I spoke to my mechanic. He said he talked to Gyro House, and to paraphrase my mechanic, and I quote "..they said it's out of warranty and there's nothing we can do blah blah blah -- eff you."
Except instead of "eff you" my mechanic used an epitaph, but he may have been exaggerating.
Yes, the filters were clean (and are replaced every annual), and yes the vacuum pump is fine, and no there does not appear to be any source of contamination.
And, to paraphrase my mechanic, he said "we've had issues with other Gyro House stuff, so we don't use them much."
So, maybe I should be a good little customer and just accept the fact that my expensive AI went belly up after 18 months/80 hours and shut up and buy another one.
I will buy another one, but not from Gyro House. Your mileage may vary.
And if someone from Gyro House does not like me posting this on the internet, by all means reply here on this forum, and we can have a discussion.