TM-6PRO: Why aren't the control knobs adjusting the parameters? (Sound Modify Lock)

The TM-6PRO has a Sound Modify Lock feature that locks the functionality of the VOLUME, PITCH, and DECAY knobs to prevent parameters from being changed accidentally. If turning either of the 3 knobs produces a '"Lock" message in the display, this means the Sound Modify Lock has been enabled. Here's how to disable it: 

1. Press MENU. 
2. Cursor to highlight "SYS," and then press ENTER. 
3. Use the cursor up/down buttons to highlight "Options," and then press ENTER.
4. Cursor to "SOUND MODIFY Lock." 
5. Press the ( - ) button to choose "OFF." 
6. Press EXIT when you're finished. The new setting is saved automatically.