OK, firstly, this topic was posted (and answered, albeit without the additional information provided here) under another username HERE. It would help everyone reading this website if users responded to the answers given rather than start a completely new thread under a different name.
Now, as this seems to be common property that requires maintenance, and your neighbour is unsympathetic, then you should consider taking action at Fair Trading and the CTTT to force the Owners Corp, that’s you and your neighbour to spend some money fixing the problem.
Also, as I think I said in my previous answer to this question, don’t you have a by-law about the peaceful enjoyment of your lot? Your neighbour is in no position (physically, morally or legally) to judge how noisy the equipment is in your home since they are far removed from it.
Fair Trading will demand a mediation session first. Take recordings of the noise on a smartphone or other digital device because they will have a time stamp on them. Then ask for a legally binding resolution at the mediation – otherwise you can proceed to the CTTT which will be time consuming and emotionally draining for both parties.
Or you could get really serious and ask for a noise abatement order at your District Court. The interesting thing about that is if you get one and they disobey it, it’s a criminal rather than a civil matter.
But try and talk it out first. As Churchill said, “Jaw-jaw is better than War-war.”