Tristar Control Logic / Relay Drive Failure

Timer counts down but heater and fan both remain off; only display is active.

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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

Failed heater and fan relays on PCB, Corrupted firmware on main control PCB, Broken control traces or cold solder joints

How to Fix / Troubleshooting

Safety: Unplug before inspection.

  • Reset: Perform a full power reset by unplugging for 10–15 minutes.
  • Check door/basket switch:
    • If the switch is not detected as closed, the board may inhibit heater and fan; test and replace the microswitch if faulty.
  • Inspect PCB (advanced):
    • Open the housing and examine the main control PCB.
    • Look for cracked solder joints around the relays or triacs controlling the heater and fan.
    • Resolder any visibly cracked joints if you are experienced with electronics.
  • Replace PCB: If relays are not energizing despite correct inputs, replace the main control PCB.
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Repair Difficulty

Hard 4/5

Required Part

Main Control PCB
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