Well, it didn't work with the BM5500, which might have something to do with that particular Beomaster not working with MCL in general.
I connected the wires to a Speakerlink connector on my BS6500, and the display lit up
Funny that the user manual doesn't give a clear answer on the on/off behaviour of the display. I guess it would light up even in line mode if it needed to display the overload message.
@Mico: sorry
As you might have guessed from a vague listing with a bad picture, they are nothing like mint. Not bad though, but one of them has been rubbed against something so the plastic cover will need polishing and there are a number of small scratches on the metal. One of the plastic parts on the top edge is missing, and I'll need to fabricate a replacement if these end up lower than eye level. They look fine from a couple of meters though, so I guess the price was OK especially now that they seem to be working... Never seen a pair for sale over here so I had to have them 