The short answer for B models
On an Avanti B microwave the electrical symptoms worth separating are the ones that appear at rest and the ones that appear under load. A breaker that trips the moment the oven is plugged in is a different fault from one that trips only when it runs, and a technician will want to know which you have.
Symptoms, and the ones that mean something else
- The plug or the socket is hot to the touch — A connection fault outside the oven, and it is a fire risk in its own right.
- A hot or acrid smell during or after use — Overheating insulation or a component, and a reason to stop immediately.
- The oven runs but the house RCD trips intermittently — A leakage fault, which needs a technician with the right instrument.
- Lights dimming elsewhere in the house when it starts — A heavy load on a circuit that is marginal for it.
- NEAR MISS — food is cold but nothing else is wrong — That is a heating failure and it is not an electrical safety problem.
The ranking for this family
- High-voltage component shorted — Ranked first for a breaker that trips under load, because that is the only section of the oven that draws heavily enough to do it.
- Circuit shared with other heavy loads — Nothing is broken; the circuit is simply being asked for more than it has.
- Control board failure — Last on the list, and it rarely presents as a tripped breaker.
- Waveguide cover burnt through — Food residue on the cover chars, then arcs, and it is a known and preventable cause.
- Earth fault in the appliance — A tingle from the cabinet or an RCD tripping, and the oven should be unplugged and left.
The order that saves the most time
- Where to begin — The order below follows the ranking rather than the machine: one of the five causes above cost nothing to rule out on B models, so they come first.
- Look inside the cavity for foil, metal trim or damaged paint — Arcing inside the cavity usually has a visible cause that an owner can identify.
- Stop and leave it unplugged once you have a description — Beyond this point every test needs an instrument and training.
- Feel the plug and the socket after use — A hot plug is a connection fault outside the appliance and needs attention on its own account.
Before you do anything else, unplug it
Safety
Unplug the microwave at the socket before you examine anything, and keep the case closed. The capacitor in the high-voltage section can hold a lethal charge after the power is off. Do not run the oven empty, do not defeat any door interlock, and take the appliance out of service entirely if the door is damaged or the oven runs with the door ajar — the door is what contains the energy.
Models in the B family
Reference| Model number | Family key |
|---|---|
| B20PXP78 | avanti:microwave:b |
When to call a technician
The line on a microwave is the outer case, and it is absolute. Cleaning, vents, settings, the clock and the child lock are yours; everything else is a service call.
Other B problems we cover
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
