Troubleshooting by "usual suspects" is a valid approach, especially when the trouble is intermittent. I'd say the brushes would fall into that high probability range if you were talking about an alternator that has been in your car a while, but one out of a box from Azone would be different. Chances are that simple to rebuild part has been done.

Be sure your harmonic balancer is still in one tightly-held assembly. It may look like the alternator is turning, but if the belts are not tight, oily, or the balancer is slipping, the revolutions will be limited just as the alt's output begins to get serious.

If your battery light works with key on engine stalled, the small D+ wire is very likely OK. Since you replace the unit yourself, you likely know the ground wire is OK. Pretty hard to mess up the B+ wire, like you say, replacing an alternator in a 240 is not specially hard to get right.

Getting home 850 miles without an alternator? Now that's a real challenge day or night.
--
Art Benstein near Baltimore

Why do dogs love humans?
They don’t, they just like biscuits.