The 1989 Sub Zero 511 is soldiering on after a new evaporator in 2012 and a condenser fan in 2013... The next challenge...
I was hearing a loud rattle from the freezer - sounded like the fan blade was loose.... When I crawled in the freezer and took the cover off, the freezer evaporator is iced up to the point where the freezer fan is hitting the ice.
Freezer compressor was running - very warm to the touch.
I left it off overnight, let everything thaw, (threw all of the food away...) and restarted the freeezer on Saturday AM. So far, so good, but I am not so foolish as to think there is not an issue somewhere.
So - what do I have here? A defrost issue? Sealed system issue? Cold control? Defrost timer/heater?
Thanks, all - this appliance is becoming like family - I hope it goes off to college soon.