DIAGNOSIS The warming plate heating element has likely failed. This is a known point of failure on this model.
FIX Unplug the brewer. The warming plate is not user-serviceable. You must replace the entire base assembly, part # SP-2A. It includes the warming plate and its wiring. You will need a Phillips screwdriver to remove the bottom plate of the brewer and disconnect the old wiring harness.
IF THAT DIDN'T WORK Check the thermal fuse on the warming plate circuit. If the element shorted, it may have blown this fuse. It's a small, glass-encased component soldered to the board. Testing requires a multimeter. If blown, the entire main control board likely needs replacement.
HEADS UP Never operate the brewer without the carafe in place on the warming plate. The thermal cutoff can fail prematurely if the plate overheats. This is a safety feature.