Yes, it's the model you mentioned.
I should've posted an update this weekend.
I finally got it operating satisfactorily but I had to spend about $45 to make it happen.
I did everything I knew how to, to diagnose the problem. Checked the alignment of all the pulleys, checked and adjusted the belt tension, checked the installation of the chuck, etc. etc.
I went back and talked to the people at Woodcraft, and the only additional thing they suggested was to check the belts themselves to see if there were any irregularities (there were none).
So with no other ideas, I bought six feet of Powertwist flex link belt.
That solved 95% of the problem. I also used a piece of scrap wood to lever the motor a little farther back than I could by hand, to put more tension on the belts. I shimmed the base a little to make sure it was absolutely level on the floor.
I tried to call Jet over the weekend, but evidently they're only there Monday through Friday. I'll have to call them back this week.
I notice that the forward pulley is not spinning perfectly true, although the other two are. Same with the spindle that pulley is on. Although, strangely, this doesn't translate to the chuck, which looks to be spinning dead-on centered. But I think this pulley is causing what remaining vibration exists. Hopefully Jet will have some suggestions and/or a send a replacement.
Anyway, it's performing acceptably now. I don't like the idea of having to have spent almost $50 to make it operate like it should have out of the box, but at least it's working.
This is the first issue I've ever had with a Jet tool (and I have their band saw, jointer, and drum sander in addition to the drill press). I still trust the brand, but they aren't exempt from problems.