I have a Beosound 4000 that outputs to Beolab 2, which is then daisy chained out to a pair of Beolab 6000. One day when I turned on the Beosound 4000, the Beolab 2 led indicator remained red and did not turn green as usual (I did notice that the led flickered to green for a quick moment but reverted back to red) and no sound out of the 6000s either. I rewired the output cable from 4000 to 6000 directly, and there was sound, so the Beolab 2 is no longer receiving any signal. I tried different cables but this did not help either. Any advice on what I can do or how I can test for issues? I do have another spare Beolab 2 that doesn't fully work (but I believe various components within may still work), which I can use for donor parts, but would be great if I can get some advice on which parts or how I should go about for testing. Thanks!