I would still like to know if anyone has had issues in link rooms when a plasma is present in another room. I have read (elsewhere) that their emissions can be remarkably powerful and long ranging.
It's still just light, so a closed door inbetween should get rid of it.
But, the processors in these Beomasters are rather slow, and they have to simultaneously keep track of several command interfaces (IR, MCL, and at least two Datalink interfaces). If the IR receiver is badly bothered by a plasma TV, it will continuously feed spurious pulses to the processor causing it maybe to miss communications from elsewhere... but this is now just speculation, and once again should bother the other IR receiver (in the link room) at all ranges.
Getting back to my original bad cap theory, the MCL boxes receive their power from the Beomaster, and so may also suffer from an unstable power supply in the BM. The IR receivers are very sensitive to power supply noise.