Tristar Start Circuit / User Interface Fault

Coffee maker powers on but will not start brewing when the start button is pressed.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Faulty start button on keypad, Child lock function enabled (on some digital models), Loose keypad ribbon cable, Firmware lockup on control PCB

How to Fix / Troubleshooting

Safety first: Unplug the unit before opening the housing.

  • Check for lock mode: Some Tristar digital coffee makers have a key lock feature. Refer to the manual for the unlock combination (often holding a specific button for several seconds).
  • Try a reset: Unplug the coffee maker for 5–10 minutes to reset the control board, then plug back in and test.
  • Test other buttons: If other buttons respond but START does not, the start key on the keypad may be faulty.
  • Inspect keypad cable (advanced): Remove the front/top cover and reseat the ribbon cable between the keypad and main PCB. Look for cracks in the flexible cable.

Note: If the keypad membrane is worn or cracked, the entire control panel assembly may need replacement.

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Repair Difficulty

Medium 3/5

Required Part

Control Panel / Keypad Assembly
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