Solution when cleaning not works!!

Unfortunately for me the tip has helped with the cleaning only for the volume keys.
The program, Mute and change key could not revive itself.
However, the solution is then quite simple. Check first if the board is still in order.
For this test with a metal object, whether the contact is still working.
If so, double-sided adhesive glue aluminum foil, cut to fit and connect
stick to non-functioning buttons.

And everything is like new.