Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives Magazine Sponsor RF Cafe Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Alliance Test Equipment Centric RF Empower RF ISOTEC Reactel RF Connector Technology San Francisco Circuits Anritsu Amplifier Solutions Anatech Electronics Axiom Test Equipment Conduct RF Copper Mountain Technologies Exodus Advanced Communications Innovative Power Products KR Filters LadyBug Technologies Rigol TotalTemp Technologies Werbel Microwave Windfreak Technologies Wireless Telecom Group Withwave Sponsorship Rates RF Cafe Software Resources Vintage Magazines RF Cafe Software WhoIs entry for RF Cafe.com Thank you for visiting RF Cafe!

Windfreak Technologies Frequency Synthesizers - RF Cafe

Innovative Power Products Passive RF Products - RF Cafe
Anatech Electronics RF Microwave Filters - RF Cafe

Vintage Heathkit IM-104 Solid-State Voltmeter
Cool Product Report

Featured Product Archive

The inventions and products featured on these pages were chosen either for their uniqueness in the RF engineering realm, or are simply awesome (or ridiculous) enough to warrant an appearance.

| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 |

<Previous                     Next>


IM-104 Solid-State Voltmeter in the Spring 1976 Heathkit catalog - RF Cafe

Vintage Heathkit IM-104 Solid-State Voltmeter in the Spring 1976 Heathkit catalog.

This vintage Heathkit IM−104 Solid-State Voltmeter kit showed up on eBay. Although I only own a couple Heathkit items, I have been saving the images of many unbuilt kits in order to preserve the history. They regularly appear and disappear on eBay all the time - some models more than others.

One of the earliest instances of the IM−104 Solid-State Voltmeter being offered for sale was in the Spring 1976 Heathkit catalog (p54), at a cost of $94.95 ($504.55 in 2023 money per the BLS) in kit format, or $149.00 full built and tested. That was/is a lot of cash to lay down for a multimeter that measures AC/DC voltage and current, and resistance. However, the alternative if you needed a high input impedance instrument, this was still cheaper than buying a vacuum tube voltmeter (VTVM), and it is much smaller, lighter weight, and portable due to being powered by batteries (a D cell and four AA cells). An article like "The Case for the Transistorized Multimeter" was evidently deemed necessary in the 1968 issue of Popular Electronics magazine to convince the VTVM faithful that the newfangled DMM would make their lives better.

From the Spring 1976 Heathkit Catalog:

Heathkit FET taut-band VOM - ten megohm input in a portable meter.

A portable lab-grade FET VOM combining accuracy, versatility, convenience and ruggedness - in an easy-to-build dollar-saving kit! Our IM-104 has low-drift 1% precision metal film and wirewound resistors for exceptional stability. Nine DCV & ACV ranges measure from 0.01V to 1000V. Six current ranges cover 0.001 mA to 1000mA, DC & AC. Seven resistance ranges from 1 ohm to 100 megohms, conventional or low voltage modes. Decibel ranges from -40 dB to +62 dB. DC null scale with better than 1 mV resolution. The 4 1/2" ruggedized, taut-band meter is diode protected, built to take plenty of abuse. Built-in circuitry shows battery condition at the flip of the range selector. Three evenings put this great portable VOM on your bench.

Kit IM-104, Shpg. wt. 4 lbs. 94.95

Assembled SM-666, has additional 1μA current range, less 100 & 1000 mA ranges, Shpg. wt. 4 lbs. 149.00


DC VOLTMETER - 9 ranges: 0.1, 0.3, 1, 3, 10, 30, 100, 300, 1000V. Input resistance: 10 megohm. Accuracy: ±2% of full scale (meter in horizontal position). AC rejection: Accuracy not affected by impressed 60 Hz sine wave with rms 2x greater than full-scale value.

Heathkit IM-104 Solid-State Voltmeter (front panel) - RF Cafe

 Heathkit IM-104 Solid-State Voltmeter
(eBay photo) 

Heathkit IM-104 Solid-State Voltmeter Shipping Carton Contents - RF Cafe

Heathkit IM-104 Solid-State Voltmeter Shipping Carton Contents
(eBay photo)

Heathkit HW−5400 HF SSB Transceiver Schematic - RF Cafe

Heathkit HW−5400 HF SSB Transceiver Schematic (c1985)

Heathkit Spring 1978 Catalog - RF Cafe

Heathkit Spring 1976 Catalog Cover

Heathkit IM-104 Solid-State Voltmeter (rearl) - RF Cafe

Heathkit IM-104 Solid-State Voltmeter - back
(eBay photo) 

Heathkit IM-104 Solid-State Voltmeter Instruction Manual - RF Cafe

Heathkit IM-104 Solid-State Voltmeter Instruction Manual

Heathkit products were well known for the completeness of its instruction manuals, with clearly illustrated instructions. During the writing and editing process, Heathkit employees were given pre-production kits to take home and build, while annotating any difficulties or errors encountered. Doing so helped minimize the situation where the writer inadvertently assumes his own familiarity with the process is shared by the customer. Having built a few Heathkit products myself in the 1970s when I did not have a lot of experience with electronics assembly, I can attest to the user friendliness of the instructions. Heathkit still sells many of its vintage manuals for around $15, which is what you would pay on eBay.


Contact Info

Heath Company (Heathkit)
Operations: PO Box 15, Ottsville, PA 18942
R&D/Mfg: PO Box 3115, Santa Cruz CA 95063
Phone: +1 (831) 480-4368
E-Mail: info.2015@2015.heath.company



Posted November 29, 2023

TotalTemp Technologies (Thermal Platforms) - RF Cafe

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

1996 - 2024


Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

Copyright  1996 - 2026

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website: AirplanesAndRockets.com | My Daughter's Website: EquineKingdom

KR Electronics (RF Filters) - RF Cafe

LadyBug RF Power Sensors

withwave microwave devices - RF Cafe