The History of Personal Computers, Part 2: The Heathkit Story


The history of personal computer kits from Heathkit.

If you read my Part 1 blog (, you know that I developed a computer kit for McGraw Hill/NRI back in 1972.  I left MH in 1973 to go to the Heath Company.  I went there to start Heath’s education and publishing business.  And that I did with a launch of a line of self-study courses in electronics with kit trainers.  It was a great success with individuals and technical colleges.  However, I had in mind making a kit computer too.

Heath was not interested in creating a computer kit even though it offered two analog (yes, analog) computer kits using pluggable vacuum tube amplifiers.  However, the discussion and consideration of a computer kit was on-going.  The first effort was to define an educational product, a microprocessor trainer and course based on the Motorola 6800.  That worked out well as with microprocessors being new to electronics there was an overwhelming need for education in this new field.  The ET-3400 was the result and it was a huge success.

Later, in 1975 we decided to do something about a more formal computer kit given the success of MITS and others with kit products.  So in addition to my education product duties I took on the job of defining a product line with the help of Heath Manager of Design Engineering Chas Gilmore.  With minimal in-house computer expertise, we decided to try to buy a design and “kit” it.  We tried with Apple and were rudely turned down by a young Steve Jobs.  We tried with the minicomputer giants Digital Equipment Corporation (DEC) and Data General both of whom said no.  DEC eventually agreed.  So we decided to make our own. The result was two computers, a video terminal, a paper tape reader/punch and a printer.

The main computer was the H8 based on the 8080 as were most of the earliest kits.  The second was the H11 based on Digital Equipment Corporation (DEC) 16-bit LSI11.  The terminal was called the H9 and the paper tape peripheral was the H10.  The H8 had sloping front panel with a numerical keypad and LED display.  Data entry and display was in octal.  Yes, octal and not hex as it probably should have been.  You can see how we were influenced by the DEC computers as some of us had PDP-8 and/or PDP-11 experience.  Anyway, the H8 had a 4KB RAM using Motorola’s 1K static RAM chips.  We had to fly to Motorola in Austin to beg for our allotment of RAM chips to make production.   The static RAM cost more than dynamic RAM at the time but it avoided the horrible problems that MITS and others had with DRAM.  The I/O was an audio cassette interface.

The H9 terminal had a standard keyboard and 12-inch mono CRT with 12 lines x 80 characters and an RS-232 interface.  The H10 reader/punch ran at a blazing 10 cps.  It did not sell well as everyone used the audio cassette interface instead.  It was a dumb idea in retrospect.

The H11 came along later as DEC agreed to supply their LSI-11 in prewired form and provided a license to distribute their RT-11 operating system.  The H11 had a dual 8-inch floppy drive accessory.  The whole thing was expensive but after all it was almost a minicomputer in kit form.  Few appreciated this at the time.

As for software we tried to get CP/M from Gary Kildall but he said no.  We tried to get Microsoft BASIC but we decided against it.  Bill Gates visited Heath and said we could use it for an outrageous per license cost.  He was arrogant and discourteous and our president at the time Dave Nurse kicked him out.  We ended up hiring our first real programmer who wrote both an OS and a version of BASIC.

We launched the computer line in 1977.  It was an instant success despite the competition from the Apple II and TRS-80 which also launched that year. Within a year we were making $40 million annually with computers putting Heath Company well over the $100 million revenue mark.  We followed up with floppy drives for the H8 and an all-in-one computer called the H89, a terminal and floppy in a box using a Z80.  It too was a huge success.

In 1979, Heath parent company Schlumberger sold the company to Zenith.  Zenith wanted a way into the computer business.  They took the computer product line away and created Zenith Data Systems.  The Heathkit business continued in the kit mode.  ZDS sold the H89 and went on to define a line of 286 and 386-based computers in the following years.  ZDS was ultimately sold to a French company Groupe Bull 1989 and later to Packard Bell.  Once the IBM PC came along in 1981, the remaining company tried to compete but could not and ultimately folded.

