If it was me I would rip out the stock power supply and replace it with a higher quality independent system made in backwoods China being if you have ever looked at any Bose equipment in detail and cross referenced their parts to anything you will find that they are usually made out the cheapest crap they can get away with. Just look at most of their commercial sound speakers that are in enclosures that don't have removable covers over the speakers. They are the cheapest looking and built paper coned stamped low grade metal framed POS components you will ever see backed up by a a ton of signal processing to make them sound sort of reasonably good in most controlled environments.
Really. Try running bose speakers on a good audio system by themselves. They suck big time without the heavy signal processing or try running some good high quality speakers off a bose system. They too will sound terrible due to the excessive amount of unnecessary signal processing that is being fed to them.
Honestly given the amount of rebuild work you have done to that power supply already to keep it functioning it's apparently built about as well as the rest of their stuff.