Agilent Technologies E3646A, User Manual, Page: 196 / 211

Appendix Service Information
Calibration Reference
196
Calibration Reference
Before you calibrate the power supply, you must unsecure it by entering the correct
security code. See “Calibration Overview”, starting on page 67, for more detailed
procedures to unsecure or secure the power supply.
Agilent Technologies Calibration Services
When your power supply is due for calibration, contact your local Agilent
Technologies Service Center for a low-cost calibration. The Agilent E3646A/47A/
48A and E3649A power supplies are supported on calibration processes which allow
Agilent Technologies to provide this service at competitive prices.
Calibration Interval
Recommended calibration interval for this power supply is 1 year. This will ensure
that your power supply will remain within specification for the next calibration
interval. Agilent Technologies does not recommend extending calibration intervals
beyond 1 year for any application. This criteria for re-adjustment provides the best
long-term stability.
To Unsecure the Power Supply Without the Security Code
To unsecure the power supply without the correct security code (when you forget the
security code), follow the steps below.
See “Electrostatic Discharge (ESD)
Precautions” on page 174 before beginning this procedure.
1 Disconnect the power cord and all load connections from the power supply.
2 Remove the instrument cover. Refer to the disassembly drawing on page 178 .
3 Connect the power cord and turn on the calibration mode by holding down the
Calibrate
key as you turn on the power supply and hold down the key until you hear
a long beep. Be careful not to touch the power line connections.
4 Apply a short between the two exposed metal pads on JP3 (located near U17). The
JP3 is outlined with a circle on the Digital board component locator (
top & bottom
side ) drawing.
5 While maintaining the short, move to the security code and enter any unsecure code
in the calibration mode. The power supply is now unsecured.
6 Remove the short at JP3. (An error occurs if not removed.)
7 Turn off and reassemble the power supply.
Now you can enter a new security code. Be sure you take note of the new security code.