APP was able to find, even in light of no model number available, a replacement part which was regrettably no longer available from the manufacturer, nor from a 3rd party supplier. APP provided me with a schematic to help in this solution, and were very diligent in making sure that I could order a part which may or may not work given the issue. To my relief, the part has worked well.
I find the APP team to be most friendly and helpful far beyond what I might normally expect. Appreciate this very useful service indeed.