(information and design by Norbert).

Cassette interface for the Micro-KIM.

With small changes Norbert took the circuit described in the 3rd book of Elektor Junior computer. The +12 V problem he solved taking a LT1073 dc/dc converter to generate this voltage. Everything is working fine: Micro-KIM is connected to the soundcard of the computer to store and reload programs.

N39 is needed because there is not a port present or reachable on the Micro-KIM board, so it takes 1/4 74LS01. With a pullup resistor of 3k9 connect the unused inputs to +5V, so the whole thing will not oscillate.
For the +12 V generation a LT1073 CN8-5 was used. The diagram is shown on page 12 of http://www.datasheetcatalog.com/datasheets_pdf/L/T/1/0/LT1073.shtml (5V to 15V Step-Up Converter). It is important to use exactly the values of the resistors (metal oxid series) shown there. The LT1073 CN8-5 is presently still available for 4,20? at www.reichelt.de . They also have got the LT1073 CN8, but it did not work in this context. The no-load voltage measured at the output of the LT1073 is much higher (arround +40V) than the desired +12V. But with load it reduces to about +11.8 V and remains constant there. A 12V/1W zener diode protects the 12V output of the LT1073.

Dave Williams designed, build and sold MOS KIM-1 Reproduction boards. A real KIM-1 clone! The goal was to reproduce a KIM-1 as exact as possible.
So the MOS KIM-1 Reproduction board has the same dimensions, same connectors and as much as possible the same components, including the audio cassette interface, 1K RAM with 8 2102 SAM ICs. The keyboard is reproduced with the same layout and looks quite identical. Components types are chosen close the the originals (though the KIM-1s went to many revisions with varying looking components) and placed on the same location.
The CPU is of course a 6502 at 1 MHz crystal clock frequency. The edge (Application and expansion) connectors are physically and logical identical.

Since 6530 RRIOT ICs (the 002 and 003 variant) are not available anymore, the same solution as in the other clones is chosen: a 6532 RIOT with a 2K EEPROM and some logic ICs (3) to get a hardware solution that makes it look exactly the same for the KIM-1 ROM software. The PCB is a new design, not the typical 70ties KIM-1 design.

The result is great: it feels, looks and operates as an original KIM-1. First Book of LIM programs run, Even Microsoft KIM-1 Basic and Microchess run, when additional RAM is connected.

Documents (thanks to Dave Williams!)

	MOS KIM-1 Reproduction Board Layout
	MOS KIM-1 Reproduction Schematic
	MOS KIM-1 Reproduction BOM

I added the Corsham Technologies KIM-1 60K RAM/ROM board and the KIM I/O board, which makes it a great system!

With the MOS KIM-1 Reproduction comes a small edge connector PCB for audio and power connections. Alas no TTY connections and keyboard/TTY switch. On an USB stick the well known KIM-1 documentation (all also found on this site!) and the First Book of KIM programs, as typed in by Jeff Tranter in papertape format, also found here. But as extra the programs as KIM-1 audio files are provided, as WAV files, ready to load into the KIM-1.

MOS KIM-1 Reproduction	Original KIM-1 rev F
MOS KIM-1 Reproduction	Original KIM-1 rev F

Some photos from Dave Williams, showing the KIM-1 Reproduction connected to an audio cassette recorder, a KIM-1 S-100 Motherboard with a RAM card, running Microsoft Basic KB9 and a production line of KIM-1 Reproduction (with a real KIM-1 in the top row!)

My MOS KIM-1 Reproduction will be connected to Corsham Technologies cards: SRAM and EEPROM and I/O card

Corsham Technologies KIM-1 RAM/ROM and I/O board connected to a KIM-1