How to force iMac screen to sleep?

March 13, 2006 9:27 PM

I have an iMac G5 (iSight) running Mac OS X 10.4. Is there a way to force the screen to go to sleep, but keep the computer running?

I'm running some transcoding and compression programs that keeps the machine at a constant 100% CPU usage for hours. While this is happening, the screen never goes to sleep like it should.

Is there a program or command line utility that can force the monitor to go to sleep, yet keep the computer running? I thought cmd-opt-eject would work, but that forcibly puts the entire computer to sleep, not just the screen.

posted by jaimev to computers & internet (12 comments total)

I'm glad you asked this, as I've been wondering the same thing. PowerMac G5 with an LCD Apple Studio Display. Hitting the button on my monitor forces the computer to sleep. On my second monitor, I can just hit the button to shut it off. (And on my iBook I can decrease the screen's brightness down to zero, but that's hardly a real solution).
posted by Robot Johnny at 9:31 PM on March 13, 2006

What I do is go to "system preferences">"energy saver". There are two scroll bars there. The first one says "Put the computer to sleep when it is inactive for..."; I set this one to "Never". The second one says "Put the display to sleep when the computer is inactive for..."; I set this one to 30 min. This puts my monitor to sleep after 30 min of inactivity, but keeps the computer running. I hope this is what you need.
posted by yugolplex at 9:39 PM on March 13, 2006

Hitting the button on my monitor forces the computer to sleep

There's an option in Display Preferences (I think) where you can change this behavior for the button on a Cinema Display.

Doesn't work with the iMac though.
posted by cillit bang at 9:39 PM on March 13, 2006

There's an option in Display Preferences (I think) where you can change this behavior for the button on a Cinema Display

The only options I have are to disable the buttons altogether. (But I have a Studio Display, not a Cinema Display, if that makes a difference).
posted by Robot Johnny at 9:55 PM on March 13, 2006

Just to clarify, yes...I've already set the Energy Saver preference panel to go to sleep after N minutes of inactivity, but the display refuses to go to sleep, perhaps due to the CPU being pegged at 100& activity. Hence, my need for a way to forcibly put the screen to sleep by some other means.
posted by jaimev at 11:41 PM on March 13, 2006

unplug the monitor.
posted by gemini at 12:08 AM on March 14, 2006

Oops. iMac. Nevermind. (thought I was soooo clever..)

The only other thing I can come up with is a totally black screen saver.
posted by gemini at 1:22 AM on March 14, 2006

On PowerBooks you can turn the backlight completely off using the brightness controls, which is almost as good as having the screen off (the actual LCD doesn't use much power or wear out on its own).

But I have a Studio Display, not a Cinema Display, if that makes a difference

I only know about the fancy aluminum ones.
posted by cillit bang at 1:42 AM on March 14, 2006

I've been wondering the same thing, and would love to see someone come up with a solution.

(And WOW, do people not read the question -- we're talking about an iMac here, people, not a Cinema Display or a Powerbook!)
posted by delfuego at 6:27 AM on March 14, 2006

I have an iMac Intel w/iSight, and yugolplex's answer works for me. My computer doesn't go to sleep until I desire it.
posted by rocketman at 6:37 AM on March 14, 2006

For a brief period, I had the same problem as jaimev (I have the iSightless iMac)--it had been blacking the screen automatically, then it stopped, then it started back up. I think the problem had something to do with a system update a month or so ago.

I'd make sure I was up to date on the system updates, reboot, and do an NVRAM reset just for good measure.
posted by adamrice at 6:38 AM on March 14, 2006

I installed the Do Nothing Screensaver, set the system so moving the mouse into the lower left hand corner of the screen activates the screensaver, then used the brightness buttons to turn the LCD brightness all the way off.

Does an iMac not have brightness controls on the keyboard? On a PowerBook the lowest brightness setting turns the lamp entirely off.
posted by bcwinters at 8:52 AM on March 14, 2006