After searching for information, the best guess was a defrost problem, so I first fully defrosted and reset the ice maker (this is the recommendation of Samsung and others on the net). This did not fix the problem.
Next best guess was water fill valve, but after removing ice maker from fridge, determined it had cubes in it but would not eject.
So, finally decided to order replacement ice maker. If you search the next for this model (DA97-13178A) there are instructions for removal of the ice maker. Removal is only 2 screws and disconnecting 1 cable harness, so not too bad at all. Replacement ice maker fixed the problem!