Summary: Dave does some performance checks and then tears down a Krohn Hite EDC 4601 0.05% 6 decade 1ppm resolution 0-1000V AC voltage standard. Service Manual with schematics MV106 DC Voltage Standard User manual Datasheets: Vactrol XR2228 Multiplier/Decoder Epson SPG8640 oscillator/divider Forum HERE Hires teardown photos:
