Junior Elektor hardware

The Junior Computer hardware and software is described in detail in the books and articles, see there for details.

Note that the Junior has the Elektor bus and coul sue a lot of the cards developed for the EC65/Octobus, but memory layout differences may require adaptations.

Base Junior computer, quite a small system!

Circuit diagram

PCB front

PCB back

PCB layout front (from March 1980 Elektuur article)
Note that this layout is not as shipped, the Junior PCB’s were front/back swapped. The book is correct.

PCB layout front (from Junior Book 1, as shipped)

PCB layout back (from March 1980 Elektuur article)

PCB layout back (from Junior Book 1, as shipped)

LED display PCB and layout

Address sticker

Photo of (stripped clean) PCB front

Photo of (stripped clean) PCB back

Interface card, adds more memory, cassette interface, TTY interface

Circuit diagram part 1, ROM, RAM, VIA

Circuit diagram part 2, TTY interface, audio cassette interface

Interface card  PCB front (note not on scale!)

Interface card PCB back (note not on scale!)

Interface card layout

Backplane PCB, part of it could be used to connect Junior PCB to Interface card.


Backplane layout

Memory layout

Elektor bus

Musicprint kit and cassette interface

The Junior was sold as a kit by the firm Musicprint, read here the extra instructions in the kit.

It took Elektuur some time to add a cassette interface tot the Junior design, a year until the Interface PCB appeared. Many users therefore bought the socalled musicprint cassette interface. See here the description and circuit design.

A 2732 EPROM can be used instead of the 2708 EPROM when you perform the following:
– cut the traces +12 and -5V
– K6 to the VIA,
– K7 to the EPROM.but leave K7 to the 7401 intact for the STEP function.
– /CS from VIA to K3 to move the VIA to page 0E (jumps in the EPROM are adapted for that)
– /OE from the 2732 to ground
– A10 and A11 of the 2732 to the addressbus
– /CS from the 2732 via an inverter to A12 , note that there are two unused ports in the 7402 with grounded inputs,: cut those! and add a pull up resistor

Junior Nederlands

Nederlandstalige artikelen uit Elektuur 1980 en later.

First article Junior Computer March 1980 in color
PDF file of the first two (dutch) articles 3-26 and 4-72 with the complete hardware design
All other Elektuur Junior articles 1980
March 1980 Junior-computer The introduction article
4-72 Junior-computer hexadecimal monitor dump
5-66 KIM Gebruikers Club promotion! nogmaals: junior-computer nog wat aanvullende gegevens
6-56 elektuur uP systemen
8-26 RS 232 interface
9-48 RAM/EPROM kaart 8K RAM + 4,8,16K EPROM
10-42 meer junior-geheugen, memory decode for RAM/EPROM card
11-71 Junior groeit!
All other Elektuur Junior articles 1981
2-54 junior-tekst, show text on led displays
3-54 junior-journaal, practical tips
4-41 Junior-hardware kompleet (PDF file)
4-52 junior-software aangevuld
5-56 junior-uitbreidingen bouwrijp (PDF file)
6-53 Junior Computer als Voltmeter (G.Sullivan)
10-53 EPROM-Programmer
12-46 pseudo-ROM
1-58 EPROMmer (P.R. Boldt)
All Elektuur Junior articles 1982
3-47 Junior spreekt Basic, adapt KIM KB-9 Basic to Junior
4-46 mini-EPROM-kaart
4-50 dynamische RAM-kaart
5-39 Software-uitpluizer (disassembler)
5-62 PSS Prive Software Service (EPROMmer)
5-67 Mini-teller met microprocesssor
7-59 Junior-vektoren ophalen (R. Mattysek)
7-46 single-cycle voor junior-computer (E.Kytzia)
9-74 konnektie tussen basis- en interface print
10-59 Van 6502 naar 6809
11-58 Floppy-disk interface voor junior en andere 6502-computers deel 1
12-26 floppy-disk interface deel 2 (Ohio Scientific DOS)
1-66 verkeerslichtensturing (D. Herzberg)
All Elektuur Junior articles 1983
3-28 Universele geheugenkaart
5-60 morse-dekoder
5-37 junior-programmatester
5-38 ASCII keyboard
5-48 parallel-serie-omzetter voor ASCII keyboard
6-48 RTTY-dekoder
7-73 busy-indicator voor junior
7-73 Centronics interface 6522
7-79 vektor-aansturing voor junior
9-58 VDU kaart
9-66 de muzikale junior
9-74 64K op de dynamische RAM-kaart
10-57 basicode-2 voor de junior
10-72 EPROMmer zonder interfacekaart
11-68 universele terminal
Omnibus busprint
12-44 indirekte files op de junior
12-70 Bus uitbreiding de Elektuur bus
All Elektuur Junior articles 1984
1-68 adresdekodering
2-75 Basicode-2 voor Junior met VDU-kaart
2-66 6502-tracer
3-40 Tapemonitor uitbreiding
4-53 ID-list
4-71 motorschakeling voor floppy drives
6-36 merge voor BASIC files
7-50 RES IRQ NMI indikator
7-68 2716 voor 2708
8-12 start-omleiding voor 6502
8-15 beeldruiskiller
9-72 DOS-uitbreidingen
11-33 de 6845 geprogrammeerd
swap routine voor 6502
6502 tracer
1978 – 1983 Elekterminal All articles in one
PDF file of issues 181 to 231

