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IMac with Snow Leopard doesn t work without second display connected

Hi,

I've a iMac 24" and I would like to resell it urgently.

But I've a big problem, if I disconnect my second display (belinea 20"), the iMac screen become grey or blue after many second.

If I boot system, after the grey clock : nothing, grey or black screen.

The Os is snow leopard disc, update version (10.6)
The iMac version is iMa8,1
The EFI bios is : IM81.00c1.b00

I tried :
Reinstall with format
Utility disc on boot cd (scan disk & rights repair)

Even when I try to boot cd without second screen, I ve white screen
(after a update to 10.6.4)

Help me please

MacPro4,1, HD4870

Posted on Sep 26, 2010 1:37 PM

Reply
23 replies

Sep 27, 2010 1:26 AM in response to rkaufmann87

Thanks, I will test your tip this evening.

At the last test this morning, after a PRAM reset (3 times), when I don't touch anything, the bug screen does not appear. But, when I launch a spotlight or anything else (like a Finder), I've a bug screen (a purple/pink screen this time).

And if I try a 10.5.2 install (delivered with the iMac), I've directly a grey screen after boot.

Do you think that I must install Snow Leopard update from 10.6 to 10.6.4 nevertheless ?
(the bug was present too with my last 10.6.4 install)

note : my graphic card is a nVidia 8800 GS

Sep 27, 2010 6:48 AM in response to Antonio Rocco

Hi Tony,

I don't how these instructions are the same, here is what the article says:



_Resetting PRAM and NVRAM_

• Shut down the computer.
• Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
• Turn on the computer.
• Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
• Hold the keys down until the computer restarts and you hear the startup sound for the second time.
• Release the keys.

Your original post said *"Restart the mac and depress the alt, command, P and R keys simultaneously. You should hear the boot chime. Keep the keys depressed until you hear the boot chime a further three times. On the final boot chime release the keys and let the mac boot normally."* How I understand your post that totals 4 chimes vs. the 2 Apple specifies. Am I missing something?

Message was edited by: rkaufmann87

Sep 27, 2010 7:17 AM in response to rkaufmann87

Not sure if this helps, but do a search in these forums or maybe a Google, I seem to remember there was a problem like it a while ago and lots of discussion about it. hopes this helps.

Alternatively you might run Apple Jack ( http://applejack.sourceforge.net/) there might be some funny stuff stored on your Mac over time and now that it hears it has to leave you it thought I dig out some trouble and see if I can stay. 🙂 no seriously AppleJack sometimes solves funny things like it.

Succes.

Sep 27, 2010 8:02 AM in response to Antonio Rocco

@Tony : So, I will test a 10 times reset PRAM this evening and post just after to tell you if is ok 🙂
@ChangeAgent : Ok, I will test your solution just after the PRAM reset, and maybe Onyx ?

I will test too :
- A SMC reset ?
- Detect monitor in "System Preferences > Monitors"
- Mirror video (check or uncheck) in "System Preferences > Monitors"
- "System Preferences > Startup Disk" and choose internal HD
- Apple Hardware Test

& return to this post if all of that doesn't work or work

Sep 27, 2010 9:43 AM in response to rkaufmann87

This always gets confused. It's a total of 3 chimes. The startup chime + 2 more. (But I don't think 4 chimes total does any harm.)

Antonio Rocco wrote: In my experience sometimes two PRAM Resets is not enough. I have done 5 or even 6 in the past after doing one or two and they have fixed the problem at that time. As long as it's two or more then you have a fighting chance of it possibly fixing the issue.


Tony, are you saying several PRAM resets may fix a problem where only one doesn't? Never heard this before. This is very interesting, if true. You mean reboot 2 or more times with PRAM resets each time?

Message was edited by: WZZZ

IMac with Snow Leopard doesn t work without second display connected

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