The ASCII Encoder by Don Lancaster was featured in the April 1973 issue of the Radio Electronics magazine. This encoder was designed specifically for the "low cost keyboard" that was designed by Don and featured in the February 1973 issue. The article is titled "build an ASCII keyboard encoder".
This encoder was built in the YouTube video titled Building Don Lancaster's ASCII Keyboard.
The artwork in the article was used to create PCBs of the ASCII encoder.
PCBs for the ASCII encoder are available at www.kalinchuk.com. You can also use the Gerber file to fabricate the PCB yourself.
Refer to the article for the parts list. Most of the parts are easy to find. MC9818 may be the hardest part to find from this list but there are still plenty available on eBay.
Two additional (and optional) parts are the Amphenol 143-022-01 connector (which is used to connect to the "low cost keyboard") and the Amphenol 143-012-01 connector (which is the ASCII out connector). You can use those connectors or you can solder wires directly to the PCBs.
Below, you will find the final, assembled PCB.
TODO
The encoder was connected to the "low cost keyboard" to finalize the ASCII keyboard. I used 390 ohm resistors on the 000-111 lines of the keyboard-encoder connection.
