IMac display mirroring

I have an iMac G5 which is having some issues with video mirroring. When I try plugging a TV into it via the Apple video adapter, the imac display flickers, indicating it has adjusted to the new display, but there is no image on the TV. The System Preferences indicates that there is a "VGA Display" attached. (I believe that is supposed to say "NTSC/PAL." That is what my PowerBook says in any case)
Now however I have a new problem. The Apple Video Adapter is unplugged but the iMac still thinks that the "VGA Display" (actually the apple video adapter) is plugged in. It is stuck at a certain resolution (1028x768) and if i put it at a higher resolution it still shows only 1028x728 pixels, except now they are in the middle of the screen with a black border around it. (I believe this is normal behavior.... for when a TV is actually attached)
Any ideas? Both for the first problem (iMac thinks TV is a VGA Display) and the second (iMac thinks there's an external display attached when there is not). Thanks.
iMac G5, 1st Gen 1.8 GHz 17" Mac OS X (10.4.4)

Im having the same issues and would like to know if there is a solution...its driving me crazy!

Similar Messages

IMac display Mirroring to a MacBook

Hi everyone,
I am looking to mirror my iMac display to my macbook, as i need the extra screen space. I just got a thunder bolt cable to connect the two but i can not seem to connect them through target mode. Has anyone found a way to do this or does it only work the opposite way around?.

Target Display mode only works to display another device's screen on an iMac. Use a product such as ScreenRecycler over a network.
(122619)

Is there any way to turn on Video Mirroring if my iMac display is FUBARed?

Okay, my iMac display is permanently frakked.
Nothing else is wrong with the system (the tech assured me, anyways). Haven't yet used Firewire Target Mode to check yet.
Regardless, I have all the proper cables and adapters--and external VGA monitor--but no way (that I know of) to turn video mirroring on.
If I can't get an external display working, I'll be out either $900 to repair the display or $3000 for a completely new system.
Ideas?

Tried it and no go.
Not sure what's wrong.
Connect the VGA cord to the Mini-DVI-to-VGA adapter
Connect to external monitor.
Boot up iMac with adapter attached. Cmd-F1. Nothing.
Boot up iMac with adapter unattached, attach after boot is finished, Cmd-F1. Nothing.
Repeat, using a different USB port for my keyboard. Nothing (x2).
Repeat again, using a third USB port for my keyboard. Nothing (x2).
If I'm not doing anything wrong**, I can only conclude the techie was incorrect and there is something else besides "just the display" that is wrong with the iMac.
**Is the monitor even connected correctly if I continuously get a "no signal" message? Or is that only because the mirroring isn't enabled?

IMac won't offer display mirroring option when connecting to HDTV with Thunderbolt to HDMI cable

I have an iMac, and am trying to connect to my HDTV to use as a second display (mirror). I am using a cable with a Thunderbolt connector at one end, and an HDMI on the other. I know the cable works because I have used it with my MacBook on other TVs. When I use this on my MacBook, I simply open displays, and between the tabs marked "Display" and "Color" there is always an "Arrangement" tab to select. When I try this same setup on my iMac, the only two tabs I can see are "Display" and "Color" - the option to mirror disdplay (or recognize the HDTV in any way) simply doesn't exist.
I would welcome any help. Thanks much, Doug.

OK, yes your Mid 2011 has a Thunderbolt port.
Reset > the System Management Controller
1. Shut down the computer.
2. Unplug the computer's power cord.
3. Wait fifteen seconds.
4. Attach the computer's power cord.
5. Wait five seconds, then press the power button to turn on the computer.
and the > NVRAM and PRAM
1. Shut down the computer.
2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3. Turn on the computer.
4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6. Release the keys.
Then try connecting the TV to the iMac.

Is it possible to turn off imac display while mirrored display plays video?

I've set up a new 21.5" imac for my parents use in their living room and have connected their 52" lcd tv to the imac as a mirrored display.
One issue that i can't find a solution to is to find a way to turn OFF the imac display when they're watching content on the lcd tv. If they want to watch a film from the imac out to the LCD TV, they want to dim the lights and watch it, but the imac display being on in the dark room is distracting.
Is their any way (3rd party software??) to turn off the imac display while still being able to have the mirrored display running?

