After unplging my Imac from power outlet with out manualy turn on its not turning on I did 10 second push the botton on the back , I disconect power and wait 15 second its not turning on any one can help

It really helps to know the exact model of the iMac since more recent models 2019+ have other modes & options. You can get the exact model by entering the system serial number here:

Check Your Service and Support Coverage - Apple Support

If you have a 2019+ model, there is a chance it was accidentally put into DFU Mode. Even if that did not happen, then the only other option available may be to put it into DFU Mode in order to "Restore" the firmware which will reset the T2 chip & firmware as well as pushing a clean copy of macOS onto the internal drive (or it may require you to use Internet Recovery Mode to reinstall macOS). The end result is all data on the internal drive will be destroyed. You could try a "Revive" instead which should not destroy any data, but will still reset the T2 chip & firmware, but in my experience a "Revive" has never helped with anything.

If you have an Intel Mac, then also try a PRAM Reset (hold for two chimes if possible...some models may have trouble with just one chime).

With either an Intel or Apple Silicon Mac, try connecting an external display to see if anything is shown on the external display. Maybe even try to toggle display mirroring by using Command + F1 although this may not be available until after logging in.

For any special startup boot keys like the PRAM Reset, Safe Mode, etc. you should use a wired keyboard.

Hey there micro818!

If your iMac is not turning on even after performing a reset by holding the power button on the back and disconnecting the power, there are a few additional steps you can try:

1. Check the power source: Make sure that the power cable is securely plugged into both the iMac and the power outlet. Consider trying a different power outlet or using a different power cable to eliminate any issues with the power source.
2. Reset the SMC: The System Management Controller (SMC) is responsible for managing power-related functions on your Mac. To reset the SMC on an iMac, follow these steps:

• • Shut down your iMac.
  • Unplug the power cord from the back of the iMac and wait for 15 seconds.
  • Plug the power cord back in.
  • Wait for an additional 5 seconds, then press the power button to turn on the iMac.

1. Check for signs of power: Look for any indications that your iMac is receiving power. For example, check if the power LED on the iMac's front is lighting up or if you hear any fans running. If there are no signs of power, it might be an issue with the power supply or internal components, and you may need to contact Apple Support or take your iMac to an authorized service provider for further assistance.
2. Try booting into Safe Mode: If your iMac is partially powering on but not starting up completely, you can try booting into Safe Mode to rule out any software-related issues. To do this, follow these steps:

• • Press the power button to turn on your iMac.
  • Immediately press and hold the Shift key on your keyboard.
  • Release the Shift key when you see the Apple logo or a progress bar. This may take a bit longer than usual.
  • If your iMac successfully boots into Safe Mode, you can try troubleshooting the issue further by identifying and resolving any problematic software or settings.

Let me know if it doesn’t fire up,

DX-7