It runs but doesn't heat — magnetron, inverter board
The door won't latch — door switch
The panel is dead — fuse, control board
It sparks inside — magnetron
The light won't turn on — led light
The door is loose, sags, or won't stay shut — door hinge
The oven or broil setting won't heat — broil element, heating element, thermostat
The auto or sensor-cook settings guess wrong every time — temperature sensor
It overheats, shuts off mid-cook, or smells hot — thermostat
Documented failures
Door switch
Technician onlyVendor replaces this part if the microwave will not work even if the door is closed
Stop. DIY once unplugged and once a multimeter confirms which switch failed. If reaching the switch bank means opening the inner cabinet shell rather than a simple access panel, stop and call a technician instead.
Try this first — it costs nothing. Wipe down the latch hooks and strike plate — food residue there stops the door seating fully and mimics a bad switch.
Check, in this order
Confirm the door closes firmly and the latch hooks aren't bent before blaming a switch.
Test each switch for continuity in and out of the door-closed position — most microwaves have two or three separate door switches and only one may have failed.
Listen for a click as the door closes; a switch that doesn't click is the one to replace first.
Before you open anything
Unplug it — do not work on the door switches with the cord connected.
These are the safety interlocks that stop the magnetron when the door opens; match the exact part, not just 'close enough.'
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $8.49–$48.44 against $1,595.33 for a new machine (3.0%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Fuse
Technician onlyVendor replaces this part if the microwave will not work at all
Stop. STOP. Licensed technician only.
Try this first — it costs nothing. Test the outlet and breaker before assuming the fuse itself is blown.
Check, in this order
Test the outlet with another appliance first — a dead outlet or tripped breaker looks identical to a blown fuse.
Note whether the failure followed a pop or smell, which points at a diode or short rather than a simple overload.
Before you open anything
Unplug it before doing anything else.
The line fuse is normally reached by removing the outer cabinet cover, which exposes the high-voltage capacitor — this is not a simple bulb-style fuse swap.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $8.95–$50.75 against $1,595.33 for a new machine (3.2%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Led light
Technician onlyVendor replaces this part when the bulb is burned out
Stop. DIY on models with an external or cavity-accessible light housing. If the LED module is only reachable by removing the outer cabinet, stop and call a technician instead.
Try this first — it costs nothing. Nothing free here — a dead LED module needs replacing.
Check, in this order
Confirm it's the LED module and not just a loose connector by checking whether the cavity stays dark during a cook cycle too, not only with the door open.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $9.99–$16.40 against $1,595.33 for a new machine (1.0%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Magnetron
Technician onlyVendor replaces this part if the microwave will not cook properly
Stop. STOP. Licensed technician only.
No free first check for this one. There is no safe free check that gets closer to a magnetron diagnosis than the water-cup test above.
Check, in this order
Confirm the turntable, light, and fan all still run normally — everything running but nothing getting hot is the classic magnetron/HV-circuit signature.
Run a full water-load cup once: it should get hot within 60-90 seconds on high.
Before you open anything
Unplug it and leave it unplugged — do not touch anything inside the cabinet.
The high-voltage capacitor next to the magnetron can hold a lethal charge for hours or days even after the unit is unplugged. Only a technician with a discharge tool should open this compartment.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $104.60–$173.26 against $1,595.33 for a new machine (10.9%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Inverter board
Technician onlyVendor replaces this part if the microwave will not work at ll
Stop. STOP. Licensed technician only.
Check, in this order
Note whether the unit runs at full power only, or won't heat at any power level — inverter faults often show up as low-power settings all behaving like 'high.'
Rule out a straight magnetron fault with the same water-cup test.
Before you open anything
Unplug it and leave it unplugged.
The inverter board sits in the high-voltage circuit between the control board and the magnetron — treat it exactly like magnetron work.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $184.57–$235.99 against $1,595.33 for a new machine (14.8%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Control board
Technician onlyVendor replaces this part if the microwave will not work at all
Stop. STOP. Licensed technician only.
Try this first — it costs nothing. Test the outlet with a different appliance, and check the breaker, before assuming the board has failed.
Check, in this order
Rule out the outlet, the fuse, and a simple breaker trip first — all are cheaper and all present as a completely dead unit.
Note whether the display is fully dark or shows a frozen/garbled readout — that distinction matters to a technician.
Before you open anything
Unplug it and leave it unplugged.
Reaching the control board on most models means opening the same compartment that holds the high-voltage capacitor.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Weigh it - this part is a meaningful share of a new machine. Part $199.45–$260.66 against $1,595.33 for a new machine (16.3%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Door hinge
Technician onlyVendor replaces this part if the door will not open or close properly
Stop. STOP. Licensed technician only.
No free first check for this one. specific to the hinge, but confirm the latch isn't the real cause first — that one may be free to fix.
Check, in this order
Confirm it's the hinge and not the latch — sagging near the top or bottom points at the hinge, a door that pops open at the button points at the latch instead.
Before you open anything
Unplug it before doing anything, including looking closely at a sagging door.
On most built-in and over-the-range models, the hinge sits under the same outer shell as the high-voltage compartment.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $43.00–$48.22 against $1,595.33 for a new machine (3.0%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Broil element
Technician onlyVendor replaces this part if it is burned out
Stop. STOP. Licensed technician only.
Check, in this order
Confirm this is a broil/convection symptom, not a microwave-heat symptom — plain microwave mode heats fine but broil doesn't.
Look for a visible glow difference or a section of the element that stays dark.
Before you open anything
Unplug it and leave it unplugged.
On a combination microwave/oven, the broil element compartment is behind the same shell as the high-voltage side.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $95.99 against $1,595.33 for a new machine (6.0%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Heating element
Technician onlyVendor replaces this part if the convection setting on the microwave will not work properly
Stop. STOP. Licensed technician only.
Check, in this order
Confirm this is a convection-mode symptom — plain microwave heat works but convection/bake mode doesn't get hot.
Note any burning smell, which changes the urgency.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $55.99 against $1,595.33 for a new machine (3.5%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Temperature sensor
Technician onlyVendor replaces this part if the microwave will not work at all
Stop. STOP. Licensed technician only.
Check, in this order
Note whether the oven/convection side overshoots, undershoots, or never reaches set temperature — this pattern helps distinguish a sensor fault from an element fault.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $66.02 against $1,595.33 for a new machine (4.1%).Part cost only. A service call adds a regional diagnostic fee plus labour.
Thermostat
Technician onlyVendor replaces this part if the convection setting will not work properly
Stop. STOP. Licensed technician only.
Check, in this order
Note whether it cuts out mid-cook or refuses to reach temperature at all — both point here but mean different things to a technician.
Parts exist for this component and are deliberately not listed here: this is not a repair to attempt yourself.
Worth fixing? Repair - the part is a small fraction of a new machine. Part $35.05–$61.95 against $1,595.33 for a new machine (3.9%).Part cost only. A service call adds a regional diagnostic fee plus labour.
If you replace it instead
Configuration-matched to this machine (27, true, ~1.4 cu ft). Prices are UPC-verified Amazon listings, not estimates. Like-for-like replacement rarely pays for itself on energy alone — replace for fit and features, or because the repair maths above says so.
A candidate must match this machine's configuration (style, fuel and defrost class) before price or efficiency is considered. Prices are a snapshot from the date shown; availability is not monitored — check the retailer before buying.