Hi,
Tim wrote:

My best guess, based on your feedback and some additional web surfing,
is that it may be a Model # 83YX142 or 83YX143. But I'm unable to find
any pictures or literature to confirm this assumption.

The 142 was portable; the 143 was a counter-top model without a
lid. They were renamed to "600" in the 1960 catalog. This 142/143
first appeared in 1955 and I expect you have an early one.

73, Alan