The KPA may not react or boot in some rare cases. Here is a summary of my findings to get him back to life.

• Switch the main knob to off
• wait a few seconds
• switch on again

If the above did not help:

• Switch the main knob to off
• wait a few seconds
• unplug the KPA
• wait 15 minutes
• plug
• switch on again

There are different reasons why the KPA may not start anymore.
The most common thing is a corrupt rig e.g. after downloading a corrupt file

To reset the last used (corrupt) rig do like this:

• Switch the main knob to off
• wait a few seconds
• hold the 'Rig' key
• while still holding the 'Rig' key - switch KPA to tuner

If the above did not help:
There are other keys to reset other parts of the KPA memory.
To reset the (corrupt) Midi settings do like this:

• Switch the main knob to off
• wait a few seconds
• hold the 'Quick' key
• while still holding the 'Quick' key - switch KPA to tuner

To reset the (corrupt) System settings do like this:
(Note: All your system settings will be erased - but not your rigs)

• Switch the main knob to off
• wait a few seconds
• hold the 'System' key
• while still holding the 'System' key - switch KPA to tuner

If the three options above did not help your KPA back to live, you may have a completly corrupted rig library or even the firmware may be corruped
Check the sections below to recover from this.

• Switch the main knob to off
• Download the latest KPA firmware
• Get an empty fat32 formated USB stick
• Copy the unziped firmware file 'kaos.bin' to the root folder of the USB stick
• Plug the USB stick into the KPA
• Press and hold both '<' and '>' keys
• while still holding both keys - switch KPA to tuner
• Something like 'boooting and installing' will be displayed
• Wait until the firmware is reinstalled

Note: ALL the rigs will be erased during this procedure!!

• 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)
• Resinstall your rigs - I recommend to just install the stock rigs - in case you have corruped rigs on your USB stick
• Load additional rigs - check if all rigs work
• Check all the KPA settings

Note: Make a backup of your rigs before you do all this.

• 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 'Test'
• A lot can be tested (buttons, knobs, led, memory, ...)