After upgrade to new CPU or Processor, EXPLORE is no longer logging information to the flashback or archive files. Explore uses a CPU specific evsecin.0nnnnnn member. This means that when explore started on the new system it was using the default values which have LOGxxx set to NO.
Check the values for LOGFBK and LOGARC in the CONFIG. These should be set to yes.
Enter the CONFIG main menu and change the setting to yes and recycle the EXPLORE for VSE master region.
When EXPLORE is shut down it will create a new evsecin.onnnnnnn member.
When explore starts it will use these a CPU specific settings.