You should actually NOT use mirroring, although it would work OK on the 21.5-inch iMac because the screen resolution is identical to 1080p HDTV.
In System Preferences Displays pane Arrangement tab, turn mirroring OFF. This makes the HDTV screen extend the iMac's Desktop. In the diagram on that pane, it shows how the two screen arranged. The edge where they touch is where you can move your mouse cursor from one screen to the other. You can move the two screen around in the diagram, to match how the iMac and HDTV are located in the real world.
In System Preferences Displays pane Display tab, there will be a window for each screen. The 21.5-inch iMac's screen should be set to 1920x1080. The HDTV's screen should be set to 1920x1080 also, if it is a "1080p" HDTV.
To watch video content on the HDTV, first show the video playing in a window. Drag the window to the HDTV screen so that it is completely on that screen. Give the full screen command (usually Command-F). The video will play in full screen mode on the HDTV screen. In most video playing applications, such as DVD Player, QuickTime Player, iTunes, etc., the other screen (the iMac's screen in this case) will go black. It's not OFF, but it will display black.
Note: Some video playing apps have a preference setting for which screen gets the full screen. When playing video content in a browser window (such as YouTube or Hulu), when you go to full screen mode by clicking the +full screen+ button, the other screen will not go black.
As far as I know, there is no way to turn off the iMac display, even with mirroring turned OFF.

Putting iMac display to sleep, when using TV as a screen.

I have just connected my iMac to my 42" Panasonic 1080p TV, the connection was easy and is working fine. My questions relates to putting the iMac display to sleep when using the TV as a monitor, if I am watching You Tube, Sky Player or a DVD, I intend to use my TV as the monitor. Is it possible for the iMac to puts its display to sleep, whilst leaving the TV on. I played around with this today, however was unable to manage this.
Regards Craig

Hi Craig
There is no way to independently sleep either the iMac's Display or an attached Display/TV. However if in the Display Arrangement Preferences you set the attached Display or TV to be the Main Display and turn Mirroring Off, then FrontRow and the Full Screen Mode app's like, DVD player, QuickTimePlayer, etc. will black out the unused iMac display.
Dennis

Using iMac display as extended desktop?

Hi,
is it possible at all to connect a MacBook to an iMac display to extend the desktop (or mirror)?
Thx
JP.

Hi,
yep it works with one of my laptop, but not the other one for some reasons... still working on that.
Thanks
JP.

24" iMac display fault

Hello,
About 3 weeks ago my Early 2008 24" iMac's display appeared completely blank when I tried to boot it up. The first time this happened I could hear like a sizzling sound coming from inside the iMac near the top. At the time I tried to reboot it by holding in the power button a few times, each time the startup chime sounded but the screen stayed completely black. At first the sizzling noise continued then after a little while stopped completely. I also tried resetting the PRAM a couple of times to no avail.
I took it into the Genius Bar at my local Apple Store around two days later where they said that because it was old, they didn't keep the parts for it so I would need to go to an Apple Authorised Service Provider instead. They tried to run hardware tests via an ethernet cable to their server and an iPad, but still could not see anything on the display and were unable to find anything from the hardware tests. They also tried resetting the PRAM.
The genius advised me that it would be either the backlight (which was fairly inexpensive to fix) or the whole LCD panel (more expensive to fix) and that he couldn't be any more specific because they didn't have the parts.
I managed to access the hard drive fine via target disk mode. Also, just today I tried to connect it to an external monitor via a VGA cable and adapter however noting appeared on either screen, which after researching I discovered that this could be because I need to turn on display mirroring in preferences first, which obviously I don't know how to because I can't access the iMac.
Does anyone have any suggestions as to what this might be or anything I could try?
Thanks!

oliver.s wrote:
I managed to access the hard drive fine via target disk mode. Also, just today I tried to connect it to an external monitor via a VGA cable and adapter however noting appeared on either screen, which after researching I discovered that this could be because I need to turn on display mirroring in preferences first, which obviously I don't know how to because I can't access the iMac.
Does anyone have any suggestions as to what this might be or anything I could try.....?
By default, you should be getting at least an Extended Desktop with your same desktop image and no menu bar on the connected monitor.
Try a different Mini-DVI adapter, a different cable combination or a different monitor. Maybe a Mini-DVI to DVI adapter, DVI cable and a DVI monitor.
If you are getting nothing from the Mini-DVI output port, then you may have more than just a monitor issue.

