Heathkit C-3 Condenser (Capacitor) Checker: History, Restoration, Demonstration, Theory

In this video, I describe a piece of vintage electronic test equipment, the Heathkit C-3 'Condenser' checker, which is really a capacitor/resistor 'value finder' plus a capacitor leakage tester, dating from 1952.
I talk about the history of this 'checker' in the context of all of Heathkit's other capacitor checker/testers, I describe the process of restoring it to full functionality. I demonstrate its operation in all modes and ranges. Then I give a brief tour of the Heathkit manual, and end with a review of the schematic diagram and a detailed description of the theory of circuit operation.
Here is a timeline table of contents:
00:00 History
03:35 Restoration
21:03 Demonstration
33:54 Final interior view
34:09 Beauty shot
40:15 Schematic and theory of operation
I have redrawn the original C-3 schematic in CAD, and added theory of operation, operating instructions, calibration details and other information. the resulting PDF file may be downloaded here: www.serpentwebs...