HP 6642A calibration

[jfgilbert]

Hello,
I am trying to calibrate an HP 6642A powers supply. The process, as detailed in the operating manual is quite straightforward and does not require exotic equipment, so I decided to try it even though the supply is not significantly off. I am able to go through the complete process easily and it tracks the instructions exactly. The only difference is that, at the end, when I press the "Cal Save" button and it is supposed to reply with something like "CAL SAVED", nothing happens and it stays on the last message "CAL COMPLETE."
Am I missing something, or is that a sign of something seriously wrong with the device?
Thank you for any ideas or suggestions,
Jacques