A Deep Dive Into Heathkit VTVMs, Using the IM-18 As An Example

I have been restoring vintage VTVMs (most of them being by Heathkit) over the last several years, and have gathered a fair amount of experience and knowledge about them and their workings. I decided to put most of that into this single video documentary in order to share it with others. I also include complete details on how to make a suitable battery eliminator that works well with the Heathkit lineup of VTVMs. The latter 2/3 of the video features my newly CAD drawn schematic/documentation package, and the PDF of that may be downloaded here: https://www.serpentwebsite.com/filesh... with the IM-18 link near the bottom of the page Here is a timeline table of contents for this video: 00:00 Introduction & history 05:48 Opening the typical Heathkit VTVM case 06:21 Internal overview 12:06 Restoration (things that commonly need attention or replacement) 19:09 Battery eliminator 29:58 Vacuum tubes 33:34 Test leads 35:05 Calibration 46:35 Schematic diagram & circuit theory