Junior in English

Junior Computer
elektor microprocessors
RS-232 interface
8k RAM 16K EPROM card
dynamic RAM card
64K on the 16K dynamic RAM card
junior’s growing up!
text display on the Junior Computer
junior cookbook
the fully fledged Junior Computer
sophisticated software for the Junior Computer
the junior reaches maturity
using the Junior Computer as a voltmeter
mini EPROM card
BASIC on the Junior Computer
the Junior Computer as a frequency counter
calling Junior vectors
junior paperware
the Elektor connection
floppy disk interface for the Junior part 1
floppy disk interface for the Junior part 2
traffic light control system
junior program tester
Morse converter
RTTY decoder
busy indicator for the Junior Computer
vector control for the Junior Computer
VDU card
Junior Synthesizer
basicode-2 interface for the Junior Computer
2716/2732 programmer
EPROMmer using the Junior Computer
CPU card
6502 tracer
Get & Go
ID list
merging BASIC programs
screen noise killer
morse training with the Junior Computer
RTTY interface

Junior en francais

Articles published in the french edition of Elektor 1980-1983.

Junior Computer, un ordinateur adulte
le moniteur du Junior Computer
un autocollant pour le Junior Computer
la carte mémoire du Junior Computer
le junior grandit!
lire le junior
chronique du Junior Computer
carte d’interface pour le Junior Computer
de la quincallerie a la programmerie
la carte d’extension en chantier
le Junior en voltmetre
orque junior
le junior parle basic
mini carte EPROM
mono-cycle pour le J.C.
saisir les vecteurs du J.C.
Junior paperware
extension pour l’Orque Junior
interface pour unités a disquettes
interface pour unités a disques souples
commande feux tricolores
déverminag pour J.C.
convertiseur pour le morse
decodeur RTTY



Elektor books

Books on Junior, Paperware on Junior and Computing Specials

(French covers thanks to Gerard Mizzi, English covers thanks to Ruud Baltissen, Spanish cover and scan thanks Joseba Elpalza, thanks to Frank Streichhahn for the German books, thanks to Joan from Barcelona for UK Junior book 3 )

Partial OCR’ed versions of the books can be found here, thanks to Keith Howell. All four Dutch and 1,2, 4 and part of 3 of the English books.

