ZX in particular? No wonder, I had doubts it was early Wndows but when it comes to the cost of a then-Windows, no way.
It must've been hard to access all parts needed back then. If you did recently, parts are old and expensive if in a good state.
Really?! I thought the russian retard Dota culture is in full swing, as it looks like it has for the past 10 years? Sorry, although I am in my 20's, I am very disconnected to computers and only ever had one, you know something something poverty.
Amiga 32 can be played on a regular Amiga, yes? All the great adventure titles in one place. How do you mod it? It seems on those consoles if you make a mistake, it's as good as gone.
It feels terrible being young, never being a gamer, yet liking all the old classics but never have owned a console. Not everybody's fave, but NHL and Heavyweight Boxing plus Contra speak well enough.
The ZX Spectrum did predate Windows by a good few years. Basically while in the west we bought (to an extent) the latest thing and threw away the older machines, not considering them viable for "serious" use, people in Russia built clones of those same machines, adding improvements and making them do things that were considered impossible. For example; adding way more RAM, hard disks, floppy drives and more sophisticated graphics modes. These became the machines used in schools and smaller offices, whilst the more advanced machines were only available to the government etc.
But if you want to know how these retro machines can be modified, basically the Russian computer geeks are a perfect example. Basically the chips in computers are constructed of transistors. You can think of them as electronically triggered switches. If you combine the transistors in different ways you can get them to do lots of complex things. A chip, or integrated circuit (IC) is just basically transistors connected together in a specific way for a specific reason.
Now, if you were a Russian hacker in the 80s and your friend had bought a smuggled in ZX Spectrum, you might decide you want one, but can't afford to have one smuggled. So some clever people started to figure out what chips were in there and find russian clones of those chips (usually from the military). They would connect it all together the same way and where they couldn't find a clone for a custom chip (like the spectrum ULA) they would figure out how it worked and use several other chips to make a copy. If they didn't have the right chips, they might make an equivalent from transistors.
When you modify these old machines it's pretty similar, you maybe find a broken burnt out part, you search up the number on the part on Google for example and see if you can track it down or if there's a clone replacement available. If there's no replacement, then you search for the parts data sheet (google again) and then when you understand how the chip works you can look for an alternative. In a lot of cases you just need to wire the part in differently, but in some cases, you can't find the right part so you have to modify the circuit board to accept the new part and do the same job by adding different passives such as capacitors, resisters, inductors and maybe crystal oscillators.
You have to get creative some times with it. But as long as you are careful and don't work on a retro (or any other) computer while it's plugged in with a soldering iron and you don't break anything it's actually perfectly safe to modify them. :-)