The design of the Elektor Junior is well documented in the Elektor articles, books and other articles like the KIM Kenner. In many languages, the archive here is as complete as possible, but you could see some pieces of information in only one language section. The hardware components for the most part are not exotic, especially for the time of publication.
The software in the form of (sources of) the ROMs and applications such as Microsoft Basic and even Operating systems like OS65DV3 is also easy to find.

So with all this information available it is no surprise to see modern versions of the Junior. Some try to stay as close to the original design, others just take the ideas and implement it in a more modern an d convenient way.

Some obstacles in building a Junior are:

• the original PCB’s are only available as low quality magazine articles quality. And even then be careful, the original article mixed up front an back!
• the EPROM for the Junior monitor is a 2708 UV EPROM. A very old hard to get part, hard to program and requiring power supplies like -5V and +12V besides to usual +5V.
• the expansion card used a 82S33 PROM for the address decoding. Also an obsolete part and hard to program.

What designers can do:

• design the PCB’s again. Kicad e.g.
• replace the 2708 with an EPROM like the 2716 or bigger or an EEPROM like the 28C16 or bigger
• use a GAL or discrete logic for the 82S33 on the expansion board
• use a modern SRAM IC and increase RAM memory a lot
• modify the address decoding to fit the modern ROM and RAM
• obtain parts like the 6502, 6532 and 6522
• replace the hard to get 1 MHz crystal with a can oscillator
• simplify the power to +5V

Here are some examples of builds:

• Junior by Philippe Roca
• Junior Computer Replica by laurent-fr
• Junior PCBs by Werner Beukes
• Junior revival Bram Prosman
• Philippe Roehr on KB9 and OS65DV3.3
• Junior Computer ][

With thanks to Philippe Roehr from France I present on this page how he got KIM Basic 9 and Ohio Scientific OS65D to work on the Junior

Junior build

Philippe has build a Junior system with at least a main board, an expansion board, 16K Dynamic RAM board expanded to 64K and a floppy controller.

It started with the Junior itself, followed by the expansion card, The monitor software PM and TM were tested.

Floppy controller, RAM card behind.

Junior KB9 Basic

Philippe started with the KB9 binary from the KIM-1 pages.
Philippe then applied the process outlined in the Elektor articles to adjust Basic to the Junior character I/O routines and also improved the speed by adjusting the now unnecessary code that took care of the ROR bug in early 6502’s.

Philippe transferred the binary to the Junior with Ed’s utility KIMTape, producing a KIM-1 audio wave file. The Junior accepts this format, a bit slow but only needed once. After seeing all was well, Philippe wrote the now optimized Junior KB9 Basic to audio wave file, and made a hex dump on the terminal. I picked up the dump, a captured text file form a a terminal emulator, and wrote a conversion program to produce a binary.

All the files here: archive with audio wave file, dump on terminal, binary and conversion software.

OS65DV3.3

After building the Junior, having PM and TM monitor working well, KB9 Basic operational, the next step Philippe took was getting the operating OS65Dv3.3 operational.
He took the steps described by Elektor in the articles with some modern additions.

A Junior able to run OS65DV3.3 needs an expansion card,  a RAM card (his is 64K) and the Elektor floppy controller, which is identical to the OSI one (6850 + 6820 ICs)

Instead of a real floppy drive Philip used the hardware Gotek floppy emulator with the Flashfloppy firmware. And used the manuals images of http://osiweb.org, and the OSIHFE utility described in the OSI Web forum posts.

Elektor made a bootstrap eprom (ESS515 download here, source in Paperware 2) able to
* load OS65D (V3.1 or 3.3 as far as I know) from floppy
* give basic I/O capability (RS232 and floppy)
* manage hex display and keyboard
* modify OS65 for the hex display after the very first load to fully adapt them to the system ( about 10 bytes to modify)

Here the OS65DV3.3 disk image in native and Flashfloppy format ready to use.

During the second part of december 2020 Philippe added a real floppy controller and added the Ascii Video Terminal (new version of hackaday). With improved moter control of the floppy drive!

VDU board with OS65D

PMV for OS65D source checked by Philippe Roehr
PMV for OS65D ROM

Elektor did write about the Junior and related designs in recent years, retro electronics! This site (at the present and previous wwww locations) was mentioned also.

