Service manual

15
Maintenance described herein is performed with power supplied to the instrument, and protective covers
removed. Such maintenance should be performed only by trained service personnel who are aware of the
hazards involved (for example, fire and electrical shock). Where maintenance can be performed without
power applied, the power should be removed.
Voltage Monitor Zero Calibration
a. Send string "VSET 0; ISET 0; OUT OFF".
b. Short power supply output terminals.
c. Attach the DVM from
M on the rear panel through a 1kΩ resistor to A2P3 pin 3 (V-MON1).
d. Adjust A2R22 (V-MON ZERO) to 0V ±20µV.
Common Mode Calibration
a. Send string ''VSET 0; ISET 0; OUT OFF".
b. Short power supply sense terminals ( + S to - S) at rear panel.
c. Attach the DVM from
M on the rear panel through a 1kΩ resistor to A2J3 pin 3 (V-MON).
d. Take initial reading from DVM.
e. Remove both local sensing straps from rear-panel terminal block, and connect a 1-volt external power supply with its +
lead to - S and its--lead to - Out. See Figure 2-1.
Adjust A2R21 (CV LOAD REG) to Initial Reading ±20µV.
f. Replace local sense straps after removing external power supply.
Figure 2-1. Common Mode Setup