Hallo und Guten Morgen,
hier die Steps zum reaktivieren:

Put your AS/400 or iSeries machine into manual mode through the control panel for nonpartitioned machines. For partitioned machines, sign on to your primary partition and use the Work with System Partitions option, under the System Service Tools (STRSST) menu, to change your partition's startup mode to "Manual." IPL the system.
OS/400 will display the Use Dedicated Service Tools menu before it IPLs. Select option 5 (Work with DST Environment) from that menu.
When the DST sign-on screen comes up, sign on with the DST security capable user ID of QSECOFR. (Note: This is a DST-only ID that is maintained separately from the QSECOFR user profile.) The default DST QSECOFR user password is also QSECOFR.
Select option 6 (Service Tools Security Data) from the Work with DST Environment menu.
Select option 1 (Reset Operating System Default Password) from the menu that appears, and follow the directions to reset the QSECOFR password. After executing this option, the QSECOFR user profile password will be reset to its default value of QSECOFR for this IPL only.
Exit back to the Use Dedicated Service Tools menu, and select option 1 to IPL your system.
When the system comes up, change the QSECOFR user profile to *ENABLED (if it's currently set to *DISABLED), and be sure to change QSECOFR's password to another password that is harder to crack. The default password, QSECOFR, is well-publicized on the Internet, and it will be the first password a cracker tries as he attempts to hack your system. It's also important to change your password immediately because some IBM documentation on this technique specifies that the system default password reset may only last for this one iSeries or AS/400 IPL.
Reset your OS/400 IPL options back to normal mode.