OK; with the help of a video on You Tube I took the front panel off, then the blower cover, and cleaned out the lint I could see, both "floating" and in the blower itself; to be over ten years old, there wasn't a great deal; now to try drying on "Cotton" and see if this has remedied the problem.
UPDATE: I've dried two loads on Cotton without a shut-off. Looks like cleaning was the answer. Thank you!