Junior computer 1
Elektuur Junior boek 1 (Dutch)
Elektor Junior book 1 (English)
Elektor Junior book 1 (Spanish)
Elektor Junior book 1 (German)
Elektor Junior book 1 (Italian)

Junior computer 2
Elektuur Junior boek 2 (Dutch)
Elektor Junior book 2 (English)
Elektor Junior book 2 (Italian)
Elektor Junior book 2 (German)

Junior computer 3
Elektuur Junior boek 3 (Dutch)
Elektor Junior book 3 (German)
Elektor Junior book 3 (English)

Junior computer 4
Elektuur Junior boek 4 (Dutch)
Elektor Junior book 4 (English)
Elektor Junior book 4 (German)
Junior computer VIA 6522
Junior computer Paperware
Paperware 1 Dutch- source listings Junior
Paperware 2 Dutch
Paperware 3 Dutch
Paperware 3 German
Paperware 4 Dutch
(thanks Ruud Baltissen and Martin Seine)
Erratum Paperware 4

Elektuur Computing 1
Dutch, Octopus/Samson 6502 computer
Sonderheft German
Elektuur Computing 2
Dutch, More 6502 computer
Elektuur Computing 3
Dutch, More 6502 computer
Elektuur Computing 4
Dutch, EC65K and more

Elektuur Computing 5
Dutch, Z80 and more 6502 hardware and software
Elektor Computing 5 German

RB Specials

When I was an editor at Radio Bulletin we published several specials. Some were additions to the magazine, two specials were on sale.

RB CB Special 1980. The early KIM-1 articles by Dick de Boer.
RB CB special inhoud
De Keuze van een Personal Computer, Hans Otten
rbspecialmicrocomputers, D.M. de Boer
EPROM programmeerapparaat met de KIM, J.M. v.d. Peijl
Grafisch TV-display, D.M. de Boer
Mastermind op de KIM, J.M. v.d. Peijl
Morse-decodering met de KIM, M.B. Immerzaal
Programmeren, stap voor stap
Zero page shifter. D.M. de Boer
Automatische registeruitlezing, D.M. de Boer
CB Special 1982. KIM uitbreidingen Paul de Beer en Hans Otten.
Inhoud CB Special
EPROM programmeerapparaat PET en KIM, J.M. v.d. Peijl, P.G.J. de Beer
Geheugenuitbreiding voor 6502-systemen, H.J.C. Otten, P.G.J. de Beer
Mini-assembler voorde 6502, M. Dohmen, R. Koekoek
ASCII-toetsenbord UART-schakeling Baudrate generator, H.J.C. Otten
5V 20A Voeding voor microprocessorsystemen, Manudax
AMI-COS getest, overdruk Radio Bulletin Sepember 1980, H.J.C. Otten
De microprocessor van morgen, P.G.J. de Beer, H.J.C. Otten
uprofessioneel bijlage 1980, BEM Brutech

PC utilities for 6502 KIM-1

Updated December 2020, Linux compilation checked, bugs fixed, online program for comverting binary to wave file.

To aid in the handling of KIM-1 program and dataformats I have written some programs for Windows and Linux (Raspbian), sources included.

KIM Tape WAV to BIN conversion
Convert 8 bit hex formats
KIMPoser Tape Convert hex to WAV online
KIM Tape Convert BIN and BIN to WAV
KIM-1 simulator
Pascal-M cross compiler

All programs come with source (Free Pascal Lazarus), compiled for Windows but thanks to Freepascal and Lazarus also compiled and tested on Linux (Ubuntu and Raspberry PI OS).

Convert 8 bit hex formats

A general purpose utility to convert common 8 bit hex and binary formats, such as Intel HEX, Motorola S records, MOS Papertape, hex format, and binary files.

source files (Freepascal Lazarus).
Convert8bithexformat Setup for Windows, Executables for Ubuntu and Raspberry PI OS
Available formats:
– BIN binary, raw data, no formatting, no information on start address.
– HEX formatted as hex numbers raw data, no start address included.
– IHEX Intel hex 8 bit format, multiple memory block, start address included.
– PAP MOS Technology papertape format, multiple memory blocks, start address included.
– SREC Motorola 8 bit S record, contiguous memory block, start address included.
– A1hex Apple Woz monitor hex format, start address included.
– KIM Tape as used in the KIM-1 Simulator as emulation of audio tape files.

