Currently Being ModeratedJul 22, 2012 5:57 AM (in response to Charlie7)
do you have applications running at the time when your putting it to sleep?
Currently Being ModeratedJul 22, 2012 6:44 AM (in response to iTech - Cnsk)
No. I close all applications first, then I go to the Apple menu> Sleep.
Currently Being ModeratedJul 22, 2012 7:42 AM (in response to Charlie7)
Do you have external drives connected? They can take time to go into sleep mode
Currently Being ModeratedJul 22, 2012 8:18 AM (in response to RRFS)
Yes, I have an external drive connected by USB for backup using Time Machine.
Currently Being ModeratedJul 22, 2012 8:26 AM (in response to Charlie7)
Considering how slow USB is I wouldn't worry about it, you can do a SMC reset to see if that helps but I doubt it would. If you don't know how click iMac SMC and PRAM reset for instructions.
Currently Being ModeratedJul 23, 2012 2:08 AM (in response to rkaufmann87)
I did the SMC and PRAM reset and nothing has changed. It still takes 20 seconds before the screen goes black. I'm just wondering if all 21.5 inch iMacs are supposed to do that, or are there some that sleep immediately? But I am happy to hear you say that "I wouldn't worry about it." I wonder if I should disconnect my external time machine backup drive, and then see if it still takes 20 seconds to go black. Thanks. Charlie.
Currently Being ModeratedJul 23, 2012 3:12 AM (in response to Charlie7)
No it's not a good idea to disconnect the TM drive, I would recommend keeping it connected. A couple of things that may affect how quickly it sleeps is how many apps are running, personally I only have a couple of apps running at a time so my system goes to sleep almost immediately. Another thing I do is I only put the display to sleep, I have done this for 5 years and again it works great. Below is a screen shot my of sleep settings, also note I like to use keyboard shortcuts. One of my favorites is the Sleep Command which is Control - Shift - Eject which puts my display asleep immediately.
Currently Being ModeratedJul 24, 2012 3:58 AM (in response to rkaufmann87)
The only reason I ask about the sleep issue is because my previous iMac, 4,1 from 2006 when put to sleep seemed quieter. My new 21" iMac is still running when it's asleep. Something in there is running, I can hear it. Why does it keep running when it's supposed to be asleep? My old one didn't do that. If it's normal I don't care. But if it's not getting its proper good night's sleep, I'm worried about it. ;-) It's my baby. ;-)
Currently Being ModeratedJul 24, 2012 5:09 AM (in response to Charlie7)
I understand Charlie, well I'm not there to diagnose or hear it. You didn't mention this was a new machine, if it's less than 90 days old you have free AppleCare coverage (unless of course you already bought AppleCare for it) so you should give them a call. The phone number is in your owners manual. They can help you determine if there is a problem or not.
Currently Being ModeratedJul 24, 2012 1:07 PM (in response to rkaufmann87)
Thanks for your many suggestions. I'll call Apple support -- still under warranty. Thanks. Charlie Pinneo.
Currently Being ModeratedJul 31, 2012 2:44 AM (in response to Charlie7)
The problem of my iMac not sleeping for 20 seconds was solved by the installation of Mountain Lion 10.8. Now it sleeps immediately.