The Heathkit/Zenith MicroComputer Learning System model ET-3400 was a very popular item designed to teach principles of computers and programming at Universities in the 1970s., and to educate the students of internal computer hardware and software components by self-assembly and programming the machine in pure Hexadecimal language.
It was delivered in assembled or Kit form. It also featured a prototype area and could be used as a design aid for developing special interface circuitry with common 6820 parallel interface or 6850 asynchronous chips.
Several software in ROM were also available. Among them an Assembler and a Tiny BASIC.
Heathkit used to sell three educational courses based on the ET-3400:
1) Microprocessor Course, EE-3401
2) Microprocessor Interfacing Course, EE-3402
3) Microprocessor Applications Course, EE-3405
Using the specs in the manual, it was pretty easy to build homebrew memory expansion. For a couple of dollars worth of parts, I built a 2K module, using a 6116 (2K x 8) static RAM chip.
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NAME | ET-3400 |
MANUFACTURER | Heathkit / Zenith |
TYPE | Home Computer |
ORIGIN | U.S.A. |
YEAR | 1976 |
BUILT IN LANGUAGE | Monitor in ROM |
KEYBOARD | 17 keys Hexadecimal keypad |
CPU | Motorola 6800 then 6808 (1981) and 6802 (1987) |
SPEED | 1 MHz |
RAM | 256 bytes expandable to 1 KB |
ROM | 1 KB |
TEXT MODES | 6 x 7-segment LEDs |
SIZE / WEIGHT | 30.5 (W) x 30.5 (D) x 10.15 (H) cm. / 2 Kgs |
POWER SUPPLY | External AC adapter |
PERIPHERALS | Prototype area |
PRICE | $199.95 Kit, $279.00 assembled, $99.95 for the ET-3401 course |