Ash, thanks for your suggestions. The projector is under warranty and I am leaning in the direction of getting another replacement, if possible. If not, then it'll have to go in for repair.
Regarding air versus vacuum. There doesn't seem to be a concensus on a best way to clean the internal parts of a projector. Whatever works, I guess. However, it appears, from your description, to be a significant effort requiring hands-on skill.
In the end, I strongly feel new or would-be owners of projectors must be made aware of potential (or eventual) difficulties up front. They should know 1. what manufacturers claim is NOT necessarily true; 2. a projector MUST be inspected and tested upon receipt while knowing WHAT to look for and HOW to look for it; And 3. that modern digital projectors are VERY complicated and sensitive, requiring extra care, more so than any electronic device thay have or will ever own.
There's no doubt, a knowledgable projector owner (with money and time to spare) is a happy one. Right now, unfortunately, I am not one of those. I'll reluctantly give it one more try.