Recently, I’ve written several articles about the Heath Company and its legendary Heathkits. I based these articles on discussions with and materials from Chas Gilmore, who joined Heath in 1966, worked there on and off for more than two decades, and eventually became its VP of product development, marketing, and sales. The articles were also based on discussions with, and a book by Chuck Penson titled “Heathkit: A Guide to the Amateur Radio Products.” (See the references below for links to these articles.) Imagine my surprise when I discovered a book titled “Classic Heathkit Electronic Test Equipment,” written by Jeff Tranter, who published the book in 2013. Based on the feedback from my previous Heathkit articles, I immediately knew I’d need to review this book for the EEJournal audience, so I purchased a copy and contacted Tranter.

This comprehensive book covers Heath’s test equipment over the decades from the 1940s to the 1990s. Image credit: Amazon

Tranter has been building Heathkits for nearly as long as I have. He built his first kit, a PT-15 darkroom timer, with his father in 1974. When the freshly assembled darkroom timer didn’t work properly, Tranter immediately put Heath’s motto, “We won’t let you fail,” to the test. He made some electrical measurements with his Radio Shack voltmeter and then went to the Heath retail store in Mississauga, Ontario where a service technician diagnosed the problem as a blown SCR, based on Tranter’s measurements. He gave Tranter a free replacement SCR. Tranter took the new SCR home and soldered it in place of the original, which brought the darkroom timer to life. Within a few years, Tranter had become an amateur radio operator (a ham) and subsequently purchased many additional Heathkits.

As he nears retirement, Tranter has become a serious collector of old Heathkits. He’s fed his collection habit from local purchases, the Internet, and eBay. The result was a growing collection of restored and working Heath products, which led to his book about Heath test equipment. I especially enjoyed the book because it includes information about several Heathkits I’ve built. The book’s eleven chapters and appendix cover multiple instrument categories including component testers and substitution boxes, frequency counters, analog and digital meters, oscilloscopes, power supplies, signal generators, tube testers and checkers, and miscellaneous other Heath products.

The book also includes an amusing homage to the ingenious Heath nut starter, which was little more than a cheap, molded polyethylene tube that held a 3-48, 4-40, or 6-32 nut in position in tight, hard-to-access places while you tightened the associated screw. Heath originally shipped one of these nut starters in every Heathkit and charged a mere 15 cents for a replacement. I kept one of these tools in my toolbox for many years, and I wish I still had it, not to use it, but for nostalgic reasons. You can still find the original red plastic nut starters from Heathkits on eBay or you can buy new ones molded in black plastic from Small Bear Electronics for $4.99 or from the descendent of the California company that supplied them to Heath, now branded as Menda, for $2.45.

Small Bear Electronics sells this replica of the Heath nut starter for $4.99. Menda sells one for $2.45. Image credit: Small Bear Electronics

The instruments described in the book that I have a personal connection with include the IM-18 vacuum tube voltmeter (VTVM). As a senior in high school, I convinced my AP physics teacher to purchase one of these kits so that the class could assemble it as a group project. We were caught red handed when the school principal discovered us working on the kit in the classroom instead of attending a pep rally. One new thing I learned from Tranter’s book is that Heath produced two plug-in modules for the IM-18 VTVM that replaced the 6AL5 and 12AU7 vacuum tubes with transistors. As a result, there was no longer a warm-up needed, and the instrument was ready to take measurements as soon as you switched it on.

This Heathkit IM-18 VTVM resembles the one my high school AP physics class built in 1971. Image credit: Radiola Guy

Tranter’s chapter on meters does not mention my beloved IM-25, a solid-state VOM (volt-ohm meter), or FET VOM as I called it. This 6-inch analog bench meter had an FET front end instead of using a vacuum tube for signal amplification. As I recall, it drifted a lot and there was a large thumbwheel on the right side of the instrument that always needed to be re-zeroed whenever you turned the unit on. The IM-25 also had an internal battery holder so you could take measurements without a power outlet, although I never did that. This meter does appear in the book’s appendix and is listed simply as a VOM. Analog FET VOMs like the Heath IM-25 were soon replaced by DMMs (digital multimeters) and therefore had a very short-lived existence during the transition from the VTVM era to the era of DMMs.

