Your over-the-range microwave is humming but the food stays cold, or it threw sparks and a puff of smoke. Call Acdc Appliance Repair and we connect you with a licensed, insured independent pro near Derry who services OTR, built-in and drawer microwaves.
A microwave is not a toaster. Inside the cabinet sits a high-voltage capacitor that can hold a lethal charge long after the plug is pulled, which is why this repair belongs with a trained technician and never with a screwdriver and a video.
We run a free referral line for homeowners. A dispatcher hears what the microwave is doing and connects you with an independent local technician who knows both the high-voltage side and the installation side of these units.
The contractors in our network are independent businesses that carry the license and insurance local rules require. Ask to see both at the door.
A magnetron or control board for a built-in can be a real expense. The technician writes the quote before any work starts, so you can compare it to a replacement unit and decide.
We look for a pro already working near Derry. A same-day slot opens up regularly when local pros have breathing room, and the arrival window gets set while you are on the line.
Expect an insulated discharge tool for the capacitor, a multimeter for diode and transformer checks, the model tech sheet, and a microwave survey meter to check for leakage after high-voltage work.
This is the work we route for OTR, wall-mounted, drawer and convection combo microwaves. Every job starts by safely bleeding the capacitor before a single meter lead goes in.
Everything seems to run except the heating. That points to the high-voltage circuit: a failed magnetron, a shorted diode, an open capacitor, or a burnt transformer winding. The pro checks each part with a meter after bleeding the stored charge.
Blue flashes along the side wall usually come from a greasy or burnt waveguide cover, chipped cavity paint, or a damaged rack support on a convection model. Left alone, arcing can pit the cavity and ruin the magnetron.
Microwaves use a chain of door interlock switches plus a monitor switch. When a switch sticks, the monitor switch shorts the line on purpose and blows the line fuse, so the whole unit goes dark. A unit that runs with the door open needs to be unplugged right away.
When keys stop responding or the oven refuses to shut off at zero, the touchpad membrane or a welded relay on the control board is usually behind it. The pro tests the keypad matrix and the relays first so the right part gets ordered.
Because an OTR unit doubles as the hood over your cooktop, the vent side wears out too. The technician can replace a noisy fan motor, a burnt cooktop lamp, clogged grease filters, and the charcoal filter used on recirculating setups.
A plate that will not spin usually needs a turntable motor or a new coupler. OTR units that sag or rattle may have a loose wall bracket or top bolts pulled through the cabinet, which is a safety issue with a hot stove below.
Use this as a quick read before you call. Share what you see with the dispatcher, and the technician can bring the most likely parts.
| Symptom | Common cause | What the tech checks |
|---|---|---|
| Runs, light on, no heat | Magnetron, diode, capacitor or transformer failure | Each high-voltage part with the capacitor discharged |
| Completely dead, no display | Blown line fuse from a failed door switch | Fuse, interlock switches, monitor switch |
| Sparks or smoke inside | Burnt waveguide cover, chipped cavity paint | Cover, cavity surface, stirrer, rack supports |
| Keeps running at zero or with door open | Welded relay or failed interlock | Control board relays and door switch chain |
| Plate will not turn | Turntable motor or coupler | Motor continuity, coupler, roller ring |
| Vent fan loud or dead | Fan motor bearings, greasy filters | Fan motor, damper, grease and charcoal filters |
A basic countertop microwave usually is not worth a service call, and most technicians will tell you so on the phone. Over-the-range units, built-in wall models, drawer microwaves and convection combos are a different story. They cost more, they fit a cutout or bracket, and swapping one means trim kits, cabinet work and a vent connection.
Unplug it, leave the cover on, and call. A dispatcher answers day and night.
Let the dispatcher know if the unit is over-the-range, built-in, a drawer or a combo, and describe the symptom. The model number is usually on a sticker inside the door opening, and having it speeds up parts.
We route the job to an independent pro near Derry and give you the arrival window on the call. When the schedule cooperates, a technician often arrives the day you call.
The technician unplugs the unit, discharges the capacitor with an insulated tool, and tests the high-voltage parts, door switches and control board. OTR models may need to come off the wall plate for access. You get a written, upfront quote before work starts.
Once the part is in, the technician runs a water heating test and, if the high-voltage side was opened, checks the door edges with a leakage survey meter. The technician typically documents the parts and labor warranty on the work order; ask for a copy.
Our over-the-range microwave went completely dark mid-popcorn. The technician found a blown line fuse, then traced it to a cracked door switch. He replaced both and showed me why the fuse would have blown again if he had only swapped the fuse.
The built-in in our wall oven stack hummed but did not heat. A new one would have meant a new trim kit too. The tech tested the diode and magnetron, replaced the magnetron, and checked for leakage with a meter before he left.
Sparks were jumping off the side wall every time I warmed soup. It was a burnt waveguide cover soaked with grease. Quick fix, and he showed me how to keep that cover clean.
Our microwave drawer would not stop running after the timer hit zero. The pro found a welded relay on the control board, ordered the board by model number, and came back two days later to install it.
When the light, fan and turntable all work but food stays cold, the high-voltage circuit has failed. The most common causes are a bad magnetron, a shorted diode, an open capacitor, or a burnt transformer. These parts carry lethal voltage, so let a trained technician test them.
No. Stop using it until it is checked. Sparks usually come from a dirty or burnt waveguide cover or chipped cavity paint, and continued arcing can damage the magnetron. If there is smoke, keep the door closed and unplug it if you can reach the cord safely.
A totally dark microwave often has a blown line fuse. The fuse usually blows because a door interlock switch failed and the monitor switch shorted the circuit on purpose. Replacing only the fuse is not enough; the technician tests the whole switch chain.
Often, yes. OTR, built-in and drawer models cost more and are sized to your cabinets, so replacing them can mean new brackets, trim and vent work. Countertop units are usually cheaper to replace. The technician gives you a written quote so you can compare.
Please do not. The high-voltage capacitor can hold a lethal charge long after the unit is unplugged, and a slip with a screwdriver can be fatal. Leave the cabinet closed and let a trained pro use an insulated discharge tool.
You should request it after any magnetron, door or high-voltage repair. Many technicians run a survey meter around the door edges and vents as a final check that nothing is leaking.
We route microwave calls from houses, condos and apartments throughout Derry and nearby neighborhoods. Dispatchers send each job to an independent pro already working close to your address, which helps when an OTR unit needs a second set of hands to lift off the wall plate.
Someone answers around the clock. Calls after hours are typically scheduled for the first slot next morning, while daytime calls can become same-day visits when a nearby pro has room.
