Thomas Capricelli

I got this Amstrad CPC 6128 with a bulky CRT monitor. I’m pretty sure ‘true’ retrocomputing fans would enjoy the ‘genuine’ experience it provides, but I don’t.

The monitor also contains the power supply for the CPC. Both the CRT itself and this PSU are the kind of electronic that don’t deal well with time. I don’t trust them.

Thus, to gain space, confidence and display comfort, I’ve decided to get a VGA adapter.

This is not as simple as it seems. You can more or less twiddle with passive adapters for either VGA or TV (using SCART or composite cables), but it highly depends on the receiver and luck. I’m not a lucky guy.

There are relatively expensive “general purpose” adapters from “retro computers” to DVI and/or HDMI, usually FPGA-based, but lot of software on the Amstrad CPC use some video “tricks” that don’t behave well with those.

Fortunately, there’s a great project, recent (2024), and specifically made and tested for the Amstrad CPC. The developer explicitely tested all those corner cases and fixed his adapter accordingly. To my knowledge, that’s the only adapater reaching this level of compatibility.

It’s called VGA4CPC. It’s based on a Raspberry Pi Pico and requires only a handfull of other components. It’s all open source. I mean “really open source”, as you get not only the source code for the software, but also the KiCad schematics. And not only a blurry PDF of the schematic, or even a photo, as lot of “open source” hardware projects do.

Once found the perfect (for me at least) solution, everything went smooth. I ordered PCB and components (even made a group purchase for this: English, French), soldered it, programmed the Pi Pico (dang, it’s really just a drag&drop), and voilà, it just works.

The Amstrad video signal is 50Hz. The adapter can output a VGA 50Hz signal, which is ideal as it’s synced with the input, but you need a VGA display that accepts that. I don’t have one, so I use the 60Hz output, which will probably give some glitches with demanding games/demos.