How can I perform adjustment on my U3401A or U3402A DMM when it is due for calibration?

An automated calibration system is used for the adjustment. and it is only available at Keysight Service Center. If adjustment is required, you may send the instrument to your local Keysight Service Center for calibration adjustment services. However, you can also carry out the performance verification test in accordance to the procedure found in the User's and Service Guide.