Calibration SwitchesSHOCK HAZARD Only qualified, service-trained personnel who are aware of thehazards involved should remove instrument covers. Always disconnect the powercable and any external circuits before removing the instrument cover. Some circuitsare active and have power for a short time even when the power switch is turned off.Two switches control the access to calibration commands. The switches are on the interface boardand are accessible by removing the top cover.Accessing the Calibration Switch1. Remove the instrument cover as described under Disassembly.2. The calibration switch is on the interface board at the rear corner of the unit. To change the cal-ibration switch settings, use a small screwdriver to move the switches. As shipped, all switchesare set toward the ON position (see below).3. Replace the top cover when finished.Do not use a pencil to move the switches. Any graphite dust that gets on theswitches will conduct electricity.Switch FunctionsSwitches 1 and 2 set the calibration configuration as follows. Switches 3 and 4 are not used.Switch 1 Switch 2 DescriptionNormal ON ON This is the as-shipped switch setting. The calibration functions are accessible after enter-ing a numeric password. The default password is 0 (zero).Clear Password OFF ON The admin/calibration password is reset to 0 when the instrument is first powered on. Usethis setting if you have forgotten the password.Inhibit Calibration ON OFF All calibration commands are disabled. This is useful where access is guarded by instru-ment seals.Keysight RP7900 Series Operating and Service Guide 2937 Service and Maintenance