KIM-1 simulator

6502/65C02 CPU emulation, disassembler, TTY, KIM-1 keypad and LEDs.

See the KIM-1 Simulator page for more information.

KIM Paper

Note that the Conver8bitHexFormat program is also capable of converting to and from Papertape format from many more formats.
Originally written for the launch of the MicroKIM, an older version is on the support CD.

When you attach a serial device like the teletype or a modern PC with Hyperterminal you can use the TIM monitor of the KIM-1. One of the functions is loading from and saving to a papertape device on the teletype. Now since this is a way to load and save data as a textfile this is in fact quite useful.
The Micro-KIM triggered me to modernize my conversion utility for MOS Technology papertape format dating from 1983, VAX/VMS and Turbo Pascal. A Windows and a commandline/console version are available.

KIMPAPER for Windows

A program for Windows to convert between papertape and binary format.

Windows setup KIMPAPER
Sources (Freepascal Lazarus, build also on Linux)


Not too modern, but handy, a commandline utility. Does exactly the same as the Windows program KIMPAPER. Runs fine in a commandline DOS box. Can also be compiled for Linux with Freepascal. In the KIMPAPER DOS archive the program, source and information on the program and papertape format can be found.

KIM-1 MOS Technology BIN papertape format conversion utility, Hans Otten, 2007 v1.1

Syntax is:
KIMPAPER [-[b|p] filename [startaddress]
C:\MICROKIM\kimpaper -h
KIM-1 Mos Technology BIN papertape format conversion utility, Hans Otten, 2007 v1.1
Syntax is: KIMPAPER [-[b|p|h] filename [startaddress] first parameter switches
-h help
-p convert to papertape
-b convert to binary
second parameter (first if no parameters, assumed binary to papertape)
name of file to convert
.BIN for binary, forces conversion to PAPertape
.PAP for papertape, forces conversion to BINary
third parameter (assumed 0000 if not present)
startaddress for BIN to papertape conversion
Files of type .BIN wil force conversion to papertape.PAP
Files of type .PAP wil force conversion to binary .BIN

C:\MICROKIM\kimpaper mastermind.bin 0200
KIM-1 Mos Technology BIN papertape format conversion utility, Hans Otten, 2007 v1.1
C:\MICROKIM>kimpaper mastermind.pap
KIM-1 Mos Technology BIN papertape format conversion utility, Hans Otten, 2007 v1.1
Start address 0200 in file mastermind.BIN

Convert KIM tape to text

KIM Tape to Text is a utility to convert between binary format of a KIM-1 tape dump to a DOS text file.
The KIM tape dump is a binary file and is just a dump of part of the memory of the KIM-1.
This binary file can be a text file as used in editors Micro Ade or CW Assm/TED.
By using the tape write routine in the KIM-1 one can write an audio file on cassette.
When this audio file is captured on a PC as WAV file (22K, mono) this can be converted back to a binary memory dump with ED’s Utility KIMTape
These text files can be converted to DOS text files with this utility.

First open the binary file. If this is recognized as Micro Ade or CW Moser format, the Save as text file can be used.

Windows program.
Full source for Freepascal and Lazarus, no Windows dependencies. Compiled on 64 bits Windows 10 as 32 bit application.

Note on detection of assembler editor type
1. Micro Ade file must start with CR: when present this is Micro Ade
line nr follows 2 byte
line ends with $0D
file ends with $40
2. Assm/Ted by CW Moser starts with line number $10 $00
end of line is high bit set
There may be rare situations that a file starts with a $0D or a different line nr. You can force CW Mose detection by changing this to a sequence of $10 $00 $0D and if necessary blanks $20 to make it consistent. If in doubts: use an editor that shows the file in hex (Ultra Edit, or the free Notepad ++, Text editor PRO) and study the tape file.

