Test results with 1500W toaster--

Load worked well--toaster heated normally

Microwave unit functioned as in the past--it shutdown the transformer
load (toaster in this case vice magnetron and cooling fan) after a
period of time with the exception that the run cycle continued for an
additional 10 sec over actual magnetron and fan loading tests.
(Additional ten seconds may have resulted from no magnetron heating at
all.)

Suspect: 1. Faulty temperature sensor--perhaps opened thermistor or 2.
bad relay/control unit

Any thoughts Sam?