Tons of parts I decided to go hit the garage sales again today, hoping for another good retro computer score. While I didn't find any computers or old game consoles, I did find a little drawer unit filled full of electronics components! The asking price was only one dollar, so I quickly snatched it up without even bothering to examine what the parts were. I was very anxious to go through everything and see what I kind of a score I had made!  I had to lay it down on its back in the...

This is part 3 in a series. Check out Part 1: Creating a circuit and Part 2: Using KiCAD . My CNC setup Some time ago I bought a small CNC with the intended purpose of using it to make PCBs. While I have used the CNC for lots of things, I have never tried to make a PCB. The amount of work involved in trying to figure out all the different software programs needed, as well as how they work, has made me constantly put it off. Most of the time I’ve found a way to work around making a...

This is part 2 in a series. Check out  Part 1: Creating a circuit  and  Part 3: Milling the PCB . Prototype on breadboard In order to make my own PCB for the CGA to analog converter project , the first step is to do what is called schematic capture, and get the schematic drawn in the computer. While it’s certainly possible to draw a schematic in a program like Paint, or using something more sophisticated like Illustrator, using a specialized program is a better choice...

This is part 1 in a series. Check out  Part 2: Using KiCAD  and  Part 3: Milling the PCB . When I got my Commodore 128 I was expecting I would just connect the RGBI TTL output to the GBS-8200 knockoff that I have been using with the BBC Micro’s RGB TTL output. Of course the moment I went to do that I realized that I had an extra pin for Intensity with no place to connect it. I found several circuits online that were supposed to convert the 4 bit TTL output to an analog...

Glitchy Not long after getting the BBC Micro working with US power and a VGA monitor, I discovered it had an issue in modes 0 through 3 when hitting return enough times to make the screen scroll. At first the prompt would move over towards the center of the screen, and then it would start filling the screen with garbage. It sort of looked like bad RAM, but I wasn't convinced of that because I noticed that some of the garbage would actually twinkle as I typed, so it appeared more that...