Methods to get the binary file out of a Junior or KIM-1.
Read the record tape into a binary with Ed’s KIMTAPE conversion *see below). It is MS-DOS and runs fine in VDOS ( or DOsbox (slow).
Make a note of start address as shown by KIMTAPE.
Non-printing ASCII characters are filtered out of the resulting text file.

KIM Tape Convert WAV to BIN and BIN to WAV

Not my program, but so handy!

KIMTAPE v0.5 – tape conversion utility for KIM-1 and SYM-1 (2004-05-17) Local copy of

KIMTAPE allows programs stored on cassette tape to be decoded to a program file. It handles both MOS Technology KIM-1 and Synertek SYM-1 tape formats including HYPERTAPE. The reverse process – converting a program file to an audio wavefile is also possible, allowing one to produce perfectly regenerated cassettes. KIMTAPE works with 8-bit mono WAV, VOC or RAW audio files recorded
at 22050 samples per second.

Download: (MS-DOS) It is MS-DOS and runs fine in VDOS ( or DOSbox (slow).

The binary files in the KIM-1 program archives have been reproduced, from the original cassette recordings, with the tool KIMTAPE on a PC in a DOS box. See Eds DX-Forth and Utilities Page for this and other nice programs.
This program also makes it possible to reproduce the original cassette recordings that can be read by a KIM-1.

The files were made as follows: The KIM-1 cassette audio was connected to the PC audio input and (with e.g. Audacity) recorded as a wave file (mono 22KHz).
For example: qchess.wav
The wave file was then converted with KIMTAPE to a binary file (the exact content of of the KIM-1 memory when recorded).
And the KIMTAPE utility then displays load address (for example and tape ID

c:\kimtape qchess.wav qchess.bin
KIMTAPE version 0.5 17-May-04
infile: qchess.wav
outfile: qchess.BIN
Program 01 address 0200 checksum OK xxxx bytes done

This .bin file (any extension is fine!) is NOT a wave file! It contains the exact content of the KIM-1 memory when recorded. The size is exactly the number of bytes as stored in the memory of the KIM-1 and much smaller than the wave file. This binary file can be converted back to a wave file with KIMTAPE or converted to a papertape file with KIMPAPER:

C:\kimtape -M -A0200 -D01 -B2 qchess.bin qchess.wav 

As you can see: you have to specify the load address and the program ID. The B parameter indicates hypertape speed (2 here, slow)
The resulting wav file should be acceptable for the KIM-1. It is (as I have tested) acceptable as input for KIMTAPE!

All command parameters can be seen by typing KIMTAPE without parameters:

Pascal-M Cross compiler

Executables of cross compiler, workflow, sources, command line utilities.


KIM-1 Software

On this page my collection of KIM-1 software in binary format , manuals and articles, from my tapes and scanned paper archives and user contributions.
Most require an expanded KIM-1 with RAM memory above $2000, 16K recommended. Of course the Micro-KIM and the Corsham KIM Clone and the PAL-1 with memory expansion have enough horsepower to run this.
See the page for useful programs to convert binaries to papertape etc.
Not all have been tested, some use non-standard TTY I/O routines, so study, test, experiment and have fun!

KB-9 and KB-6 are the name used for the Microsoft Basic for the KIM-1. One of the 6502 family of early interpreters by the then called Micro-soft company. KB stands for KIM Basic, the 6 and 9 for the precison of digits.
See here for the page about the KIM-1 binary versions , articles, listing, sources and build-and-enhance- it-yourself version.

Focal-65 V3D

The FOCAL programming language Version 3D (26 aug 1977) for the KIM-1.

