The project started as a way for me to learn how an espresso machine works, and also taste some good coffee. Espresso machines that are worthwhile tend to be quite expensive. However, as with many high end kitchen appliances, it's not a very complicated machine. In fact, it's mostly a pile of copper pipes, a heater and a pump. The entire thing is controlled by mechanical switches and every component is 120VAC so there's not a diode in the entire thing.

This is good news because it means that if you can wire a switch, and braze copper pipe, you can probably fix an old espresso machine, and even if its discontinued you can make new parts with standard plumbing fittings and basic electronic components.

I purchased my machine on eBay very cheaply. As in scrap metal cheap. It's an old machine and the owner didn't really know how it worked, and it was leaking from the heat exchanger. Unfortunately they don't sell that heat exchanger anymore. The machine is a Mini Wega from the 1990s (very similar to, but not to be confused with the Wega Mininova). A used one in good condition is about $2,000 last I checked, so it was a worthwhile project to see if I could get it working again. Here's a photo of what it looked like.