DURKOPP ADLER 869-M Premium Service Instructions Manual page 167

Troubleshooting
2. Hold button F pressed and at the same time switch on the machine at
 The display shows the this mask:
3. Press all the buttons on the control panel in any order except for ESC.
 If a button is functional, then the corresponding box on the display
4. Press the ESC button to end.
 If all the buttons are functional, the display shows the following status
5. Press the OK button.
If one or several buttons are not functional:
 The display shows the status message
Service Instructions 869-M PREMIUM - 00.0 - 07/2018
the main switch.
will be filled in (highlighted brightly).
If the button is not functional, then the box stays empty.
message:
The control panel has to be replaced.
...
Keys NOT OK!
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