EEVblog #210 - Krohn-Hite DC Voltage Standard Teardown & Calibration

A Krohn-Hite MV106J DC Voltage Standard calibrator landed on Dave's bench. What's inside? How does it work? Is it still within spec?, and what's all this (lack of) Kelvin-Varley and LM299 zener reference stuff anyhow?
And no adventure in calibration check is complete without a visit to the TrioSmartCal lab.

Service Manual with schematic: http://www.eevblog.com/files/MV106%20Service%20Manual.pdf