The Heathkit IM-25 FET VOM replaced VTVMs for a short period in the 1970s, but they were soon supplanted by DMMs. This meter exhibits the beige paint mange that’s typical of old Heath instruments from this era. Image credit: Recycled Goods

The chapter describing Heath’s frequency counters mentions the IM-2420, a digital frequency counter from the LED era. The IM-2420 employs a temperature-controlled, 10MHz crystal as a frequency reference. That was a fairly advanced technology for a kit back in those days. The crystal and heater in the IM-2420 are housed in a custom-molded Styrofoam box to maintain the elevated temperature created by the heater. Heath got into the frequency counter business early by developing several instruments based on Nixie tube displays before switching to LEDs. I’ve got an SM-2420, a factory-built version of the IM-2420, that I purchased from eBay a year or two ago. It appears to have been stored in a barn for several decades because the metal on the circuit board is badly corroded and even the metal shafts on the rotary switches are pitted with corrosion. It’s going to be a very challenging restoration project.

The chapter on power supplies includes an in-depth analysis of Heath’s IP-27 low-voltage power supply, which Heath billed as “the finest low voltage supply Heath has ever offered.” I remember building one of these power supplies in high school, and it was indeed a rugged unit, capable of supplying as much as 50Vdc at 1.5A. The IP-27 was a linear power supply, and it relied on multiple taps on the transformer’s secondary winding to keep power and thermal dissipation low in the output pass transistors. The only thing that failed on my copy of this power supply was a banana jack/binding post, so I replaced all three of the relatively wimpy aluminum Heathkit jacks with beefy commercial binding posts. As I recall, some drilling of the front panel was required to accommodate the larger posts. (I still have a thing for quality binding posts.)

The Heath IP-27 linear power supply was a real workhorse. This supply, from Heath’s beige era, still has its original binding posts. Image credit: Jeff Tranter

Another instrument of interest that was missing from the book’s chapters was a discussion of the IG-18 sine-square wave generator. I remember building this audio-frequency signal generator kit in the early 1970s and marveling at the ingenious use of a tungsten lamp’s negative thermal resistance to stabilize the generator’s oscillator output, as explained in the manual’s circuit description. What I didn’t realize back then was that the design was based on Bill Hewlett’s Master’s thesis, which resulted in the Hewlett-Packard Company’s first product: the Model 200A audio oscillator.

Tranter’s book is a lovely waltz down memory lane for legions of Heathkit builders like me. One fact that jumped out of the book at me is the mention of US Arizona Senator Barry (In Your Heart You Know He’s Right) Goldwater, another ham, who built more than 100 Heathkits and who flew his private plane, a Beechcraft Twin Bonanza, from Arizona to Heath’s headquarters in St. Joseph, Michigan to purchase additional kits. Such is the commitment of Heathkit aficionados.

A paragraph that appears early in Tranter’s book sums up the current state for purchasing Heathkits:

“The holy grail for some collectors is an unbuilt Heathkit still in the original box. These show up periodically on eBay, but expect to pay a king’s ransom. Beware that it may be partially built and/or have missing parts. Buying a sealed box sight unseen could be risky. If you are successful in acquiring it, the question becomes whether to assemble it or keep it (possibly as an investment). If you do assemble an original kit, I encourage you to make a video and put it on YouTube for others to appreciate. Oh, and if you have an unbuilt kit and aren’t comfortable assembling it, I would be happy to do this for you.”

He’s not kidding about the pricing of Heathkits and parts. Check out the prices on eBay. Prepare to be shocked. Tranter has continued to actively collect Heathkits since he published his book in 2013. He’s added more than 70 Heath test and ham products to his collection over the last dozen years. Taking his own advice, Tranter has posted restoration videos for many of these products on YouTube. Click here to check out his YouTube channel, which currently lists more than 200 videos about Heath products and electronic products from other vendors. Tranter has recently published another book about Heathkit products titled “Classic Heathkit Computers, Calculators, and Robots.” You might want to check out that book as well.

How about you? Did you build Heathkits? Which ones do you particularly remember? Which most affected your career path?

Read the full Heathkit history series on EEJournal:

The Rise and Fall of Heathkit – Part 1: Early Days

The Rise and Fall of Heathkit – Part 2: The 1960s through the mid-1970s

The Rise and Fall of Heathkit – Part 3: The Microcomputer Kit Era

The Rise and Fall of Heathkit – Part 4: The Demise of Heathkit

The Rise and Fall of Heathkit – Part 5: Final Thoughts

The Rise and Fall of Heathkit – Part 6: And Yet More Final Thoughts

Read all five articles in the “H is for Heathkits and Hams” series:

“H” is for Heathkits and Hams: Part 1 – Early Days through the 1950s

“H” is for Heathkits and Hams: Part 2 – The 1960s

“H” is for Heathkits and Hams: Part 3 – The 1970s

“H” is for Heathkits and Hams: Part 4 – The 1980s, 1990s, and the end

“H” is for Heathkits and Hams: Part 5 – Reasons for Heath’s Success in Amateur Radio