DIAGNOSIS Total power failure usually points to the internal fuse on the control board blowing, often from a power surge or compressor startup spike.
FIX First, try a different, known-good outlet on a different circuit. If still dead, unplug it and check that the power cord is fully seated where it enters the back of the unit—sometimes it can get partially pulled out.
IF THAT DIDN'T WORK The next step is checking the internal thermal fuse or main board fuse. This requires opening the cabinet near the power cord entry point. If you see a small, clear-glass fuse, test it with a multimeter. A blown fuse here is a common fix.
HEADS UP If the internal fuse blew, it was likely for a reason like a voltage spike. Plugging the unit into a quality surge protector (not just a power strip) is non-negotiable for longevity, especially in older homes.