Oh, and this is retro and has the name Elektor Junior but it is not a Junior computer!

6502, Junior and EC65(K)/Octopus publications by Elektuur and Elektor 1978 -1985

	Books and Paperware Junior Computer, Elektor Computing 1-5: Nederlands English Deutsch Francais Italino
	Articles from the magazine Elektuur and Elektor 1978 -1985: Nederlands English Deutsch Francais Italino
	The dutch KIM/6502 Club published many articles on the 6502 and the Junior: All Junior related articles here. The whole archive is here: KIM 6502 Kenner archief

Software for the Elektor Junior, if adapted, runs on the PM version of the system software, using the bit banged serial TTY I/O on the Interface card.

You find system software, such as ROM binaries, TM, PM etc with sources in the pages at Junior Elektor, from base to full system

On this page:

KB9 Basic
MICRO ADE
Tiny Basic
Comal
Microchess

ASMM/TED by CW Moser
Forth-79
Usurpator Chess
Various assembler sources as published in Elektor and the KIM Kenner
The Junior tapes

Microsoft KB-9 Basic V1.1

How to adapt KB-9 BASIC to the Junior

KB-9 stands for Microsoft BASIC V1.1 for the KIM-1 with 9 digits precision. Scanned manual The original KIM-1 KB9 Microsoft BASIC V1.1, binary and papertape KB9for Junior updated in BIN, hex dump and wave format All the files here: archive with audio wave file, dump on terminal, binary and conversion software. (See also Junior with KB9 and OS65DV3.3 – Retro Computing)

See the KIM-1 Software page for more information on KB-9 BASIC.

MICRO-ADE assembler/editor

Updated October 2022

	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.
MICRO-ADE V8
The Elektor Junior seems to be designed for MCIRO ADE: the Interface card has two relais to control the motor of an audio cassette recorder, just as MICRO ADE wants.
You see that the system software of the Junior (ESS503, the monitor, PM, TM, PME, PMV, Universal Terminal is written in the MICRO ADE dialect of assembler.

Tiny Basic

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

See the KIM-1 Tiny Basic page for more information on Tiny Basic, articles, binaries, sources, how to adapt to the Junior.

COMAL

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)
Partial commented disassembly of Comal

Microchess for the KIM-1

Updated October 2022

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!

Microchess has been adapted for the Elektor Junior by Sjaak de Wit, sjelabs.nl.
Description of the adaptation
Source and binary of Microchess for the Elektor Junior

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
Upgraded/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 (with appendix for KIM-1 adaptations)

Sources of CW Moser for 65C02 and Junior binaries
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

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 Binary Source in CW Moser format

Various sources in assembler

MICRO ADE, ASSM/TED format as found in the Junior tapes.
All sources from the Junior tapes: Elektor programs, sources of MICRO ADE, ASSM/TED, Fort, Universal terminal, Elektor clock 222, Basicode for KB9 and more.

Junior tapes

With a Junior I bought second hand came a little booklet and a floppy. The previous owner must have been a active programmer, and he had saved his tapes on disk, the audio files were converted to binary files. The dump program is included!
I copied the floppy over to my computer, and hand typed in the description form the booklet.
If the file was a program, the binary was just a representation of it.
Text files were not that easy. A hex dump showd it were text files with some editor related extra’s, e.g. line numbers.
The files were the tape dumps of the editors used on the Junior: MICOR ADE and CW Moser.
After studying the dumps I wrote a program to recreate the text in normal DOS format. A GUI version first, later a CLI to easily convert the text filen and give it the name of the file instead of the numbering scheme.
The archive is a treasure, with Comal, MICOR ADE, CW Moser ASSM/TED, Forth binaries and sources for Junior and KIM-1. Some ROM dumps were present. And many assembler sources in MICEO ADE and CW Moser format. Here I present you the original archive, and the name/text converted one.

Junior tapes

The Junior tape archive
The Junior tape archive, text files decoded, files with correct names
The KIM-1 tape to text program
(Command line and GUI, Freepascal source included to decode text files from the Junior.

Forth

The FORTH language 6502 FIG-FORTH

Binary Forth original, start at 2000
FORTH assembler sources, 6502, 65C02
FORTH assembler sources, 6502, 65C02 in ASSM/TED format, Elektor Junior binaries
Fig-FORTH 6502 manual
Fig-FORTH Manuals May 1979