An iMac with no chime, fan, display, or light usually points to the power chain first: wall outlet, power strip, cable, internal power supply, or logic board. Work through the simple checks before assuming the iMac itself has failed.
This guide applies to Apple Silicon and Intel iMac models.
Does This Affect You?
Use these steps if pressing the iMac power button produces no visible or audible response, or if there are only faint signs of startup.
Check the Power Basics
- Confirm the power cable is firmly connected to the wall outlet or power strip and to the back of the iMac.
- Test the outlet with another device such as a lamp or charger.
- If using a power strip or surge protector, confirm it is on, then try the wall outlet directly.
- Inspect the power cable for damage, bent prongs, or exposed wire.
- Hold the iMac power button for 3 to 5 seconds, then release.
If you hear a chime, fan, or see any light, the iMac is receiving power and the issue may be display or startup-related rather than total power failure.
Power Cycle and Look for Signs of Life
- Unplug the iMac completely.
- Wait 30 seconds.
- Plug it back in.
- Press the power button once and wait 30 to 60 seconds.
- Listen for fan noise or startup sound and check for any display glow or rear light.
- If possible on supported older models, test with an external display to help distinguish display failure from startup failure.
Disconnect Peripherals and Reset Power Settings
- Disconnect external drives, printers, hubs, and accessories, leaving only keyboard and mouse if needed.
- Try starting the iMac again.
- On Apple Silicon iMacs, use the full unplug-and-reconnect power cycle; there is no separate SMC key reset.
- On Intel iMacs, reset SMC by shutting down, unplugging for 15 seconds, plugging back in, waiting 5 seconds, then powering on.
- On Intel iMacs that start but behave oddly, reset NVRAM with Option + Command + P + R at startup.
Repair and Safety Notes
Do Not Open an iMac Casually
Most iMac displays are bonded with adhesive, and internal power components can retain charge. Hardware repair should go to Apple or an authorized provider.
Likely Hardware Checks
For a fully dead iMac, technicians commonly inspect the power supply, logic board, and internal connectors.
Power Surge Clues
If the problem started after a storm, outage, or surge, mention that during service intake because the power supply may have taken damage.
Older Model Parts
Vintage or obsolete Intel iMacs may have limited parts availability, so check repair support status if the model is several years old.
Sources
- Apple Support: If your Mac does not turn on or start up
- Apple Support: Restart, update, or reset NVRAM on Mac
- Apple Support: Mac desktop repair support