A small interpreter (about 5K) for a convenient interpreted language. Floating point 9 digit accuracy. Two versions were distributed, one by Aresco and another by the Program Exchange. Included was a source listing, which I do not have.
Requires memory from $2000 and up. May have some terminal echo problems, see below in User Notes 13.
Based upon the DEC FOCAL8 language for the PDP-8, as defined in the Manual DEC-08-AJAB-D.
Programmed by the 6502 Group , read here the background of the creation of FOCAL-65.
Program and manual
The scanned manual, Aresco version
Disassembled source by Paul R. Santa-Maria
Introduction to FOCAL (dutch, KIM Kenner) by J. Janssen page 1, page 2 and page 3
Introduction to FOCAL, 6502 User Notes 12
Improve on echo problems with KIM TTY, from 6502 User Notes 13
Make room for enhancements, extend to 8K, from 6502 User Notes 14
Speed it up, from 6502 User Notes 15
Cassette save/write an LED display listing, from 6502 User Notes 16
Move FOCAL 65-E into EPROM page 1, page 2, from Compute II Issue 3


The FORTH language 6502 FIG-FORTH

Binary Forth original, start at 2000
FORTH assembler sources, 6502, 65C02
Fig-FORTH 6502 manual
Fig-FORTH Manuals May 1979

Tiny Basic

Tom Pitman’s Tiny basic. Small enough to fit in th 1K KIM-1, yet a real Basic interpreter

Tiny Basic binaries,
low memory version is tiny3, load address 0000 start address 0200
high memory version is tiny 1 load address 0000 + tiny3 load address 2000, start address 2000
Tiny Basic manual as pdf
Tiny Basic manual as html
Tiny Basic manual as text file
Tiny Basic Experimenters kit as pdf
Tiny Basic Experimenters kit as html
Tiny Basic Experimenters kit as text
Getting the most of Tiny Basic.pdf
Articles on tiny Basic from 6502 User notes
Source of Tiny Basic, monitor, and Tiny Basic Bill O’Neill
Tiny Basic for CC65 assembler sources
Tiny Basic games, such as adventure
Games for Tiny basic from Dr Dobbss Vol 1 Page 1, Page 2
Articles from the dutch KIM user Club:
KIM Kenner 10 Tiny Basic, tips how to save and load and change prompt, Hans Otten.
KIM Kenner 23 Tiny Basic, Filip van Kenhove, adapt to Elektor Junior


COMAL is an interpreted structured language. I have only as original the KIM User Club Elektor Junior version, and as with most of the 6502 SBC programs, not that difficult to adapt to a KIM-1, as shown in the last pages of the manual (in/out/break character, load/save tape, memory layout).
KGN COMAL binary
Manual KGN COMAL (dutch)
COMAL Introduction

MICRO-ADE assembler/editor

Updated November 2021

MICRO-ADE was the working horse for many KIM-1 users, the small and powerful assembler/editor/disassembler written by Peter Jennings, Microware.
Manual and program are placed here with permission by Peter Jennings to the KIM Club (thank you Peter for this and for a great program!)
A letter sent by Anton Muller, KIM User Club the Netherlands, to Peter Jennings, thanks Peter for the scan!

In August 2021 I (Hans Otten) typed in the source of MICRO-Ade from the listing in the manual, the output is binary compatible with the binaries I saved from tape and are tested on the KIM-1.
The result is a source identical (in standard MOS Technology assembler format) to the listing and binary identical to the page image. I also made new high quality scan of the manual and the listing.
Micro Ade program source and binary
Scanned manual
Scanned listing

Read in the KIM KENNER archive the source of the enhancements (text by S.T. Woldringh o.a.)
The KIM club enhanced Micro Ade to version 8. Download here the binary with a 2 page command summary.

Microchess for the KIM-1

Updated November 2021

MICROCHESS for the KIM-1. Another Peter Jennings Microware product. Runs on a standard KIM-1. Control via LED displays and hex keypad. Quite a commercial success, many sold!

