Safety first: Unplug the coffee maker before any disassembly. Mains voltage is present inside.

Check outlet and cord: Test the wall outlet with another device. Inspect the Tristar power cord for visible damage. Replace the cord if frayed or cut.
Test power switch: If your model has a mechanical rocker switch, ensure it clicks firmly. Coffee residue can sometimes jam it; clean around the switch with a dry cloth.
Internal fuse (advanced): Remove the bottom cover and locate the small glass or ceramic fuse on the main PCB or near the cord entry. Check continuity with a multimeter. Replace only with the same type and rating.
PCB inspection: Look for burnt components or tracks on the main control PCB. If present, the board should be replaced rather than repaired at home.

Warning: If the new fuse blows immediately, there is a short circuit. Do not continue replacing fuses; seek professional service.

Coffee maker does not power on at all; no lights or display.

Possible Causes