my smxl is also crapping out from time to time. the initial indication that something is wrong is a 'cricket' sound coming from the unit. then the display goes bonkers (a highly technical term meaning that the author is ignorant of the proper term), eventually leading to 1) unit shuts down or 2) display says that the food is ready while the unit is still heating. i replaced the pc board without doing any good (or harm). i had the microwave thing-a-ma-gigger (a highly technical term meaning ...) replaced about 2 years ago, so it was not suspect. after reading your posts it now is.
is the 'cricket' sound something you have experience with?
is the 'cricket' sound relavant?
could something just be loose (not observed when i had the unit apart to replace the pc board (yelp... i took it all apart only to discover that i was only 3 screws away from having access to the pc board))?
could the thing-a-ma-gigger be bad already?
tia.
b
b