iMac Won't Turn On
iMac • Will not turn on / no power
Quick Answer
An iMac that will not turn on is most commonly caused by a failed internal power supply, a tripped thermal cutoff, or a logic board power circuit failure. Unlike MacBooks, iMacs draw power directly from the wall outlet, so a failed power strip, outlet, or power cable should be ruled out first.
Possible Causes
Power outlet or cable issue
CommonThe power cable may be loose, the outlet may be dead, or the power strip may have tripped. Try a different outlet and ensure the cable is fully seated.
Failed internal power supply
CommoniMacs have an internal power supply unit (PSU) that converts wall power to the voltages the logic board needs. These fail over time, especially after power surges. Symptoms: no power at all, or the iMac powers on briefly and shuts off.
Logic board power circuit failure
ModerateSimilar to MacBooks, the logic board has power management components that can fail. A blown fuse or damaged voltage regulator prevents the board from initializing.
Stuck power button
Less commonOn some iMac models, the power button mechanism can become stuck or unresponsive. The button may feel different (mushy, no click) if this is the issue.
After a power surge or outage
ModeratePower surges can damage the PSU and/or logic board components. If the iMac stopped working during or after a storm or power outage, surge damage is likely.
What You Can Try at Home
Check the power source
Try a different wall outlet (not the same power strip). Ensure the power cable is fully seated in both the iMac and the outlet. Try a different power cable if available.
Power cycle
Unplug the iMac from the wall, wait 30 seconds, plug it back in, wait 10 seconds, then press the power button. This drains residual charge and can reset the PSU.
Listen for sounds
When you press the power button, listen for any fan spin, chime, or hard drive noise. Any sound indicates the PSU is delivering some power and the issue may be display-related rather than a total power failure.
Check for LED indicators
Some iMac models have diagnostic LEDs on the logic board visible through the memory access door (older models) or by shining a light through the rear vent. If LED 1 is not lit, the PSU is not delivering power.
Reset SMC (Intel iMacs)
Shut down (or unplug if already off), unplug from wall, wait 15 seconds, plug back in, wait 5 seconds, press power. For Apple Silicon iMacs, press and hold the power button for 10 seconds.
When to Get Professional Help
If the iMac shows no signs of life after trying a different outlet and power cycling, the issue is an internal power supply or logic board failure. iMacs should not be opened by untrained individuals — the internal power supply carries dangerous voltages even when unplugged, and the display is bonded with adhesive that requires special tools to remove and reseal.
WarriorMac Repair Cost
Power supply replacement: from $149. Logic board power circuit repair: from $199. Free diagnosis — we only charge if we fix it.
Frequently Asked Questions
Can I ship my iMac for repair?
Yes. We recommend using the original Apple packaging if available. If not, use a double-walled box with at least 4 inches of foam padding on all sides. We can email you detailed packing instructions for your specific iMac model.
How much does iMac power supply replacement cost?
iMac power supply replacement starts from $149 at WarriorMac. If the issue is on the logic board instead, component-level repair starts from $199.
Is it worth repairing an older iMac?
It depends on the model and the repair cost vs. replacement value. We provide a free diagnosis and honest assessment. For many iMacs, a $149-$300 repair extends usable life by several years.