Model A1312 / Mid 2011 / 2.7 & 3.1 GHz Core i5 or 3.4 GHz Core i7 Processor, ID iMac12,2

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Will not start. Tone sounds but will not start.

No start but tone sounds. Occasionally thin white n black lines appear on screen. Occasionally multiple tones sound but no start


Update (10/12/2016)


Sry on delay. Lost power from hurricane. iMac will now not start - I do hear the usual 2 tone electronic bizz buzz that precedes the startup bong. Kinda like it wants to but just can't.

A1312 100~240 v,50-60 Hz 4.0A.

EMC 2429

I am loathe to buy a new iMac and would love to fix this guy.

I have previously replaced the power supply that went bad after a lightening surge.


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Review these two Apple T/N's:

- About Mac computer startup tones

- About the screens you see when your Mac starts up

Can you give us a bit more detail based on these.


Hi fellas

Thx for your interest and info.

When I press the start button I hear the bizt buzt sound that precedes the startup bong tone.

No start up. If I press my ear to the iMac I can hear electronic hum. But that's it. No start up.

I'm capable of disassembly and replacing parts but advanced diagnostics and resoldering boards is beyond me.

Do I have the option of fixing my baby or am I done ?



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2 Answers

Chosen Solution

First Reset your PRAM

Here's how to reset your PRAM:

Shut down your machine. Yes, all the way down, not sleep or logging out.

Press the power button and then press command-option-p-r. ...

Hold those keys down until your Mac reboots again and you here the startup chime.

Let go of the keys and let your Mac reboot normally.

Next, to help narrow the issue, hook up to an external monitor and tell us what you get on that screen.

Please give us the Axxx number and EMC number from the bottom of your stand.

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Replace the GPU. Sounds like a graphics defect.

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Simon will be eternally grateful.
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