The short answer
A Black+Decker microwave showing this usually tells you one thing: most microwave noise is the turntable, the tray or the vents — all of them reachable without opening anything. Reseating and cleaning are free and fix the majority. Noise from inside the case is where owner work stops entirely.
What you actually see
- A grinding or scraping under the floor of the cavity — A sound from below the glass tray is the turntable drive rather than anything electrical.
- A loud buzz that only happens while heating — A buzz under load is the high-voltage section working, and its volume varies between ovens.
- A hum that continues after the cycle ends — A fan running on after a cycle is normal on many ovens and is not a fault.
- A sharp crack or pop during heating — Popping is usually the food rather than the oven, and it is worth ruling that out first.
Causes, ranked for this microwave
- Glass tray or roller ring seated wrongly — The usual answer. the tray sits on a plastic roller ring driven by a coupling in the floor, and any of the three sitting off-centre clatters immediately. Rule it in or out properly here; a maybe at this position costs an hour further down.
- Food debris under the roller ring — The runner-up. it is common, cheap and easily missed because the debris is hidden by the tray. Getting a definite answer here is worth more than a quick look at the three below it.
- Roller ring or drive coupling worn — Third. the plastic wheels flatten and the coupling teeth round off with age, and both make noise before they fail outright. If this is the answer, the rest of the list stops mattering entirely.
What to check, in order
- First — the tray and its roller ring — Turn the tray by hand. A tray that lifts and drops as it turns is not on its coupling.
- Second — the cavity floor — Remove the tray and the ring and wash both, then wipe the cavity floor and the coupling clean and dry.
Checks an owner can do safely
- Step 1. Press the case while it runs — A flat hand on the top of the case that silences the noise identifies panel resonance rather than a component.
Tools: noneAbout 5 min
- Step 2. Clear the vents — Move the oven so every vent has clear air and nothing is stored against the case where air is drawn in.
Tools: noneAbout 10 min
- Step 3. Remove and refit the tray and roller ring — Lift both out, check the ring rolls freely, wash and dry them, and refit the tray so it seats onto the coupling rather than resting on it.
Tools: noneAbout 10 min
Before you open anything
Safety
Unplug it, and treat the inside as off limits. The high-voltage section of a microwave remains dangerous with the power disconnected. A damaged door, a bent latch or a failed switch is a reason to stop using the oven, never a reason to work around it.
When this becomes a service call
Stop and call when the next thing to do meets any of these. A fan that is seized rather than obstructed, or a noise accompanied by a smell or a spark, means unplugging the oven and stopping.
Sources
General guidance- The Control of Hazardous Energy (Lockout/Tagout) — OSHA 1910.147 and manufacturer service manuals, fetched
Nearest pages
What this page does not cover
Treat what follows as the class-level answer for a Black+Decker microwave. It will not tell you which board your unit has, which part number fits it, or what a particular code means on a particular family, because those differ within the range. The family and model pages beneath this one carry that, and they are linked under Related pages.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
