Whirlpool Microwave Inverter Board W11578579, Replaces W11504539

W11578579 is a genuine Whirlpool microwave inverter power board used on select JennAir, KitchenAid, Maytag and Whirlpool built-in microwaves and microwave/oven combinations. It replaces discontinued Whirlpool part number W11504539 when fitment is confirmed by the appliance model number. The inverter regulates high-frequency power supplied to the magnetron during microwave cooking.

Important: A completely dead microwave is not automatically evidence of inverter failure. No-power and no-heat symptoms may also result from the magnetron, line fuse, thermal protector, door-interlock switches, noise filter, wiring, power-supply board or main electronic control. Confirm the inverter board is defective before ordering.

Is This the Right Part?

Confirm the complete model number and revision before ordering. Similar-looking inverter boards are not automatically interchangeable — connector positions, mounting points and power ratings may differ.

Common Symptoms

• Microwave runs without heating — turntable spins, light works, but no heat produced
• Microwave shuts down during cooking
• Intermittent heating — food barely warm after a full cycle
• Inverter-related error codes displayed
• Abnormal inverter noise during operation
• Magnetron not receiving operating power

Check Before Replacing

• Test the door-interlock switches — a failed interlock prevents the magnetron from receiving power and mimics inverter failure
• Check the line fuse and thermal protector for continuity — an open fuse causes a no-heat or no-power condition
• Test the magnetron for continuity and shorts — a shorted magnetron will destroy a replacement inverter board within minutes of operation
• Inspect wiring harness connectors to the inverter for burns, looseness or corrosion

Part Details

Installation Notes

1. Disconnect power and discharge the high-voltage capacitor before touching any internal components.
2. Photograph all wiring harness connections and connector positions before disassembly.
3. Compare the new board with the original before installation — confirm connector positions and mounting points match.
4. Inspect nearby wires and connectors for burns or damage before installing the new board.
5. Test the appliance through a full heating cycle and check for error codes after restoring power.

Skill level: Advanced. Microwave appliances contain high-voltage components that can remain hazardous after power is disconnected. Service should be completed by a qualified appliance technician. Professional installation is strongly recommended.

Verified Compatible Models

JMC2427LL00, JMC2427LM00, JMC2430IL15, JMC2430LL00, JMC2430LM00, JMW2427LL00, JMW2427LM00, JMW2430LL00, JMW2430LM00, JMW3430LL00, JMW3430LM00, KMBP100ESS20, KMBP100ESS21, KOEC527PBS00, MMW9730FZ20, WOC54EC0HB20, WOC54EC0HS20, WOC54EC0HW20, WOC54EC7HB20, WOC54EC7HS20, WOC54EC7HW20, WOC75EC0HS20, WOC75EC0HV20, WOC75EC7HS20, WOC75EC7HV20, WOEC7030PV01

Fitment reminder: Match the complete model number, including suffixes and revision digits, before ordering. Fits only verified appliance models using W11578579 or former part W11504539 — contact us to verify your model before ordering.