I would check all cables and connections in the first instance.

• Check that both BL4000s are connected to the Active's single PL socket - NOT the PC socket (assuming the Active is Type 1636).  You may need to daisy-chain from one BL4000 to the other.
• If possible try new PL cables from Active to at least one of the BL4000s.
• Try an alternative cable between main room BS9000 and link room/active - preferably a Masterlink cable without RJ45 adaptors.  If this works, check the ML/RJ45 have the correct pin assignments.

Also try disconnecting the BS9000 and just using BC2 as the main room source. (Not sure what BC3 is.  Do you mean BS3?)  

Just last week I had the B&O service man (who is great btw) return my Beosound 9000 with a new laser and upgraded circuit board? He tested my components and the Beolink Active and BL4000's worked fine in isolation. My cabling Cat6 is in my walls so cannot replace. There seems to be some connection as when CD is pressed on Beo4 the BL4000 lights come on but then shut down within a couple of seconds and no sound from the CD is heard.   Sorry I meant Beosystem 3 which runs the whole shebang! When I disconnect the Beosound 9000 and play a CD on the BC2 I get no response at all in the link room. In fact none of the Beo 4 buttons have any effect on the BL4000's. Disconnecting the Beosound 9000 seems to have completely cut off the link room. The 9000 is obviously part of the chain and disconnecting it stops messages going to the Beolink Active and  speakers in link room.   This is really frustrating as it has always worked fine when BS9000 was in link room with BL4000's connected directly. Any assistance would be really appreciated. paddy2042

Before concentrating on the link room I think it would be worth to consider if the main room is working correct? The reason for this is that it is not possible to have 2 audiomasters in a Masterlink network which your starting post indicate that you are trying to have with both the BS9000 and the BC2. Asuming your speakers in the main room is conncted to the Beosystem 3 can you activate the source on both the BS9000 and the BC2 and hear them in the speakers?    

Hi Madskp Yes everything in the main room is working DVD on BC2 plays the disc inserted either DVD or CD. Cd on Beo4 plays the Bs9000, and DTV plays the television so all seems okay in the main room.   When serviceman was here he connected the RJ45 to Masterlink to Beolink active in the link room and it seems to work fine. I asked him to use this cable in the main room to connect the Bs9000 as I only had one of these cables. Since I have bought a second RJ45 to ML cable and connected it to link room but this time it does not seem to work. I have tried looking at option and I believe opt 6 is the way to go with the Masterlink Active but I cannot get any sound from the Link room. I do remember once previously that the two masters did cause a problem but the technician solved this. Is it the case that now I have three masters: BC2, BS3 and Bs9000 in the same room? I wonder if there is some conflict here. I really appreciate your suggestions and will keep working on this problem and any further ideas would be really welcome. Paddy2042