With the sale of the computer product line to Zenith, I became VP of the educational business which had grown to about $15 million in the meantime.  I expanded the line by defining and developing Heath’s robot kit called HERO.  It too was a huge success.

The Heath kit business and related businesses folded in 1992 after several acquisitions but the educational products business called Heathkit Continuing Education soldiered on until 2012 when it finally faded away into bankruptcy. 

There have been rumors of Heathkit returning from bankruptcy.   Those behind Heathkit must be planning a return as their website offers a survey to find out what potential customers want in a kit.  I suspect if they do return Heathkit will focus on amateur radio products and beginner kits.  That once famous name is no longer recognized or fondly remembered by the younger generation.  It will be interesting to see what happens given the rejuvenation of a whole new DIY movement today.  I wish them well.

Discuss this Blog Entry 12

on Dec 31, 2013

Although Heathkit figured prominently with Ham Amateurs and Audio Hobbyists its influence on computing was non-existent. Heathkits later kits (including logic based) were poorly thought out and did not sell well hence the failure of the company.

on Jan 8, 2014

Hey shjacks45 , What's with all the hyper negative comments in nearly all of your blogs ?

on Jan 7, 2014

I have to disagree with shjacks45. I built a number of Heathkit Amateur Radio, audio and test equipment kits. When they came out with computers I got the H89 and later their PC XT clone. I thought both products were very good. As a reference, I worked for two different computer manufacturers during this time.
It was economics that killed Heathkit. You could save a lot of money with a kit when the manufacturers did all of their assembly by hand. With automation that edge was lost, and the cost of supporting kits got higher. As ICs became more complex the average builder could not fix their assembly errors or isolate bad parts with just a VOM.
Computers were even worse than the ham and audio market. The market for computers by businesses, schools and everyday people was so huge that it drove the manufacturing costs to the point where it probably cost more to make a kit than it did to assemble and test a computer.

on Jan 8, 2014

Thanks for the story, and thanks to garysxt for his perspective.

My perspective on consumer electronics kits started with the vacuum tube era of High Fidelity during 1950's. Heathkits were great education in how MANUAL assembly could be performed, with some rework and struggles, by teens with no training on anything except a soldering iron. But I moved on to Fisher kits for FM. My roomate in college built his own 1 KW SSB amateur radio equipment (1955) and we were able to reach Sidney Australia from the dorm in Pittsburgh with a wire from the dorm window to the nearest light pole, and we "tuned for maximum smoke" as they say with me hanging out the window with a flourescent tube while he adjusted the "thingies" that peaked the output. Megafun.

But in EE classes, those days emphasized 60 cycle power systems, except for one lab where unknown devices were characterized with simple instruments...and the thermistor really hooked me on solid state devices.

So instead of power plants or steel mills, I ended up at Westinghouse on early power SCR's and in 1959 on the very early IC R/D, building a series of "DIY" tools like Epitaxial reactors, lithography coating, developing, align and expose tools (no vendors at first) as we launched the IC manufacturing era, with more and more automation made possible by the very chips we were making, Of course by 1970's the equipment vendors took over the tool making in most cases, although Motorola still made their own test systems, handlers and other Power and IC test systems globally until late 1980's. So the DIY experience with early Heath and Fisher kits launched a generation of DIY process and test system innovators and in-house equipment engineering shops at all major semiconductor companies. Calculators, watches, and later..COMPUTERS evolved from that industries efforts to control its processes and test systems to great extent, and IBM was, you may know, the largest semiconductor manufacturer in the world for many years,continuing that synergy between manufacturing processing, control, communications and test system DIY efforts, to the current "all vendors" supply chain. Bell Labs, similarly, the inventors of the transistor and early chip making, created great computers and languages to support their manufacturing, but we not allowed to SELL them due to regulated monopoly systems that left that job to IBM who was not allowed to make telephones it seems. Bell Labs DIY culture may have been helped by the many college physics labs that encouraged students to construct their own experimental setups, but they in return taught those colleges how solid state devices worked, and they helped many early chip making vendors get into the business.

