I did the reset below and I still have crackling.
- Switch the main knob to off
- Hold the left/top soft-key above the LCD
- while still holding this key - switch KPA to tuner
- Maintenance Module will be started
- In the 'Maintenance' menu goto 'Memory'
- Use Memory FormatFlash and InitFlash
- Check if the KPA works (booting, tuner)
- Check all the KPA settings