iMac modell 8.1. will not boot, screen issues

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iMac modell 8.1. will not boot, screen issues

Hi!

My iMac 24" modell 8.1. (IC2D - 2,8 GHz) will not boot from install disc OS X 10.6. When I turn the machin on I hear the sound ok, then the grey screen appear with the black apple logo and the spinning wheel starts up. Then nothing happens. I hear that the superdrive is spinning up with the install disc, but nothing happens on the screen.

The screen has much flickering/distortion, so I removed the LCD display and checked all the three cables between screen and logic board to see that they are secured.

I have installed an 2 TB HD in this iMac formatted in Mac OS X extended journaled. The 4 LED lights on the bottom of the logic board are on and green. Remember back with my PM G5 that I had to push a cuda button, is there any such button on this iMac?

Any suggestions?

Posted on Jun 13, 2011 12:44 AM

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Answer 1

Eric Ross

Level 6

11,807 points

Jun 13, 2011 1:16 AM in response to Kaprolat

You need to start the iMac with the original DVD that came your with your computer. Then run disk utility to repair your hard drive and premissions. http://support.apple.com/kb/TS1417

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Answer 2

Kaprolat Author

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Jun 13, 2011 3:17 AM in response to Eric Ross

Hi Eric!

This iMac will not either boot from the original OS X install disc.

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Answer 3

roam

Level 6

13,631 points

Jun 13, 2011 5:32 AM in response to Kaprolat

Can you start up in safemode?

http://support.apple.com/kb/HT1455

Message was edited by: roam

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Answer 4

Kaprolat Author

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Jun 21, 2011 2:14 PM in response to roam

Hi

The iMac would not boot from original install CD with OS X 10.5 Leopard. I have tried holding down the C key during power on with the install cd in place in the machine. Sometimes I can hear the cd starting to spinning and the apple logo is visible in a grey screen and the spinning wheel starts up. But after a while nothing happened. I have reset the NVRAM and PRAM but I am not able to install the OS on the HD.

Any idea what to do?

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Answer 5

Kaprolat Author

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Jun 21, 2011 4:25 PM in response to Kaprolat

Hi

This iMac model 8.1 is now blowing all fans at high speed during startup and the fans would not slow down. Any clue what to do to get it back to normal?

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Answer 6

Eric Ross

Level 6

11,807 points

Jun 21, 2011 4:35 PM in response to Kaprolat

Try starting the iMac by holding down the option key when restarting your computer, it should give you the option to select the hard drive or your DVD drive, Note: You need to have the original DVD that came with your iMac.

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Answer 7

WZZZ

Level 6

13,220 points

Jun 21, 2011 4:57 PM in response to Eric Ross

Eric Ross wrote:

You need to start the iMac with the original DVD that came your with your computer. Then run disk utility to repair your hard drive and premissions. http://support.apple.com/kb/TS1417

No, you want to run DU from whatever version is on the boot volume. The original version it shipped with was 10.5, but if it's now 10.6, he wants to use a 10.6 disc to repair with.

For the video symptoms, I would run the Hardware Test, in extended from the 10.5 disc, if it will boot to that.

http://support.apple.com/kb/ht1509

And Roam's suggestion to try a Safe Boot is a must.

EDIT: Permissions Repair should be done -- and I don't think this is appropriate to do now, anyway -- from the normal boot volume, not from the DVD. And, certainly not from the original disc.

Message was edited by: WZZZ

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Answer 8

Kaprolat Author

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Jun 22, 2011 10:31 AM in response to WZZZ

Hi thanks for answer.

I have done this according to the recent post;

- removed the HD from the iMac and replaced it in my Mac Pro, then I formatted the HD and reinstalled 10.6.0 Snow Leopard without the updates.

- then I installed this HD with 10.6.0 in my iMac.

- reseated the NVRAM and PRAM.

- then I started the iMac and the machine came to the grey screen with the black apple logo, the spinning wheel started and after a while the spinning wheel froze and the screen distortion came back.

- then I inverted the install disc 1 that came with the iMac originally 10.5.0 and held the option key down at startup so I could choose to start from HD or CD. Both logo was visible at the screen the HD or install disc CD. No matter if I started from there either HD or disc 1 I did not pass the black apple logo and spinning wheel Beckett the machine froze again.

- then I started by holding the shift key down at startup so I could start the machine in safe mode. the apple logo and progress bar appeared and by 1/3 the progress bar stopped and the machine froze again. When the machine freezes the screen distortion appears.

Any mo suggestion to this quality machine?

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Answer 9

WZZZ

Level 6

13,220 points

Jun 22, 2011 12:13 PM in response to Kaprolat

Hard to say what might be going on, especially since it won't Safe Boot.

This model came with an NVIDEA 8800 GS GPU as optional, otherwise it's a Radeon HD 2600. I know there are lots of problems with the 8800s. If that's what you have, the graphics issues might point to that.

You might also try pulling and reseating the RAM.

I wonder if there's any way to run the Hardware Test for the iMac in FWTDM from the MacPro?

http://support.apple.com/kb/ht1661

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Answer 10

Kaprolat Author

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Jun 25, 2011 3:29 PM in response to WZZZ

Hi WZZZ!

I have tried pulling and reseating the RAM, it did not help either unfortunately.

The strange ting is that it would not install the OS X on the machine, even the HD is formatted in Mac OS X extended journaled...

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Answer 11

Kaprolat Author

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Jul 24, 2011 12:35 PM in response to WZZZ

Today I was able to start up this iMac in FWTDM through my MBP. After that I was able to run the AHT on the iMac. I ran the quick test and the advanced test, both with the result - NOTHING WRONG FOUND.

This irritates me a lot and I feel that the AHT must be a big joke.....

This iMac won't boot at all, the HD on the iMac was visible on the MBP through FWTDM and there was nothing wrong with the HD.

How can I go further into the problems with this iMac, it won't start up at all. The grey screen and the black apple logo with the spinning wheel is all that I see. After a while the spinning wheel freezes and the screen distortion is back.

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