| Attachment | Size |
|---|---|
 Schematics | 482.91 KB |
| BOM | 112.39 KB |
 Short movie | 25.82 MB |
| Popular Electronics April 1974 article | 673.28 KB |
Last year I developed an ASCII Keyboard Tester (see https://www.applefritter.com/content/ascii-keyboard-tester and https://www.applefritter.com/content/ascii-keyboard-tester-pcb-and-kits) to please my curiosity in the electronic workings of the Apple-1. Great to see this scene of enthusiasts is so alive.
I came across an article by Don Lancaster in the Popular Electronics April 1974 issue about the ASCII Keyboard and Encoder. They use a Monsanto MAN-2 display, a 5x7 dot matrix. Using a 2513 character generator, it displays a single character that is typed in on the ASCII Keyboard. It is on page 29/30, some PDFs around there are missing these specific pages, so I attached the article here for reference.
Anyway long story short, I designed a Character Generator Tester, which shows the characters that are generated by the 2513. I use a KingBright TA-07-11EWA as a display. It also supports 2316B, 2716 EPROM and 2816 EEPROMs. So it enables you to test Character Generator’s for the Apple-1 and Apple ][, and you can test self made EEPROMS (or 2513 drop-in’s) that should replace the originals.
It uses a clock with stepping function and speed adjust. So you can see the row address counting and how the display is being built up. It also has LEDs that show the 6-bit ASCII input to the character generator. It uses the same power supply connector and DIP-16 keyboard connectors as the ASCII Keyboard Tester, the -5V is generated on-board. I also added an 8-bit counter output to feed for example the ASCII Keyboard Tester or other experiments, I needed the binary counter anyway for the display.
I tested it with Signetics 2513N from date 7703, a RO-3-2513 out of a ITT 2020 (early 79) and a 341-0036 (2316B) out of an Apple Europlus. Works great, but I was unable to test the (E)EPROMS yet, I assume they will work as they have the same pinout as the 2316B?
The design was a lot of fun, coming from a software background, I am learning a lot of electronics. Schematics and BOM is attached, let me know what you think about it. Kits are coming up as well.
Regards from Holland,
Bobby
That's pretty nifty!
I like it. Congratulations on the work.
That's great, although also maybe a little overkill I really want one!!
I didn't check, but thought easier to ask... are the board files attached or available project through one of the big suppliers?
If a KiCAD project or at least the Gerbers file is posted then anyone can easily order boards from JLCPCB or PCBWay or a few other places.
That'd be super sweet. I'd probably not be able to resist building some.
A sort of related project, this one is software, which I have used to view .bin files before burning them to EPROMs is here in my GitHub:
https://github.com/softwarejanitor/chargen2png
It should work on Linux as long as you have Perl and Perl-Gtk installed. It probably will work on MacOS too if you install those using Brew and CPAN. Windows I have no idea since I don't have or use Windows, but I imagine it might work with Strrawberry Perl or something. I don't know and have no way to test it.
I like to keep this hobby affordable for me, so for now I offer PCBs and Kits in the sale and trade section, see: https://www.applefritter.com/content/character-generator-tester-pcb-and-kits
Any questions please let me know, also open for 'reseller' interests.
That is a terrific value-add KBD tester. Very nice work indeed!