The Heathkit ET-3400 is a self-contained microprocessor training system based around the Motorola 6800.

Model   CPU   Introduction   Static RAM   Memory
ET-3400   6800   1976   256 bytes   4 chips
ET-3400A   6808   1981   512 bytes   2 chips
ET-3400A   6802   1987   512 bytes   2 chips


In addition to the hardware, Heathkit put together several training courses:

  • Microprocessor Course, EE-3401
  • Microprocessor Interfacing Course, EE-3402
  • Microprocessor Applications Course, EE-3405

There was also an add-on unit called the ETA-3400 Memory I/O Accessory, which added a more comprehensive debug monitor, BASIC language programmability, and a serial port (to attach to a "dumb" terminal).

I am interested in any hardware or documentation for these machines that you might have. If you would like a good home for your old Heathkit microprocessor equipment, please send me an e-mail.

The following are titles and excerpts from manuals related to the ET-3400:


From Bob Furtaw (Manager of Heath Service Publications and Training, later the Manager of Heath User's Group):

I worked at Heath company. When I designed all the experiments for the ET3400 course while there, I did them all on a Motorola EXORciser and a TI Silent 700. When the course manual was printed, I insisted that the Assembly and Machine code be photo copied directly from the Silent 700 pages so there would be absolutely no mistakes in the process. In later trainer revisions however, the pages were translated by humans so the print would show up better in the final manuals. The person in charge of the manual department didn't like the dot matrix print and reset all the pages without my knowledge.

Another piece of trivia - before the ET3400 was ready, I did most of the experiments on an EPA Associates computer. Then, I ported all the software over to the ET3400 and finished the final few experiments. There were about 10 times the experiments created than the ones that finally made it to the final manual.

Comments to Dan Veeneman

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Updated March 28, 2017