F5
LG Studio Relay Drive or Control Board Failure

Oven displays F5 and may not start or may shut down mid-cycle.

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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 relay on main PCB, damaged relay driver circuit, overheated control board, loose power connections to PCB

How to Fix / Troubleshooting

Safety first: Disconnect power at the breaker before removing any panels.

  • Power reset: Turn the breaker OFF for 5 minutes, then ON. If F5 reappears immediately, proceed with inspection.
  • Access main PCB: Remove the rear upper cover to expose the control board. Look for burned spots, cracked solder joints, or melted connectors near the relays.
  • Check terminal tightness: Ensure all screw terminals and plug connectors on the PCB are tight and fully seated.
  • Smell test: A burnt odor near the board often indicates a failed relay or component; in this case, the board should be replaced rather than repaired in the field.
  • If no visible damage but error persists: The main PCB is likely internally faulty and should be replaced with the correct LG Studio part number.

Note: Component-level repair of the PCB is not recommended for most homeowners; replacing the entire board is safer.

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Repair Difficulty

Hard 4/5

Required Part

Main Control Board (PCB)
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