I googled the 'symptoms' and found it was a common problem, and the fan needed replacement.
I ordered the fan and it was easy enough to install, took about half an hour. Unfortunately, the unit refused to work at all after that, and had to call a repairman, who said the PLUG had gone bad.
The unit had been running prior to the installation of the new fan, but not after. So, I got a replacement plug from the big box store, cut off the old one and replaced it. The new fan works and the new plug works, and the 'fridge is good to go! The repairman said he had only seen this
(the plug going bad) happen twice in 30 years. The fan was not difficult to replace, nor was the plug.