Dear community I wanted to share an update on above topic. As no spare parts are available for the BeoSound 9000 any longer, my official B&O dealer was unable to repair the device. However, I did find a gentleman in Switzerland who buys old B&O equipment and uses it to refurbish or repair "vintage" models as mine. In my case, they had to fix the sled, replace the MasterLink module and do some soldering on the amplifier. Works and looks as new! I paid EUR 330 for the repairwork. Should you be interested, you can contact Mr. Beck here: gery-beck at bluewin.ch

Thanks zuegers07 for the information on Mr Beck. I got in touch with him about my BS9000 as it needs a new laser and check up after a lot of use.