website/content/museum/heathkit-zenith-et-3400.md

title, categories, types, origins, years, cpus, params

title	categories	types	origins	years	cpus	params
HEATHKIT / ZENITH ET-3400	Computers	Home Computer	U.S.A.	1976	Motorola 6800 then 6808	name image company company_name specs tabs forum_thread photos emulators links oc_id source ET-3400 /media/museum/photos/heathkit_et3400_system_s1.jpg /companies/heathkit-zenith HEATHKIT / ZENITH label value NAME ET-3400 label value MANUFACTURER Heathkit / Zenith label value TYPE Home Computer label value ORIGIN U.S.A. label value YEAR 1976 label value BUILT IN LANGUAGE Monitor in ROM label value KEYBOARD 17 keys Hexadecimal keypad label value CPU Motorola 6800 then 6808 (1981) and 6802 (1987) label value SPEED 1 MHz label value RAM 256 bytes expandable to 1 KB label value ROM 1 KB label value TEXT MODES 6 x 7-segment LEDs label value SIZE / WEIGHT 30.5 (W) x 30.5 (D) x 10.15 (H) cm. / 2 Kgs label value POWER SUPPLY External AC adapter label value PERIPHERALS Prototype area label value PRICE $199.95 Kit, $279.00 assembled, $99.95 for the ET-3401 course photos emulators links 766 title subtitle text image LARGE VIEW #1 At power on or after a Reset, 'CPU UP' is displayed. /media/museum/photos/heathkit_et3400_system_s2.jpg title subtitle text image LARGE VIEW #2 /media/museum/photos/heathkit_et3400_system_s3.jpg title subtitle text image REAR SIDE No connectors and no ability to save typed programs to a tape recorder. /media/museum/photos/heathkit_et3400_rearside_s1.jpg title subtitle text image MAIN BOARD The upper part of the main board is covered by the case. /media/museum/photos/heathkit_et3400_mainboard_s1.jpg title subtitle text image MAIN BOARD CLOSE-UP Each area of the circuitry is clearly marked. /media/museum/photos/heathkit_et3400_cloeup_s1.jpg title subtitle text image PROCESSOR CLOSE-UP Here a 6802 version /media/museum/photos/heathkit_et3400_proccloseup_1.jpg title subtitle text image OPENED A crude power supply unit is fixed to the hidden side of the main board. /media/museum/photos/heathkit_et3400_opened_s1.jpg title subtitle text image MANUALS The ET-3400 was delivered with a full set of manuals and tests:\ - Microprocessors flipchart,\ - Two Assembly Language Programming Workbooks,\ - An hardware assembly manual,\ - A ten chapter reference book,\ - Two audio cassettes,\ - Two final exam kits(assembly language test and microprocessor test),\ - A poster sized schematic of the computer,\ - A parts pictorial illustration booklet. /media/museum/photos/heathkit_et3400_manuals_1.jpg title url platform text ET-3400 simulator http://www.pilgrimworks.com/trainer.htm Windows title url text Heathkit ET-3400 Resources (Yahoo Groups) http://tech.groups.yahoo.com/group/ET-3400/ Modifications, schematics, manuals and other resources for the Heathkit ET-3400 Microcomputer Learning System. 785 url date https://web.archive.org/web/20230510155752/http://www.old-computers.com/museum/computer.asp?c=785 2023-05-10

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.

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Mendel Cooper's memories:
I built one of these from a kit back in about 1984, I guess. Price was approx. $200 in kit form.
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.

We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.