Wave files of tape and binaries, dump of my cassette files
Assembler source and binaries, typed in by me in 2021, binary identical to tape
Original manual (from the reseller The Computerist) scanned by me
Original manual by Peter Jennings
Manual in HTML format
Article on upgrading/extending Microchess, Compute II Issue 1, pdf format
Article on upgrading/extending MICROCHESS, Compute II Issue 1, html format
Upgrade/extending assembler source and binaries, typed in by me in 2021
More chess openings, Fer Weber 1978

6502 Macro Assembler and Text Editor CW Moser

CW Moser ASSM/TED Assembler and Text Editor binaries: original, KIM-1, Elektor Junior
Manual scanned in PDF format

Color version of later manual
Dissecting C. W. Moser’s ASSM_TED, Compute! Issue 11
Commodore PET version of the manual
Graphics Drawing Compiler for PET and SYM manual
Fast cassette interface for ASSM/TED by CW Moser
Universal 6502 Memory Test PET, Apple, Sym and Others, Compute! Issue 1

KIM Tape Copy v1.1

kim tape copy v11 KIM Tape Copy v1.1, copy all files on a KIM cassette. Uses two recorders attached as shown in the Micro Ade manual.
Source in Micro Ade format
Listing of Tape Copy

H14 printer and parallel keyboard routine

The Heathkit H14 printer is a simple matrix printer with a serial interface. This routine allows to use this printer via two pins at the free 6530 PIA port, see circuit diagram. Resistors are 2k2 ohm.
H14 printer and parallel keyboard input assembler source
Lsiting and crcuit diagram

Printing disassembler

Printing disassembler, load and start address is $B000
Source of disassembler
Requires a parallel keyboard for character input at the free 6530 PIA port. H14 printer output if print is requested. See above for the H14 printer routine.

Q-Chess for the KIM-1

Q-Chess for the KIM-1. Requires 8K memory and a TVT-6 display. Via ptaching a TTY can be used.
Manual, including TTY patches
Binaries of Q-Chess for TVT-6 and for TTY
Patches on Q-Chess by Fer Weber, De 6502 KENNER 17 – augustus 1981

Usurpator Chess for the 6502

Usurpator Chess for the 6800 and 6502 in 2K, a book by H.G. Muller
The book, with source listings for 6800 and 6502
Source in CW Moser format


Time your reaction. Standard KIM-1 LED display and keypad. Source included.

First Book of KIM sources

The First Book of KIM-1 in PDF format
The First Book of KIM-1, part in text format
The First Book of KIM-1 in HTML format
Sources of The First Book of KIM-1 in source and papertape format,
Jeff Tranter
Software from First Book of KIM in binary, audio (Wave) and papertape format, by Dave Willams.

KIM Venture

A (tiny) Colossal Cave adventure for the KIM-1 by Bob Leedom


HEXPAWN, a game for the KIM-1 by Robert Leedom


Baseball, a game for the KIM-1 by Robert Leedom

Telefonbuch Hobbycomputer #1 Herwig Feichtinger

Telefonbuch Hobbycomputer #1 Herwig Feichtinger


Pascal-M: A full (1978) Pascal P2 descendent compiler system for the KIM-1.
See the School of Wirth pages for more information, including sources and binaries

Pocket calculator for the KIM-1/h3>

Siep de Vries Westvries Computing The Netherlands

1977Simple calculator (integer 6 digits positive) + – / *
I/O via TTY or keypad/LED display, the same method
as used by the KIM-1 monitor.
Two versions (scans included):
a special publication from the first days of the

KIM Club in a traditional 6502 assembler

and a later version for the Micro ADE assembler editor.
Sources included of both versions (TASM 32),

with resulting listing and papertape and Intel hex files.
As close to paper original, changes due to assembler quirks.
Download here Sources, papertape, listings, original scans


Elektor Elektuur Junior

Elektuur/Elektor and the Junior Computer and other 6502 based machines.

The Junior computer design was published by Elektuur/Elektor from 1980 on. It was published in a series of magazine articles, four books and several socalled paperware A4 booklets. Loys Nachtmann designed and developed the the Junior Computer. G.H. Nachbar did the Dutch translation of the German books. The 4 Junior books were translated into English, German, Spanish, Italian and French as well.

