Sinclair ZX80 / ZX81 / Z88 Forums

My primary goal was to make a version that anyone can make at home.

Then maybe reduce it with a PCB from China.

I would never replace DIP-size with SMD-size, because I have no tools or experience to solder that.

Soldering SMD is not as tricky as it seems at first. Use enough flux, so the solder will automagically find it's way to the pins.

You can solder it even with one of those dirt cheap hobbyking stations.

Just got me a cheap 858 hotair, though. Want to learn soldering with solder paste. I'm practicing desoldering at the moment with it (desoldering parts from 2 broken printers, I got from friends).

oooooo, very interesting indeed, smd soldering is a lot easier than people think except 0402, you can buy cheap smd practice kits for £2-£3 from ebay.
So if my understanding is correct, you have the necessary code, a compatible chip to use and your 'just' need the PCB to connect it all up?
This is definitely something I'm interested in, wish I could offer my help to speed things along.

I''m also very interested. After watching a lot of tutorials for some time of people designing and etching their own pcbs in various ways I bought some single sided pcb's a while back but the use of ferric chloride was a bit concerning so I've never actually had a go at any of it. Having a batch of pcbs professionally manufactured in China leaving the smd work to do myself would be a preferable way to go for me although I have little experience of that too.

You can use lemon juice, salt and hydrogen peroxide in place of ferrochlorid. Se link to video in one of the previous comments.

Thanks Martin, I've seen the heat free toner transfer method recently but I've not seen the lemon juice and peroxide etching before. That would be good to attempt. Have you built a working board from your design?

Tezz wrote: ↑Mon May 08, 2017 2:39 pm Thanks Martin, I've seen the heat free toner transfer method recently but I've not seen the lemon juice and peroxide etching before. That would be good to attempt. Have you built a working board from your design?

My heat free transfer didn't have the right mixing ratio, so the tracks loosened during etching. I'll have to start over. It's not going to happen the next few weeks.

I am not sure if it's really worth making prototype boards yourself in these days. Now most suppliers have special offers with 10 boards 100x100 mm size for just 5 US$ plus shipment.
https://www.seeedstudio.com/fusion_pcb.html

PokeMon wrote: ↑Thu May 11, 2017 5:09 pm I am not sure if it's really worth making prototype boards yourself in these days. Now most suppliers have special offers with 10 boards 100x100 mm size for just 5 US$ plus shipment.
https://www.seeedstudio.com/fusion_pcb.html

What a great resource. I was just hunting for a shop that would do small prototype runs. I looked at their site but didn't see how to specify plated through holes. Do you know if they offer that?

Best,

-mark

Yes - you can use Eagle or similar. If you have 2 layers they are automatically plated through.
There is no special fee for that, it's standard. As well as silk print.