreen overlay that you did will now be out a bit if you use 1.3 - don't know if you can stretch to match the new layout. Also, the bottom holes are different.)

I have included a changelog on my webpage.
Briefly...
1.0 First public release
1.1 Bugfix (working) release ( ), with improved track accuracy under the chips. The error fix from 1.0 is shown as a link on my site to allow 1.0 etch versions to be fixed easily.
1.2 Pad changes and other minor changes to ensure etched PCBs didn't have shorts between pads and tracks.
1.3 Major review of tracks and tidy up of some of the curves (getting curves to match with beziers, splines etc. is rather tedious!). The other change is a slight resize, as mentioned above.

I don't expect anything major to change now, and I am now happy with the accuracy and look of the tracks. Probably add the silkscreen as another page to the PDF when I get some free time.

I'll add a link to your page shortly, I need to do some page updates.

Regards.



Grant.

Thanks for all your hard work Grant!