Most of these calls should not become jobs
This page argues against itself for the first half, which is unusual for a service page and is the honest position. A countertop microwave is a commodity appliance costing less than most repairs, and calling anybody out to one is spending money badly. Everything changes when the appliance is screwed to the underside of a cabinet with a vent duct behind it, and that distinction is the entire subject here.
The one appliance where we usually say do not repair it, and the exception
Start with the case against. A countertop microwave is a mass-produced commodity. Attending one, diagnosing it and fitting a part costs more than most of them are worth new, and there is no arrangement of the arithmetic that makes it sensible. If yours stands on the worktop and it has stopped working, replace it. We will say so on the phone and we will not send anybody, which loses us the visit fee and is plainly the right answer.
Now the exception, and it is a large one in this market.
An over-the-range microwave is not a countertop unit in a different place. It is screwed to the underside of a wall cabinet, bolted through a mounting plate on the wall, wired into a dedicated circuit rather than plugged into a socket, and connected to the kitchen's extraction: either ducted out through the wall or the roof, or recirculating through a charcoal filter. It is a fitted appliance and it is part of the kitchen.
That changes the replacement cost in three ways at once:
- The aperture. Over-the-range units are near-standard at 30 inches wide, but the height between the hob and the cabinet above is not standardised, and the cabinet above is frequently a shortened one built for the original appliance. A replacement an inch taller does not go in.
- The duct. The exhaust connection has to line up with the existing duct, and models differ in whether they exit at the top or the back and which knockout they use. A mismatch means ductwork.
- The electrical connection. It is a hard-wired or dedicated circuit, which makes fitting one an electrical job rather than a plug-in.
Add those together and replacing an over-the-range microwave is regularly $600 to $900 fitted rather than the $250 the shelf price suggests. Against a repair at $130 to $310, the fifty percent rule stops applying, because the two things being compared are no longer comparable. The fifty percent rule was written about an appliance you can carry.
The same is true, more strongly, of a built-in microwave in a trim kit or a combination microwave and wall oven unit, both of which turn up in the newer south Charlotte, Waxhaw and Weddington kitchens. There the trim kit is model-specific and the aperture is joinery.

It runs but nothing gets hot: the real diagnosis
The commonest microwave complaint by a distance. The turntable turns, the light is on, the fan runs, the timer counts down, and the food comes out cold. That is a fault in the high-voltage side, and there are four candidates.
- The door interlock switches. Usually three of them, in series, and they are the first thing to check. A microwave will not energise unless every switch agrees the door is shut, and one failing open produces exactly this symptom. They are inexpensive parts and it is the most common cause. Worth knowing that a door which has been slammed for years, or a latch that has worn, will kill these switches repeatedly.
- The high-voltage diode. A cheap component that fails often, usually shorted. A classic sign is a loud hum or a buzz on start, with no heating.
- The high-voltage capacitor. Less common, and dealt with below.
- The magnetron. The tube that actually generates the microwaves. It is the most expensive part in the appliance and it is diagnosed last, not first, because the three cheaper components above account for most of these faults.
The safety part, which is not a formality
A microwave capacitor stores a lethal charge and it holds it after the appliance is unplugged. This is not the ordinary electrical caution that attaches to any appliance repair. It is a genuinely dangerous stored energy in a domestic box, at a voltage and a current that will kill, and it does not dissipate quickly on its own. Discharging it properly through a resistor before touching anything is the first step of every microwave job, and it is the reason this is the one appliance on this site where we would actively discourage a competent DIY attempt. There are plenty of things worth having a go at yourself. This is not one.
Other faults
A touch panel or membrane that has stopped responding is common on older units and the part is frequently discontinued, which ends the appliance. The turntable motor is cheap and easy. Sparking or arcing inside the cavity means the waveguide cover has burnt through, which is a $10 part and needs doing before the arcing damages the cavity wall.
The extraction, and the thing above a Charlotte hob
An over-the-range microwave does a second job that gets forgotten until it stops: it is the extraction over your hob. And in this metro that arrangement is close to universal in the post-2000 subdivision stock, because it saves a separate hood and a cabinet.
Two things go wrong with it.
It was never ducted in the first place. A large proportion of these installations are recirculating: the fan draws air through a charcoal filter and pushes it straight back into the kitchen through the vent at the top. That removes smell to a degree and removes essentially no heat and no moisture. Where a house was built with a recirculating installation and there is an exterior wall directly behind the appliance, converting it to a ducted one is genuinely worthwhile and is a moderate job.
Nobody changes the filters. There are two. The grease filters underneath are metal mesh and go in the dishwasher, and they want doing monthly. The charcoal filter inside the top is only present on recirculating installations, cannot be cleaned, and is meant to be replaced every six to twelve months. A blocked grease filter makes the fan work against a wall and it is the usual reason an over-the-range unit is noisy or feels weak.
There is a heat consequence too, and it is why these appliances have a shorter life than most: an over-the-range microwave spends its whole life directly above a hob, so its electronics live in rising heat from whatever is cooking below. Mean service life for one is nine to ten years, the shortest of any major kitchen appliance, and that is the reason. Where a control panel goes on a nine-year-old unit, the discontinued-part question arrives quickly, and we check it before quoting.
What the job covers in Charlotte
What we cover
Over-the-range and cabinet-mounted built-in microwaves, including the combination microwave and wall oven units common in the newer housing stock here.
Target outcome
A straight answer on whether the appliance is worth attending at all, and where it is, a repair carried out with the capacitor properly discharged.
Decision point
We tell people not to repair countertop microwaves, because an attendance fee against a replaceable appliance is not a service, it is a way of charging for a visit.