Hello, I have a perfectly working BeoCenter 9500, however, a long time ago I noticed that the lower display started to become less bright than the upper one. The touch controls work perfectly. Tested it again yesterday, and now not a single LED is lit on the lower display. I have already changed the complete lower display for one that I know works 100%, but the display (that is, the three boards) remains black. Any idea where I should start looking? Thank you in advance