Since a few days my Philips Home Cinema Set has the issue that the volume button does not react properly anymore when I want to adjust the volume. It doesn't matter what setting I use, e.g. playing a CD, listening to to TV (audio from settopbox connected to the audio-in aux connection of the HTS3568), using the digital-in optical socket for a PS/3 or watching blu-rays.

Yesterday I checked if a firmware update was available on the philips support site, which I installed using the corresponding manual. Af first this seemed to help, because audio was working properly again (for the whole evening).
Today I wanted to use the device again, but first needed to unplug the device from power, because the stand-by led wasn't lighted. I turned on the device.. but no audio. I reinstalled the firmware, now I had audio again. But after a few hours the same issue: I cannot use the volume controls to in- or decrease the volume (not on the device, nor the remote control).

Does anyone have an idea how this could be fixed? I now cannot use the device anymore...