FeedbackLoop | #40 - EDC 520A DC calibrator repair and adjustment @feedback-loop | Uploaded 8 years ago | Updated 22 hours ago
This unit had a blown output stage. After repairing the output amplifier it became apparent that the unit is way out of spec. The adjustment procedure was done, which seemed to bring the instrument back to proper operation.

Manual with schematics: http://exodus.poly.edu/~kurt/manuals/manuals/Other/EDC%20521%20Operator.pdf

Discussion: http://www.eevblog.com/forum/metrology/edc-520a-repair/