Thanks for all the information.
When I woke it up and asked if it was asleep, it just growled at me
1. There is no light anywhere on my 2013 iMac 27".
2. The CapsLock trick works. I push CapsLock on my Apple Keyboard and the green led on CapsLock comes on. I manually sleep the machine and the green led goes out. This is useful to figure out what is happening. However, it's not particularly useful generally for me since I always disable the CapsLock function and have it be another Control key. (I'm old and learned on an IBM PCAT keyboard--best keyboard ever.) Also, one has to remember to push the CapsLock key to turn the light on to see it go out . . .
3. Also, for Harryb: My mac mini and my 2013 iMac are both running 10.8.5. However, the Energy Saver preference in System Settings are different as show in the attachment. I don't understand nor like this feature.
What I am trying to do is stop the machine from sleeping during the day (it runs Plex Server, if it sleeps, Plex Server isn't available), but have it sleep overnight. I ticked the box in Energy Saver to "Prevent computer from sleeping automatically when the display is off". Then I used the scheduling function to schedule sleep at 11:00 pm and to wake at 6:00am. My hope was that it would not sleep during the day, but the schedule would override the not sleep and put it to sleep at 11:00pm and wake it up at 6:00am.
After doing this, pmset shows the following:
Terrys-iMac
esktop tbrown$ pmset -g
Active Profiles:
AC Power -1*
Currently in use:
standby 1
powerbutton 1
womp 1
halfdim 1
hibernatefile /var/vm/sleepimage
autorestart 0
networkoversleep 0
disksleep 10
sleep 0 (sleep prevented by )
autopoweroffdelay 14400
hibernatemode 0
autopoweroff 1
ttyskeepawake 1
displaysleep 15
standbydelay 10800
Terrys-iMac
esktop tbrown$ pmset -g sched
Repeating power events:
wakepoweron at 6:00AM every day
sleep at 11:00PM every day
Seems right. However, it went to sleep overnight, but didn't wake up when I tried to use Plex at 7:00AM. I had to manually wake it with the keyboard.
Now that I know how to tell if it is sleeping, I'll verify that it doesn't sleep during the day.
Any ideas?