That is the way it works.
Pad events are only sent into the sequencer when the active track is set to DRUM, not when set to MIDI.
It needs to have external MIDI coming into the MPC, for MIDI events to be sent into sequencer when the active track is set to MIDI.
MPC3000 Operator's Manual, Page 35-36 wrote:The Track Data area (lines 4-6):
• The Type field:
This is a choice field with two options—MIDI and DRUM:
1. MIDI: Select this option if you want to record normal non-drum MIDI data from an external MIDI keyboard into the selected track. MIDI tracks do not use the internal sound generator or pads.
2. DRUM: Select this option if you want to record drum data into the selected track. Drum tracks are the same as MIDI tracks except for the following:
A. The output of the track plays to the internal drum sound generator.
B. You can record drum notes into the track using the front panel pads.
C. In sequence editing screens, note events in drum tracks are visually identified and selected not by note number only as in MIDI tracks, but also by the pad number and sound name currently assigned to the displayed note number.
D. Drum tracks are not affected by the Transpose function.