maintenance-manual · English
EAI 580/680 Scientific Computing System Maintenance Series: Digital Voltmeter — Chapters 4–5 (Maintenance and Calibration)
Chapters 4 and 5 of the EAI 580/680 Maintenance Series manual for the Model 28.268 Digital Voltmeter (DVM). Chapter 4 covers maintenance procedures including test connector pinout, reference circuit and power supply checks, input amplifier balance verification, resistor matrix and comparator checkout, digitizing circuit troubleshooting, accuracy checks with tabulated input/readout tolerances, and display unit lamp replacement and lens adjustment. Chapter 5 provides the full calibration procedure, specifying required test equipment (precision voltage divider, galvanometer, stable DC source), reference level adjustment using the 6.750 Reference Amplifier, full-scale adjustment, and summing resistor trim pot procedures for the ±100 V, ±10 V, ±1 V, and ±0.1 V ranges.