I thawed out line, and changed the filter. The unit still "growled" and water stream was pitiful.
I then ordered the part from you based on your excellent video
N.B. Following placing the order, the problem went away!!!
It has been 6 days and things are still OK, but I do know that in a few weeks the problem will return and I'll have to install the part. At least now I am "armed and ready" with the part. Thanks.