Horizontal scan lines on iMac with mirror monitor

Hi, I just bought a second monitor which I'm mirroring, using a DVI cable. Everything looks and works great, but when watching video or iTunes visualisation, I occasionally see scan lines on the iMac display, but not the secondary. Also, dragging stuff around is jumpy and funny.
Here's the info from System Profiler:
*ATI Radeon HD 2600 Pro:*
Chipset Model: ATI,RadeonHD2600
Type: Display
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 256 MB
Vendor: ATI (0x1002)
Device ID: 0x9583
Revision ID: 0x0000
ROM Revision: 113-B2250F-212
EFI Driver Version: 01.00.212
Displays:
iMac:
Resolution: 1920 x 1200
Depth: 32-Bit Color
Core Image: Hardware Accelerated
Mirror: On
Mirror Status: Hardware Mirror
Online: Yes
Quartz Extreme: Not Supported
Built-In: Yes
2619:
Resolution: 1920 x 1200 @ 60 Hz
Depth: 32-Bit Color
Core Image: Hardware Accelerated
Main Display: Yes
Mirror: On
Mirror Status: Master Mirror
Online: Yes
Quartz Extreme: Supported
Rotation: Supported
Television: Yes
Could it be something to do with Quartz Extreme suddenly (?) not being supported on the iMac display?
Cheers!
Message was edited by: Darren Jeacocke
Message was edited by: Darren Jeacocke

Ok update.... I followed directions here http://www.macfixit.com/article.php?story=20081110225534811 and Quartz Extreme is supported on both now, but i'm still getting the ugly scan line.
Profiler now reads
*Chipset Model: ATI,RadeonHD2600*
Type: Display
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 256 MB
Vendor: ATI (0x1002)
Device ID: 0x9583
Revision ID: 0x0000
ROM Revision: 113-B2250F-212
EFI Driver Version: 01.00.212
Displays:
iMac:
Resolution: 1920 x 1200
Depth: 32-Bit Color
Core Image: Hardware Accelerated
Mirror: On
Mirror Status: Hardware Mirror
Online: Yes
Quartz Extreme: Supported
Built-In: Yes
2619:
Resolution: 1920 x 1200 @ 60 Hz
Depth: 32-Bit Color
Core Image: Hardware Accelerated
Main Display: Yes
Mirror: On
Mirror Status: Master Mirror
Online: Yes
Quartz Extreme: Supported
Rotation: Supported
Television: Yes
Something to do with Master Mirror/Hardware Mirror??

IMac HDMI 'Mirroring' problems with LG 'Full HD' TV

I have my 20” aluminium iMac connected via a mini-DVI/HDMI adapter to my LG 32LF7700 full HD LCD TV. In mirroring mode it’s pretty good, but I have two problems.
1. Even when I turn ‘Mirroring’ off from my Mac’s displays ‘Menu’ options I still have the ‘Snow Leopard’ desktop background on my TV, and my iMac’s mouse will not stay within the iMac screen area. The mouse can still move off the iMac screen into the TV area. Is there any way, apart from unplugging the TV HDMI cable, to revert fully to the iMac screen when I turn ‘Mirroring’ off?
2. When playing movies in 16x9 ‘full screen’ on the iMac the image is not quite full screen on my TV. I had a ‘HD ready’ TV before the LG one and it was possible to fill the screen. Am I missing something in the settings that would make 16’x9 full screen’ on the iMac give me ‘full screen’ on my TV. My TV is PAL, 1080p (or 1080i), and is properly detected by the iMac.
Thanks.

Perhaps you misunderstand the two display process with a Mac. There are only two modes;
Mirroring is when both screens display the same thing, so your HDTV is just perhaps providing a larger version of the iMac display for using from across the room. The other is Extended Desktop mode, which creates a wide Mac Desktop that extends from one display to the other, based on which order that you have arranged the two display icons in Sys Prefs/Displays. This is why your mouse will travel from one display to the other as it travels across this wide Desktop.
In addition to the order that you have arranged these Desktops, you can choose which one is primary by dragging the Menubar from one icon to the other in Sys Prefs/Displays.
As far as watching videos, I d not have two monitors upon which to test this, but I believe that you can adjust the two displays screen resolutions separately in Sys Prefs/Displays.
If you go to the Help menu in the Finder choose Mac Help. After it opens click the index in the upper right and go to D/Displays. You will find some explanations about using multiple displays with your iMac, including Extended and Mirrored modes.
Dah•veed

Broken iMac display - nothing visible - How to set up external display?