The Junior design is in fact heavily inspired by the hardware of the KIM-1 (or call it a clone ..), the floppy interface design is based on the Ohio Scientific OS65D design. It was delivered as a kit or could be be built from only the PCB’s sold by Elektuur. Many hobbyist have build one. Later extended with an adapted version of the 8K KB9 Basic and even a disk operating system (Ohio Scientific DOS OS65D).
Articles in the Elektuur magazine and books (1-4), a 6522 book in the same series, in Dutch, English, French and German have been published.

Quickly adopted by the Dutch KIM Gebruikers Club because it was so close to the KIM-1. In the later days the number of Junior Computer users exceeded the KIM-1 users and changed the nature of the club from professional users to a hobby club. It also led to the DOS65 operating system for the Elektuur 6502 CPU board

The magazine Elektuur (the Dutch name) and Elektor (the name in many European countries) surprised us in 1980 with the publication of a build-yourself 6502-based SBC. It is a design in the tradition of the KIM-1 and SYM-1: a hexadecimal keyboard, six hexadecimal led displays and KIM-1 compatible tape format.
Many Junior Computers were built, either from the PCB made by Elektuur and separate components or as a complete kit. And after we (Anton Muller and me) sent a letter to the Elektuur magazine that got published about the KIM Gebruikers Club, many hundreds Junior users joined the club.
The developments after the Junior design in Elektuur led to the EC65(K) (see the Elektor Computing books) and the KIM Club DOS65, documented on this page.

What you can find here:

Radio Bulletin

The dutch magazine Radio Bulletin (RB, RB Electronics) has a long history, going way back to the early years of electronics. The name was derived from what electronics meant for amateurs in these days: building radios yourself.
It was published by Uitgeverij de Muiderkring, a publishing company in the Amroh group of companies.

The magazine was published in large volumes in the years 1970-1985, due to the popularity of do-it-yourself electronics and audio. Also the beginning of the microprocessor revolution was adequately covered and the great years of the hobbycomputers 1980-1990 were contributing to the success. Besides the magazine Uitgeverij de Muiderkring published many books on electronics. After 1990 the success faded and the magazine left the mass market and stopped in 2003. The publishing company Uitgeverij de Muiderkring, together with Amroh, went bankrupt in 2002 (I lived closely to the last location and saw the empty offices when passing by).

In 1977 Dick de Boer joined the staff of RB and introduced the readers to microprocessors and in particular the 6502 and the KIM-1. Also the KIM Gebruikers Club and the HCC were founded that year and RB started to write articles about all this exciting new developments!
I was then already a freelance writer about electronics but Dick made me study the microcomputer such as the KIM-1 and made me join the KIM
Gebruikers Club and the HCC (member 760 member). Dick de Boer, his successor Paul de Beer and me (Hans Otten) and others wrote many articles about the KIM-1 and related 6502 based systems for Radio Bulletin. Especially Dick wrote good introduction articles and developed sophisticated hardware and software like a graphical display. After leaving the magazine he became a software engineer and helped me also to my first job as software engineer in 1980. Me and Paul de Beer concentrated more on expanding 6502 systems like the KIM-1 with memory (RAM, ROM) and I/O cards like PIA, VIA and ACIA and mass-storage such as the Mini Digital Cassette Recorder. The bus of this expansion system was the so called BEM-bus.

I did translate a book Computer Interfaces by Owen Bishop for de Muiderkring to dutch. A scanned version is presented here.

All these articles are downloadable here, as they describe my publishing history and my KIM-1 system, designs by us of which the prints sold quite well. As you can see in the long list of articles the KIM and the 6502 played a major role in the microprocessor revolution starting in 1977 and lasting until 1987 for me.

What you see about Amroh, Uitgeverij de Muiderkring and Radio Bulletin is:

Selection of my and others articles 1977 – 1987 in Radio Bulletin
the RB Specials
the Cosmicos 1802 CPU based system by H.B. Stuurman, book and articles
some bits about the long history of Radio Bulletin
Elektronica ABC, the diy magazine

See also:

– Dr Blan articles on Step-by-Step radios
– Step by Step radio by Amroh