No sound or one speaker not working: what to check

Record the symptom and check for a stop condition

Write down the equipment models, selected source and whether both speakers or only one are silent. Note whether the problem began after a connection or setting changed, and whether it occurs with more than one recording.

Stop using the equipment if there is damaged wiring, liquid exposure, a burning smell, electric shock, abnormal heat or repeated protection shutdown. Switch off and disconnect only when safe, and seek qualified service. The NAD C 268 safety instructions, safety item 19, identify damage and abnormal operation as reasons for service. Repeatedly restarting a protection fault is not a diagnostic method.

Check playback and controls first

A lit indicator proves neither that audio is playing nor that it reaches the selected input. Keep volume modest while checking:

• Playback: is the source actually playing, and does another familiar recording show the same symptom?
• Destination: is the phone, computer or streamer sending audio to the intended output?
• Input: does the amplifier's selected source match the connected socket?
• Controls: are mute, balance and any speaker-output selection set appropriately?
• Headphones: does an inserted plug mute speakers on this model?

Sony's no-sound guidance starts with power, playback and level checks. The Denon PMA-600NE front-panel guide provides a specific headphone-muting example. Control behaviour differs between products, so use the actual manual.

For TV digital audio, also check the supported format in the TV connection guide. Do not compensate for silence by turning all volume controls to maximum.

Inspect accessible connections with power off

Power down and unplug as the manuals require before reseating cables or working on speaker terminals. Check that compatible signal plugs are fully inserted, channels are connected correctly and speaker-wire strands cannot bridge terminals or touch the chassis. The Denon speaker-connection instructions explicitly require unplugging before this work.

Do not wiggle live speaker wires, join speaker negatives or connect two outputs. Powered speaker pairs and wireless systems have different connection arrangements; a proprietary link is not interchangeable with a conventional speaker cable. Use the connection map to identify the route before changing it.

Restore power at low volume and repeat the same short passage. If the symptom remains, change only one known-compatible source or signal cable and record the result. A change that removes the symptom implicates that path; it does not necessarily prove which component is faulty.

Optional: exchange a conventional stereo RCA input

Use this check only for a matching left/right pair of ordinary analog line inputs and when the equipment instructions allow it. Audioengine's A5+ Classic one-speaker FAQ uses this kind of input exchange to narrow a missing-channel problem.

1. Note the original arrangement and power down as required.
2. Exchange the left and right signal plugs at the receiving line input only. Leave their source ends and the speaker connections unchanged.
3. Restore power at low volume and replay the same passage.
4. Record the result, then power down before restoring the original plugs.

If the silence moves to the other speaker, investigate the source or cable path upstream of that input.

If it stays at the same speaker, investigate the receiving input and downstream path with manufacturer support.

Both results narrow the search rather than diagnose a specific failed part. Do not apply this procedure to speaker-output terminals, PHONO wiring, digital coaxial sockets or proprietary links just because their plugs look familiar.

Give support a useful record

Use one line per check: original symptom → one change → observed result → original arrangement restored. Include the exact models, selected source, connection labels and any indicator pattern interpreted through the manual.

Stop when the next step would mean opening a case, changing an unknown connection or guessing a reset or repair procedure. A short record of controlled external checks is more useful than many simultaneous changes with no known starting point.