Turn off Main Screen While Using External

i hate that i cant figure this out LOL

i have my intel imac hooked to a 52"lcd that i watch movies on and i want to turn off the imac screen because it sits right next my lcd and prevents me from having a nice dark room for movies.

i am currently covering it with a t-shirt hahaha

anyone know how i can have it play on the lcd but shut off the main monitor?

thanks

Not sure whether this will work as planned, but could you try Ctrl+Shift+Eject?

i will try this when i head home for lunch.

it seems like it would be the simplest of things but i haven't been able to figure it out.

hope this works

thanks

ok that just caused a temporary blank screen on both screens and then back to normal.

i forgot to mention that i am not using mirroring.

there has to be answer for this.

Am sorry, but no, you cannot turn off the screen. For Some reason, Apple won't let you turn off your main screen and use an external monitor of projector

The t-shirt idea isn't half bad.... I will try it my self!

Apple has also for some reason not allowed the backlit to go completely off on the iMac. With the notebooks however you can completely turn of the backlight.

goobimama said:

Apple has also for some reason not allowed the backlit to go completely off on the iMac. With the notebooks however you can completely turn of the backlight.

Click to expand...

i noticed this the other night when i tried the trick of using DVD player ( which although not bad for what it does it just doesn't do much) i went ahead and mounted my .iso movie so DVD player would play it and my iMac screen went dark like i thought i wanted. however it wasn't off it was just not bright.

WHY?

seems like a simply thing to me but then again so does a lot of other stuff

^^ Yep. The screen works, just the backlight is off. Dunno why this is...

I have a solution for you. But first...

Noooooo! Don't cover your iMac with a Tshirt. The crucial cooling vent is located at the top of the back side. It's fairly impossible to drape a T-Shirt over the iMac without blocking this vent. (FYI the intake is on the bottom, and can need occasional dusting.)

To dim your screen, use one of these two free apps:

Shades, which is purportedly better but doesn't work on Snow Leopard. Make sure you get the right app, there are two with the same name. (Shades 1.2b2 software download - Mac OS X - VersionTracker)

Brightness Control, which turns your screen a funny low-contrast tint, but will suit your needs just fine, and works with Snow Leopard (I have it on right now). (Brightness Control 1.0.4 software download - Mac OS X - VersionTracker)

Both are available on versiontracker.com

johninsf said:

I have a solution for you. But first...

Noooooo! Don't cover your iMac with a Tshirt. The crucial cooling vent is located at the top of the back side. It's fairly impossible to drape a T-Shirt over the iMac without blocking this vent. (FYI the intake is on the bottom, and can need occasional dusting.)

To dim your screen, use one of these two free apps:

Shades, which is purportedly better but doesn't work on Snow Leopard. Make sure you get the right app, there are two with the same name. (Shades 1.2b2 software download - Mac OS X - VersionTracker)

Brightness Control, which turns your screen a funny low-contrast tint, but will suit your needs just fine, and works with Snow Leopard (I have it on right now). (Brightness Control 1.0.4 software download - Mac OS X - VersionTracker)

Both are available on versiontracker.com

Click to expand...

ok i am lost as to how your post has anything to do with this thread?

- the t-shirt worked for years for me with no problems. i use istat menu and never had an unusually high temp.

- those dimming softwares look great but do not solve "turning off" the iMac screen while having the extended desktop full brightness

thanks though

Solving your initial question

You asked how my post related to your thread. Here's your initial question, about dimming (or completely blacking out) a monitor without interfering with other montitors:

fletch33 said:

i hate that i cant figure this out LOL

i have my intel imac hooked to a 52"lcd that i watch movies on and i want to turn off the imac screen because it sits right next my lcd and prevents me from having a nice dark room for movies.

i am currently covering it with a t-shirt hahaha

anyone know how i can have it play on the lcd but shut off the main monitor?

thanks

Click to expand...

The response I gave you solves the problem for people accessing their Mac by VNC or otherwise needing their screen to be dim in a darkened room. As long as this software will dim just your main screen, it will suit your purpose. I have to admit, I don't have multiple screens, so I can't test whether it dims all the screens equally. And now that I look at it again, Brightness Control specifically says it dims all your screens... so that might not work for you if it ends up dimming your LCD as well!

Maybe you need to make a feature request to have them add control over individual monitors, or maybe you can find another app that does this.
But definitely don't use the t-shirt as you said in your initial post.

Another easy idea

Another easy idea, if you aren't mirroring the two monitors, is to draw a big black rectangle in your favorite application, and position it so it covers the whole screen (except the menu bar, but pretty close). It won't be perfect, but might help...

If you find a better solution, let me know. I'm trying to darken my screen while logged in via VNC, so I can still use over VNC.

SwitchResX
http://www.madrau.com/download/latest/latest.html

I found this solution on another forum and wanted to verify that it does work on my iMac. I needed it for the same reason as the OP. It's not free, but $19 (as of today) isn't much to fix this shortcoming with iMacs. It took five minutes to setup proper hotkeys and whatnot.

There's a free trial (which I just tested with). Plan on buying now...

Shades vs SwitchResX

SwitchResX is pretty cool, but it doesn't seem to be able to disable the backlight any better than Shades. Using either program, the screen still has a glow to it. If you have Lion, I recommend Shades.

Disable Primary iMac monitor

fletch33 said:

i hate that i cant figure this out LOL

i have my intel imac hooked to a 52"lcd that i watch movies on and i want to turn off the imac screen because it sits right next my lcd and prevents me from having a nice dark room for movies.

i am currently covering it with a t-shirt hahaha

anyone know how i can have it play on the lcd but shut off the main monitor?

thanks

Click to expand...

So I finally figured this out after trolling a heap of posts and trying all kinds of terminal commands. The way I disabled mine was to CAREFULLY remove the iMac glass screen using some suction cups to release it from the magnets, remove the front bezel via a heap of Torx screws and then disconnect the LVDS LCD signal cable which is just below the LCD screen on my 24" 2009 iMac. (No need to remove the LCD in my case) Worked like a charm and now my external monitor is the primary.

There are three cables connecting most iMac screens - 4 on some of the new ones. The secret is finding the right cable to disconnect or it won't boot. The small one is a temperature cable. The others control signal. Most are buried beneath the monitor.

In my case the internal LCD monitor was flickering and I really wanted to use an external TV display without the flicker. Problem solved. It boots up to the TV screen and I log in from there.

Hardest part is removing the glass screen without breaking it. Don't try prying it off or it WILL break! Use a pair of suction cups. See other posts on the teardown of an iMac for tips.

Rich1234 said:

So I finally figured this out

Click to expand...

holy cr#$ dude i posted this in 2008 and couldnt believe my email when i saw a notice of reply but HAHA glad it worked for you. sold that iMac years ago and never looked back

Disable Primary iMac monitor

I'm really surprised that Apple hasn't made a simple software switch to solve this issue. There are a massive amount of posts on this problem. As iMacs get older a lot of LCD screens are going out and at $600+ for a replacement part its no wonder folks are looking at other options including use of external monitors and TV screens. In my case this older system is great for watching movies and playing music - especially if you replace the HDD with a faster SSD (or use two 2.5" drives if you get the right mounting kit and cables). A little effort keeps a useful system working - albeit in a slightly less demanding role!

Tips posted here for posterity and anyone else frustrated by the lack of an easy fix to a simple and common problem!