I have a 17" Core Duo 1.83 with a cracked screen. It boots but I can't see anything thru the cracks. I can access the system in Firewire Target Disk mode, which I used to wipe the HD and reinstall Leopard.
Is there any way to boot the iMac in Display Mirroring mode, so that I can set it up to use an external display? I have a 22" Dell connected via DVI and would like to use that.
I guess the ideal would be a keyboard shortcut to use at startup. I've seen on other boards that there is such a shortcut for the Macbook: Command + F4. But it doesn't work with the iMac.
I also have the Remote Control if that could be any help.
Would voice commands be an option? If so, how would I activate and use them, given that I can't see anything on the screen? I don't remember ever activating them, so I don't know if they'd be on at the moment.
My idea is to turn the iMac around with the broken screen facing the wall, then use it with the Dell monitor. Still lots of life left in the iMac with 2GB RAM, works very well with Leopard, still quite fast.
Any help would be GREATLY appreciated. Thanks.

Okay, looking good for now!
I found a thread on Mac Forums. Link: http://www.mac-forums.com/forums/apple-desktops/184101-help-broken-imac-external -screen.html
Guy explains how he solved problem of iMac with broken screen, connected to external monitor; you need a second Mac to do this.
I quote:
-- What u need to do is drag the menu bar from the iMac with broken screen in Sys Prefs/Displays to the Ext Display - which of course is not possible. So if you were to connect the damaged iMac by firewire to another Mac with an External display - start the damaged iMac in Target mode by holding T key after powering on. Then start the Mac with Ext Display and hold Option Key and select the damaged Mac to boot off - once that is going go into Sys Prefs/Displays and drag the menu Bar onto the External Display to make it the Primary one. Then shut it all down and connect the Ext Display to the damaged iMac and with luck you will be GO. --
I cloned my Macbook 10.5.8 system to the iMac HD and made it bootable. Seemed to be working fine. I then shut down both Macs. I connected an external display to Macbook. The Macbook and iMac were still connected via Firewire. I booted the iMac and pressed T, so it booted in TDM. After about 30 seconds I booted the Macbook and pressed Alt: the Macbook's and iMac's disks were available as boot disks. I chose the iMac's disk and waited.... Seemed a long time. But finally the external monitor came to life and I had the whole thing working, more or less.
The setup was in Extended Desktop mode, with the extended desktop on my external monitor. Luckily, a bit of the top of the iMac's screen was semi-visible, and I was able to open Display Prefs. I selected Mirrored Displays at first and then was able to work on the external display (and not thru the cracks). From here, I unchecked Mirroring and selected the external display as the main one. This worked just fine. I have a 23" full HD monitor and it looked great.
I then shut down both computers, disconnected Firewire, disconnected the monitor from the Macbook and connected it to the iMac. Then I rebooted the iMac. It booted up a lot quicker, but on startup it went back to Extended Desktop, with the iMac's display as the Main one. Again, I was able to open Monitor prefs, then clicked on Gather Windows, which put the pref window on the external monitor desktop too. Again, from there, I could make the external monitor the Main one.
Question: is there any way to make the iMac boot to where the external monitor is the Main desktop all the time and by default?
If not, maybe the worst case scenario is that I have to set display prefs to Mirrored before shutting down. Then after startup I could just make the external one the main display again.
Many thanks David.
P.S. forgot to say that when I set the external monitor as the Main one in display prefs, it all worked okay, except that when I opened System Preferences, the window opened on the iMac's screen, not the external one.
Is there a setting to make all windows, in all apps, open on the Main display?
Message was edited by: moonshot61

Why weren't we told that display mirroring would not work with a Mac older than 12 months?

Why weren't we told that display mirroring would not work with a Mac older than 12 months?

You were, just not directly. If you go to apple's mountain lion webpage, you'll see this note at the bottom:
1. AirPlay Mirroring requires a second-generation Apple TV or later, and is supported on the following Mac models: iMac (Mid 2011 or newer), Mac mini (Mid 2011 or newer), MacBook Air (Mid 2011 or newer), and MacBook Pro (Early 2011 or newer).
http://www.apple.com/osx/whats-new/features.html

