The answer, before the detail
On a Black+Decker AG microwave the useful first question is not what is broken but whether the oven has power at all. A dead display and a live display that ignores the start button are different faults with different lists, and the outlet is proved in seconds with something else plugged into it. On the AG models the check that decides the order below is which build you have: a glass turntable, or not.
What the owner actually sees
- No clock, no light, nothing — A power question — outlet, plug, breaker — before it is an oven question.
- The display is lit but start does nothing — Power is present and the oven is refusing: door, lock or panel.
- It beeps and clears what you entered — Push the door firmly shut and try again.
- A programme that begins and quits — Note whether the machine is hot when it happens.
- NEAR MISS — it runs but the food stays cold — That is a heating fault on an oven that has started, and it has its own page.
Most likely first on this family
- The outlet, the plug or the breaker — It leads whenever the display is dark, and it is dismissed in seconds by plugging something else into the same socket. A standard household branch circuit is 15 A or 20 A at 120 V and kitchens share theirs freely.
- The door is not latching, or an interlock is not made — It ranks high because it is also a safety fault in its own right. A door that has been knocked is the common history.
- A child lock or a demonstration mode is set — It rises in any household where the panel is within reach of children. An unfamiliar padlock icon is usually this.
- The touch panel or its membrane has failed — Mid-list: it explains a panel where some keys work and others do not, which nothing above it does. Grease and steam are what age a membrane panel above a hob.
- The control board, the thermal cut-out or an interlock switch — It comes last deliberately: it is what remains once power, door and lock are all clear. A thermal cut-out that has opened has a reason behind it worth finding.
Check in this order, and why
- Look at the display: lit or dark? — Dark sends you to the socket and the breaker; lit sends you to the door, the lock and the panel.
- Press the door firmly shut and retry — A programme that starts when you hold the door home has identified the fault without a tool.
- Read the display icons and any message — Holding the lock key for a few seconds usually clears it, and a demo mode has its own sequence.
Power off first
Safety
Never open the cabinet of a microwave oven. The high-voltage capacitor inside can hold a lethal charge long after the machine is unplugged, and nothing behind that cover is an owner part on any model. Unplug the oven before cleaning anything, leave every door interlock exactly as it is, and do not run the oven empty. If the door is damaged, if it has been dropped, or if the oven runs with the door open even for a moment, stop using it and unplug it.
Where the owner job ends
Call when the socket is proved with another appliance and the oven is still dark, or when the door and the locks are proved and it still refuses. What remains is the interlock switches, the thermal cut-out and the board, and all of them are behind a cabinet that is never opened by an owner because of the capacitor. Unplug the oven while it waits.
Other faults covered for the AG models
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
