Using the Power button
If you cannot use option 3 (Power off the system immediately) or option 4 (Power off the system immediately and then power on) on the Power On and Off Tasks (POWER) menu to stop the system, you can turn off the system using the Power button when the mode is set to Manual.
Note: Using the Power button to turn off the system might
cause results that cannot be predicted in your data files, and the
next initial program load (IPL) will take longer to complete. Using
the Power button to turn off the system will turn off all logical
partitions.
Make sure that there are no tapes in the tape units, and that the mode is set to Manual.
Do not turn the modem on or off when the system is turned off and is made ready for remote IPL. Otherwise, the system might start unexpectedly, although it turns itself off in a few minutes.
To turn off the system using the Power button, follow these steps: