Uploaded January 2025 | Updated September 2026, 1 week ago

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In this video, I describe the Heathkit IM-12 Harmonic Distortion Meter. I talk about its history, restoration, and making a new 3D printed lamp socket holder for it. I then briefly demonstrate it, show the manual, and give a walk-through of the schematic diagram while describing the circuit theory of operation.

Timeline Table of Contents
- 00:00 Introduction & History
- 05:54 Overview (internal & external)
- 19:16 Restoration
- 31:29 New 3D printed lamp socket holder
- 47:45 Test & Demonstration
- 1:00:15 Beauty shot
- 1:00:33 Overview of Heathkit's manual
- 1:10:29 Schematic & circuit theory