The Sorbus computer

A new development! A minimal 65(C)02 system, called Sorbus designed by Sven Oliver Moll (SvOlli).

Instant Assembler for the KIM-1

A program by Alan Cashin.

The following text and other files are by (the ‘I’) Alan Cashin.

I am currently looking through old material that has been in storage for many years. I came across a listing of my ‘instant assembler’ written for the basic KIM-1 with 1kB (plus a bit) memory. It was written in about 1979 to help enter assembler programs, saving the task of converting mnemonics to hex code. The tape with it on is long gone, so I coded it for the acme assembler then ran it in your excellent simulator and it works.

Corsham projects, a tribute to Bob Applegate

Bob Applegate designed and sold for many years boards of interest for KIM, AIM 65, SYM-1 and the SS50/SS-30 users, his one man company was called Corsham TEchnology.

That ended last year when Bob died, and I miss him. A good friend with whom I exchanged many emails about the KIM-1 and KIM Clone.
I have bought many of his fine products. And many others did also, and due to the open nature of his projects, many variants appeared build by others.

His webpages disappeared in July 2024. His family does not respond to attempts to contact about the legacy of Corsham, many of us tried.

Therefore I decided to duplicate here all I have of Bob’s projects, in a way that makes it more accessible than his webshop sale pages, Github, private email exchanges and older downloads.

Here it is: Corsham Bob Applegate projects.

Enjoy, enhance, duplicate, and keep Bob in our memories, I claim nothing, I do not sell any Corsham product, I do not have more information like gerbers, PCB designs.
This is all Bob ever published!

RetroSpy Technologies produces a range of retro (Vintage) hardware products that are of interest for the KIM-1/SYM-1/AIM 65 owner. Also the PAL-1 user may benefit from the products!
Retrospy is inspired by the Corsham Technologies products and since Bob Applegate is no more among us, produces similar/inspired products.

I bought several products from RetroSpy.
KIM-1 RAM/ROM Board
MOS 6530 Replacement for the KIM-1 SBC
PAL-1 Motherboard Expansion Kit
Bus extender

Other interesting KIM-1/AIM 65/SYM- related boards on the Retrospy shop:
AIM 65 I/O board
SYM-1 I/O board
SYM-1 SymDos I/O board
SYM-1/AIM-65 RAM/ROM board
KIM-1 I/O board
2532 to 2764 EPROM adapter
SD Card Storage System (like the Corsham one)

I should have bought he KIM I/O card also, for the 1541 connector, next time!

How to Build a Computer-controlled Robot

Another book scanned and available on the Books page:

How to Build a Computer-controlled Robot (with a KIM-1) by Tod Loofbourrow, written when he was 16!

2531 to 2732 EPROM adapter

By Roy Edmund Antaw

I hope others may find this useful when trying to replace 2532 ROMs.
It sure ain’t pretty, but it works perfectly.
2732 EPROM to 2532 ROM adaptor, using two 24pin sockets with three bend pins on top socket

Promax MI-650 images, EPROM dumps, information, sources

A Spanish firm developed a 6502 trainer, an SBC inspired by the KIM-1. Hexadecimal keyboard, 6 LED displays, I/O to experiment with. Assembled system, boxed, high quality components like mechanical keys. Aimed at education.

On the Promax MI-650 page you find:

  • Introduction to Promax MI-650
  • Manuals
  • Monitor EPROM images and sources
  • Images of MI-650, MI-650B, MI-650C
  • MI-650 video demonstrations


Three versions were made:

  • MI-650. 6502, 6532 for keyboard/LEDs/audio cassette, 6522 for user I/O, 2×2716 EPROM, 2x2K SRAM. PCB fingers edge connectors for expansion.
  • MI-650B. equal to the MI-650, more convenient expansion connectors.
  • MI-650C, a redesign, same dimensions and layout, with more modern components, like 65C02 CPU, larger EPROM and 65C22 for keyboard and LED.

All three share the same monitor program, patched for the MI-650C to use the 6522.

Updates for various sources, motivated by the find of Jose Vicente Marques Vidal of four MI-650s and our attempt to make them operational again (missing EPROMS mostly).

I build a RC6502 SBC

I build a RC6502 SBC and a backplane. A kit is available at Hein Pragt’s webshop.
Nice build, work fine. I now have a real Apple 1 (replica), the A-One and Briel Replica 1 and this Apple 1 clone!
My experiences here!

Commodore Chessmate

I have acquired a Commdore Chessmate! Working well.

Michael Gardi and Stephen Crane are working on Chessmate emulators. Micheal aims for a physical identical one, Stephen uses cheap but powerfull microntrollers.
More on the Chessmate, and the 6530 024 RRIOT (the ROM contains the opening book!) here.

Add the Apple 1 monitor to the KIM ROM!

The Apple 1 and the KIM-1 are some of the earliest 6502 systems made.
Both are desirable, Apple 1’s sell for lots of $$$ and KIM-1s are getting more expensive.

Luckily we can build a KIM-1 clone that is either cheap and compatible, like the PAL-1, or a bit more authentic as the various KIM-1 boards.
Anyway, a clone has the KIM ROMs, and in E(E)PROM, to make it a KIM-1 clone. Altering is not done, you loose that unique spartan user interface!

The Apple 1 has also a monitor program, often called Wozmon to honor the genius of Steve Wozniak.

And you can combine both user interfaces on a not expanded KIM-1 clone!
I also included the Wozmon as a Setting in the KIM-1 Simulator.

Read more here!