Thought this perspective might help in the "history" blog world.
San Jose Computer Museum is of course a great source of inputs. Thanks for kicking off this part of the story.

on Jan 8, 2014

The Heath/ZDS Z-110 and Z-120 systems won the USAF Desktop 1 contract. This was a major turning point in the demise of Heathkit. The Z-286 won the USAF Desktop 2 contract. The Z-171 (the Morrow Pivot with ZDS enhancements) won the IRS over the IBM laptop. At this point, Zenith was totally committed to government and corporate sales and was no longer interested in computer kits. After losing Desktop 3, ZDS found themselves struggling in the government sales and in the commercial marketplace. By this time Heathkit was out of the kit business. ZDS continued with some clones for a while but they had become a "me too" computer supplier with little to distinguish them from the competition.

As for the old Heathkits, the old test instruments can command high prices on eBay. An unassembled capacitor tester (IT-28) recently went for $261.99 plus shipping.

on Jan 8, 2014

I always wanted the H11 but it was out of the reach of my college days finances. I had to settle for a KIM-1 and a Southwest Technical Products 6800/6809 system prior to the PC finally coming out.

I have built a number Heathkits and Knight Kits over the years and I enjoyed building and using them. There are still kits out there for anyone who really desires to build one. Elecraft makes a number of kit products for Amateur Radio. Other companies build audio products in kit form also.

In my opinion the "build it yourself" culture has replaced traditional kit building. Just go visit Adafruit, SparkFun, and the others and the module offerings are amazing. With the Arduino, Raspberry Pi and the other open platform designs, combined with shields and other modules, it is possible to design something and build it without a lot of effort. Even Radio Shack sells this stuff.

Heathkit may be gone but the spirit is still there.

on Jan 8, 2014

I have built a dozens of Heathkits throughout the years - my first was the Electronic Organ back in the late 1960's. When I first started my part-time business in the late 70's the majority of my test equipment was from Heathkits - CRT Tester/Rejuvinator - Tube Tester - O'scope - TV pattern generator - O'scope - and RF probes. (part-time business supported my Ham Radio Hobby). I also the SB-300 series and SB-230 (just sold a few years ago). I still have an SA-2060 and actively use it. There is a Hero-1 sitting in the shack that needs new batteries - but still works when connected to the charger. On my "to do" shelf is a complete unassembled Heathkit Phone patch unit.

I also took the Heathkit digital electronics courses and learned a lot from them as my formal training was in analog and RF.

When Heathkit went out of business - it was a sad day.

Sadly - many of the Amateur Radio operators today are nothing but appliance operators.

on Jan 8, 2014

Wow, what a trip down memory lane. I still have my old H89 and dual floppy drive expansion gathering dust in my garage. It might even still work, though it hasn't been powered on in years. I think I scrapped the old Heathkit dot matrix printer years ago, though. That thing must've contained 30 pounds of metal.

In retrospect, in absolute dollars that's probably the most expensive (and least powerful) computer I've ever purchased with my own money. But I was in college then and the learning I got from it was worth far more than the cost. Years later (graduate school) someone even gave me the bound HDOS source code listings! Fascinating stuff...

on Jan 9, 2014

I worked at the Byte Shop of Pasadena in those early years. I agree with him regarding Steve Jobs. He was obnoxious. I did not find Bill Gates particularly arrogant, but definitely was joylessly 'all business'. I am surprised that Gary Kildall turned them down, but then there are stories out there about him missing big opportunities. Yes, the LSI-11 was a fantastic deal at the time. I heard that even DEC was not that enthralled to see them rolling off Heath's production line. Just not what they envisioned for the product.

on Jan 10, 2014

Wow! Indeed what a trip down memory lane. Thank you so much for this historical account, and I thank all for their comments. I started my technical career as a camera repair technician right out of high school back in 1976. Back then the most advanced electronic component in a camera was the moving coil meter operated by a photocell. My boss told me electronics would be the next big thing in cameras and he told me I could get a raise if I learned about electronics. I was on my own back then and I did not earn much money. I could not afford to go to school. Instead I started to read magazines like Popular Electronics, and Radio Electronics. Each month they featured some small project one could build from locally purchased parts, which is what I did to learn electronics. At that time the market for kit computers was hot. Through the ads in those magazines I discovered the computer kits from Heathkit. I had wanted buy one but it was too expensive for me.

