Over-the-range, built-in trim-kit, drawer, and combination convection microwaves fail similarly despite their different mounting styles. Common failures include the magnetron (the part that generates microwaves), door switches that detect closure, turntable motors, and control boards. Microwaves have one component that makes DIY genuinely dangerous — the high-voltage capacitor — and we want you to know that before opening anything yourself.
How a microwave works
A microwave generates radio waves via a magnetron, which heats food by exciting water molecules. The magnetron requires very high voltage (around 4,000V) supplied by a transformer and stored briefly by a capacitor. Door switches confirm the door is closed before the magnetron can fire. A turntable rotates food for even heating. Each subsystem has its own failure modes.
What we typically fix
- 01
Not heating (runs but food stays cold)
Almost always a failed magnetron. You'll hear the microwave hum and the fan run, but food doesn't heat. Less commonly the high-voltage diode or capacitor has failed (these can fail safely, leaving the magnetron without power). Magnetron replacement is the most common microwave repair.
- 02
Sparking or arcing inside
Almost always metal in the wrong place — foil, a fork, a chipped enamel coating exposing bare metal in the cavity. Stop the microwave immediately if you see sparks; continued operation damages the magnetron and waveguide. After removing the metal, run a glass of water for 30 seconds to test.
- 03
Turntable won't spin
Most likely the turntable motor has failed (a small AC motor under the floor of the cavity). Less commonly the coupling between motor and turntable has broken or the support roller ring is missing. Easy fix once we have the part.
- 04
Won't start (door switch failure)
Modern microwaves have three door switches that confirm the door is fully closed. If any one fails, the microwave won't start. Symptoms vary — sometimes it starts then stops, sometimes refuses to start at all. We diagnose by testing each switch in sequence.
- 05
Loud humming or buzzing
Some hum during operation is normal. Loud or new humming usually means the transformer is failing or the cooling fan motor is unbalanced. Both are routine repairs.
Types of microwaves we service
Different builds fail in different ways. Here's what we see most often across each type.
Over-the-range (OTR)
Mounted under the cabinetry above the stovetop. Combines microwave with a range hood. Most common configuration in current kitchens. Slightly harder to service because we need to disconnect from the cabinet mounting and venting.
Built-in trim-kit
A countertop microwave designed to fit into a custom cabinet opening with a trim kit. Same internals as countertop, different installation. Pulling for service is moderate effort.
Drawer microwave
Mounted in a base cabinet at counter height, opens like a drawer. Common in high-end kitchens. More complex mechanism than other types (the drawer slide system is part of the appliance), more service points.
Combination convection / microwave
Adds a convection oven function alongside microwave. Common as a wall-mounted unit. Two heating systems in one cavity — more complex, more service points.
Signs your microwave needs repair
- Food heating slower than usual
- Food not heating at all even though the microwave runs
- Sparks visible inside the cavity
- Burning smell from the microwave
- Door doesn't latch firmly
- Loud new humming or buzzing
Try these before booking
Quick checks that resolve a meaningful share of microwave calls without a tech visit.
- 01
Inspect the cavity for metal or damage
Open the microwave and look for foil, exposed metal where enamel has chipped, or any metallic object. Remove if found. Inspect the waveguide cover (small mica plate, usually on one wall) for damage — replace if cracked.
- 02
Reset the microwave
Unplug from the wall for 2 minutes, then plug back in. Many control board hiccups clear with a full power cycle.
- 03
Check the door alignment
Slowly close the door and watch where it seats. If it's misaligned, the door switches won't all activate. Sometimes the door hinges have worn — visible by the door drooping or not closing fully.
- 04
DO NOT open the cabinet panel yourself
The high-voltage capacitor inside a microwave can store enough charge to be lethal even after the microwave has been unplugged for hours. This is genuinely dangerous DIY territory — we use grounding tools to safely discharge before any internal work.
Parts we can replace
Parts we commonly replace during a microwave repair.
- Magnetron
- High-voltage diode (with safety discharge)
- Capacitor (with safety discharge)
- Transformer
- Door switches (3 in most models)
- Turntable motor
- Turntable coupling
- Control board
- Waveguide cover
- Door latch assembly
- Cooling fan
Before our visit
What to do
- Unplug the microwave at the wall before our visit
- Don't open the back cover yourself
- Photograph any error code on the display
- Have the model number ready (door frame or back of unit)
Finding the model number
Model number is usually on a sticker inside the door frame (visible when door is open) or on the back of the unit. Drawer microwaves have it inside the drawer cavity.
Safety
Microwave capacitors store lethal voltage even after the unit has been unplugged. We use proper grounding tools to discharge before any internal work. Please do not open the cabinet yourself — there are no user-serviceable parts inside and the risk is real.
Why hire Mendwell for microwave repair
Same-Day Service
Fast turnaround across the GTA. We aim to get your appliance running the same day you call.
Emergency Repair
Fast response for urgent appliance breakdowns. We're here when you need us most.
Warranty on Parts & Labour
Every repair is backed by a warranty on parts and labour. We stand behind the work.
Customer Satisfaction
Your satisfaction is our priority. Personal service on every visit, every time.
Affordable Pricing
Transparent, upfront pricing with no hidden fees. Free estimates before any work starts.
Licensed Technicians
Skilled, licensed technicians ready to handle every repair with care and expertise.
Common questions
Specific to microwave repair.
Why does my microwave run but not heat food?
Is it safe to use a microwave with a cracked door glass?
Why do I see sparks when I run my microwave?
How can I tell if the magnetron is failing?
Are drawer microwaves harder to repair?
What's the typical microwave lifespan?
Do you service Sharp, Panasonic, Samsung, LG, KitchenAid microwaves?
Can I clean a microwave with vinegar?
Why is my microwave display blank?
My microwave is making a loud humming sound. Is it dangerous?
Worth knowing
How long microwaves last
8–10 years for residential microwaves. Magnetron failure is the most common life-ending issue. Premium built-in models (Miele, Wolf) often run 12–15 years with maintenance.
What we don't service
We work on residential microwaves. We don't service commercial high-power microwaves or industrial RF heating equipment.
Where we work
We dispatch microwave technicians across the GTA — often same-day. See all coverage areas →
Other things we repair
Washer
Front-load and top-load washer repair across every major and premium brand. Often same-day across the GTA.
Dryer
Electric and gas dryer repair, including ventless heat-pump models. Often same-day across the GTA.
Fridge
Built-in, counter-depth, French-door, and side-by-side refrigerator repair. Sealed-system work performed by certified technicians.
Freezer
Upright, chest, and integrated freezer repair. We handle defrost system, thermostat, and sealed-system faults.
Dishwasher
Panel-ready, integrated, and freestanding dishwasher repair with proper reinstallation under cabinetry.
Oven
Wall-oven, double-oven, and steam-oven repair. Calibration, igniter replacement, and control board service.
Stove
Slide-in, freestanding, dual-fuel, and pro-style range repair. Gas-line work coordinated with licensed installers.
Cooktop
Induction, radiant, and gas cooktop repair, including high-end integrated models found in custom kitchens.
Range Hood
Wall, island, and insert range hood repair. Motor replacement, fan balancing, and LED lighting service.
Wine Cooler
Dual-zone and single-zone wine refrigerator repair for built-in and freestanding installations.
Ice Maker
Standalone and built-in ice maker repair, including clear-ice and nugget machines.