Mac-se-video-converter: Compact Mac to VGA signal converter using rPi Pico

github.com

58 points·zdw··9 comments

This is cool, but what I really want is the opposite. I want a way to replace the motherboard in a classic Mac with a Raspberry Pi supplying an analog video signal to drive the monochrome tube.

Here you go: https://www.instructables.com/Turn-a-Broken-Mac-Classic-Into...

I'd love to have a generic HDMI-> CRT interface, but that's a bigger ask.

Another project driving the old Mac CRT: https://trmm.net/Mac-SE_video/

Kind of excessive for something that can be done with some passives if you don’t need to also scan-convert…

Indeed, I believe 512x342@60.15 is almost certainly within the range of what every LCD these days can sync to.

Compact Macs have a horizontal scanning frequency of 22.2kHz. Good luck finding an LCD that will sync to that.

Fun bit of trivia: Compact Macs also used the video scanning sync timing to feed the audio DAC, producing 8-bit audio at 22.2kHz. Pretty good for 1984!

Compact Macs have a horizontal scanning frequency of 22.2kHz. Good luck finding an LCD that will sync to that

Many will go down to 15kHz (CGA), and some EGA modes also use 22kHz:

http://15khz.wikidot.com/

It's the opposite of excessive. If you need scan conversion, which you almost certainly do, this is far cheaper than just about anything else you can use to get a usable video signal out of a compact Macintosh.

Reply on news.ycombinator.com