Intel imac display glitch and involuntary restart

Just want to know if anyone else has experienced this specific problem, there are plenty of complaints about intel imac displays but I can't be bothered to sift through them all trying to find a match for my problem.
A couple of months ago I was watching a video in quicktime and noticed that my screen was glitching and flashing fragmented diagonal lines - like a commodore 64 loading type thing. Then the spinning-ball came up and a force quit didn't do anything so I had to force shut down. I started up and it occured again. Then the screen went blank/black, but still lit up, and restarted without me doing anything. It also got stuck during start up the second time this occured. I panicked and ran out to buy a 500GB external drive, backed up all of my work and then re-installed mac osx from disk, archive and install job. This seemed to sort it and for the following two months it seemed OK. No sign of any problems.
Since then I have updated from 10.4.7 to 10.4.10 (which I have suspicion that it screwed the firmware in my motu 828 firewire audio interface, costing me a £130 repair - but that's another painful story).
It happened again tonight (the screen thing, not the motu). And the ball came up and I couldn't do anything. Force shut down, restart - screen glitching again. Then I had 2 unexpected restarts, one getting stuck in startup. Then a successful startup but accompanied by the glitchy graphics, mainly red/pink pixellated diagonal lines flickering in and out. I ran a disk first aid - no problems. Did a disk permission repair. Shut down and ran a hardware test, the first few minutes of the test the screen was still at it but then stopped glitching, hardware test found no errors (it was an extended test too). Now I'm back on it and it's all OK.
Any suggestions/similar stories?
When it occured 2 months ago I had the original ram that came with the imac. Now I have 2x1GB sticks of crucial ram.

That's it! Well, that's what I have. Unfortunately, I don't know about the cause, but I don't ever recall having it prior to an update going back about a year ago. I recall an update, and that update being immediately followed by some sort of Apple Graphics something-or-other. I feel pretty certain that's when I first noticed this. I just had my LCD replaced for another reason, but I think you'll agree, it's not an LCD issue. In my case, browser activity, scrolling up or down in a page, seems to be the most common trigger. I've also seen "pieces" of the torn page, on the screen when minimizing the browser to the dock (usually Firefox, but I think I've seen it with Opera and Safari too). Is there a way to find update packages installed somewhere? I'd know it if I saw it, and I'd definitely try removing that suspect package/update.
Message was edited by: geekboy2000 - corrected OS

User Contributed Tips in Intel-based iMac Your Intel-based iMac Display

*The following User Contributed Tips are located in the Intel-based iMac > Your Intel-based iMac Display forum:*
a brody - Using a second Mac as a display for a first
http://discussions.apple.com/thread.jspa?threadID=1587927
Publish date: July 7, 2008
*The following related tips are located in other areas of Apple Discussions:*
See also User Tips Library

My 20" 2.16 GHz Intel Core 2 Duo had become almost useless due to freezes and crashes- with NO crash reports in the logs.
They were often preceeded by video glitches, so I assumed it was a bad video card- unfortunately soldered to mother board.
Apparently, from forum postings, this is not an uncommon problem. The computer would run longer if the day was cooler, but rarely more than 10 minutes, so I suspected it was aggravated by heat.
Then I found this post from Bodomann on an Apple Support forum:
"Following up on my previous posting regarding my son's late model 2006 iMac that required a $900 logic board replacement:
Turns out the problem is apparently related to a bad CPU temp sensor. I installed 'iMac Fan Control' (Google it) which reported the CPU temp always at 32 degrees Fahrenheit (obviously incorrect). The same software allowed me to adjust the CPU fan manually. After multiple trials I set the CPU speed to 2800RPM after which the system would run forever - never freezing with the dreaded grey box 'reboot me' screen. I tried several times reverting the software to default speeds and the system would always crash within 10 minutes. "
I downloaded free Fan Control 1.2 for Imac from Derman Enterprises (they have an Intel iMac and a Mac Book/Pro version). It installs as a system preferences control panel. I cranked up all three fan speeds. The fans sped up noticeably. Horizontal lines have gone from screen (so far), no color artifacts and no crashes yet. I may have a real computer back! Hope Apple checks this out-
The control panel also gives the temps sensors are reporting at the CPU, hard drive and DVD drive. The CPU sensor reports the CPU temp as 32 degrees F- which is clearly wrong, unless Apple has been installing little refrigerators inside.
So thanks to Bodomann for posting- Hats off and three cheers to Derman and Cristoph for source code.
http://www.derman.com/iMac-Fan-Control
http://www.lobotomo.com/products/FanControl/index.html

When streaming a movie from an imac to apple tv, is there a way of putting the imac display off? I find it a waste having the screen on in another room. Any advice?

When streaming a movie from an imac to apple tv, is there a way of putting the imac display off? I find it a waste having the screen on in another room. Any advice?

No problem.
This is a user forum so you are not addressing Apple. There's nothing to fix, that's how home-sharing works. There would be no way for the ATV to recognize your library and display content if the computer is in sleep mode.
You can always airplay from an IOS device or use icloud if you don't wish to keep the computer on.

IMac display mirroring

Similar Messages

Maybe you are looking for