Are you 100% secure that the lower panel is re-fitted properly and that the glass itself is fully secured in its plastic surround (it often comes unglued)?  The glass only needs to be slightly raised above the little rubber contacts and it will not function. Alternatively, can you operate the controls with the glass panel removed, by lightly touching the little rubber contacts that would normally press against the bottom of the glass panel? Can you fully control the BC9000 with the remote? (EDIT:  I moved your photo from the other duplicate thread, which I will now delete)

Thanks for your reply mate. The buttons aren’t working even with the glass panel removed. I am worried I damaged a wire or board when trying to prop up the cover. I don’t have the remote anymore unfortunately. Also apologies, it’s a Beocenter 9500

Remove the lower glass and check the security of the ribbon cables to the lower panel (connector P63), and the ribbon connectors to the left and right side of the panels.  Check also all those cables/cnnections that are being disturbed when rotating the Beocenter top panel into the service position. Do you have a service manual/multimeter?  If so, I would start by checking power to those lower panels for which you need to refer to service manual.  There is also a Test Mode but this is initiated by short circuiting two pins on the lower panel so it may not work, and I doubt that it would tell you much. Anything more than that and you are going beyond my knowledge, but let's hope it's just a loose connection!

Thank you so much. I will check the ribbons and the connections. All else fails, I have found a Hi-Fi service in Perth WA. Hopefully they know their way around Bang and Olufsen. Just want it to work and sound like it did when I bought it in the 90s