Symptoms
- Adapter buzzes or hums audibly while plugged in
- Buzzing gets louder under heavier load
- Adapter also feels warm or hot along with the buzz
- Buzzing started suddenly after months of silent operation
Likely causes
- CommonNormal coil or transformer hum under loadCheaper adapters especially can produce a faint audible hum that isn't dangerous by itself.
- PossibleLoose internal component vibratingAge or a manufacturing flaw can cause an internal part to buzz against the casing.
- PossibleAdapter is failing or degrading internallyA buzz that's new, loud, or paired with heat can indicate a component starting to fail.
- Less commonOverloaded circuit trying to supply more current than ratedPowering a device that draws more than the adapter can handle stresses it audibly.
What to do
- Note whether the buzz is faint and constant (often benign) or loud, new, and paired with heat (concerning).
- Feel the adapter body; if it's noticeably hot as well as buzzing, unplug it.
- Confirm the adapter's output rating matches what the connected device needs.
- Try the adapter on a different outlet to rule out a wiring issue on that specific circuit.
- If the buzz is loud, growing, or accompanied by heat, a smell, or discoloration, stop using the adapter and replace it.
- Keep a low, constant, cool-to-the-touch hum in mind as usually harmless, especially on older or budget electronics.
Tools and parts
- None required
Replacement power adapterSearch: “AC power adapter replacement”
When to call a pro
No professional repair for adapter internals; replace a buzzing, hot, or aging adapter rather than continuing to use it.
Safety
Use caution
Unplug and stop using any adapter that buzzes loudly, feels hot, smells burnt, or shows discoloration.