To get going I had built myself a massive breadboard box with a built in 5 Volt and +-15VDC power supply. I used snippets of 22 gauge wire to connect everything together. I saved my pennies and was able to buy myself a B&K Precision 5MHZ Oscilloscope, which helped me to see how the electricity was moving through my bread boarded circuits. Back then Radio Shack had a good selection of parts; also Canal Street in New York City was a gold mine of parts and subassemblies for electronics experimenters. I used to spend my weekends there browsing through the piles of scrap equipment for parts for my projects. My best friend that worked as an electronics engineer at a video company, and he helped me a lot with my electronics learning. Cameras did become very advanced electronically with fully automated exposure systems, electromagnetic shutters, and diaphragm control systems, also motor driven film advance too. As I learned more I earned more.

When Radio Shack came out with the TRS 80 my best friend and I each bought one and within days we had our machines apart, and were adding the lower case modification to the type font, more ram, etc. It was a lot of fun for me; all of this learning and then doing, to watch it all work. I enjoyed electronics so much I eventually settled on the career of industrial electrician where I design and build all new control systems for industrial machines that are based on a PLC being fed data from a wide variety of sensor types, and then outputting the results to motor drives, servos, or linear actuators to put out a manufactured product. It’s like a high tech erector set. Even though I went on to graduate 47 vocational schools, and I now have 4 college degrees, the core pieces of knowledge I use on the job everyday come from my time in the early 1970s when I was building electronic projects on my breadboard. My early days in electronics were cherished times for me and your article helped to fondly recollect those days once again. Thank you.

on Jan 10, 2014

I don't understand some of the readers negativity to Heath Kit. I built dozens of them and they all worked perfectly and some are still in daily use - such as my vacuum tube Hi-voltage tube power supply(with A, B, and C voltages easily adjusted), my component analyzer with video display (nothing finds a bad part in circuit faster!), my decade boxes, and even my mono Heath Kit Hi Fi which I still use as a reference for every record I produce or engineer. I use the test gear primarily for the repair of tube guitar amps (still the greatest sounding and selling amps). I have over 400 tube guitar amps in my collection and they are regularly tuned up or repaired to keep them at their best - for use with the musicians that I record. There has NEVER been anyone else that has toped Heath Kit for the diagnostic tools used for tube amp service. I use the Heath Kit mono tube Hi Fi pre amp and tube amp as reference for the commoners home playback system for the more than 100 million record sales that I am responsible for producing and or engineering including more than 50 gold & platinum albums. Many of my peers of my era also use Heath Products in their arsenal. I, of course also have a million dollars invested in the best modern studio gear, but I still depend on the 'built it myself' HeathKit tools on a regular basis.

on Jan 15, 2014

I was building heath kits before I graduated from high school and even in college as a EE in RF I was still building them until they closed shop.

I still have a working ET-3400 which I found at a ham swapmeet in Flagstaff Arizona circa 1990. I used this for a couple of years as a simple controller for a VHF to HF remote base system and I still power it up from time to time to check out my 68XX assembler knowledge. I'm a RF engineer but still love playing around with the old 68XX and the 3400 from time to time.

I also have the entire line of heath VSWR/power meters, an old VTVM and a 10 watt VHF power amp from 1975 and everything still works as well as when I built them.

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Lou Frenzel

Lou Frenzel writes articles and blogs on the wireless, communications and networking sectors for Electronic Design. Formerly, Lou was professor and department head at Austin Community College...
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