Great Hierophant
Veteran Member
The Amstrad PC-20 seems to be one of, if not the rarest, of the Amstrad IBM PC compatible machines. The wedge-form factor computer was released as the Sinclair PC-200 in the U.K. but as the Amstrad PC-20 in the US and apparently other parts of the world. I have seen photographs with the machine with both ISO (vertical Enter key) and ANSI (horizontal Enter key) layouts. The Sinclair model had an RF output for CGA graphics, most unusual for the time for a PC compatible device. RMC The Cave did a video which featured the Sinclair model and showed a sample of its CGA output : https://youtu.be/SAOlkM8HN9g (at 10:20 and 13:04).
CGA is generally thought of as an NTSC-friendly standard because it uses 60Hz, does some simplistic digital RGBI to analog NTSC direct composite color conversion and supports artifact color in 320-pixel and 640-pixel resolution graphics modes. If the refresh rate is reduced to 50Hz, its digital RGBI color can be translated into analog PAL-friendly direct composite color, although artifact color is lost due to the decoding of a PAL signal.
I have also read that some PC-20s may have come without an RF modulator installed. My question is whether the American version has an RF output and what does its CGA look like. Does it look like IBM's or something very different? (Recall that the PCjr. had an RF modulator).
The only really good picture of an "American layout" PC-20 I have found online is here : https://ajovomultja.hu/exhibition/amstrad-pc-20. Here is another pair of pictures of the American Layout version, it shows a space for an RF modulator : http://kath-rottal.homeunix.org/computermuseum/computer/Schneider : Amstrad/Amstrad PC 20/index.html
CGA is generally thought of as an NTSC-friendly standard because it uses 60Hz, does some simplistic digital RGBI to analog NTSC direct composite color conversion and supports artifact color in 320-pixel and 640-pixel resolution graphics modes. If the refresh rate is reduced to 50Hz, its digital RGBI color can be translated into analog PAL-friendly direct composite color, although artifact color is lost due to the decoding of a PAL signal.
I have also read that some PC-20s may have come without an RF modulator installed. My question is whether the American version has an RF output and what does its CGA look like. Does it look like IBM's or something very different? (Recall that the PCjr. had an RF modulator).
The only really good picture of an "American layout" PC-20 I have found online is here : https://ajovomultja.hu/exhibition/amstrad-pc-20. Here is another pair of pictures of the American Layout version, it shows a space for an RF modulator : http://kath-rottal.homeunix.org/computermuseum/computer/Schneider : Amstrad/Amstrad PC 20/index.html
