Model A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 or 2.8 GHz Core i7 Processor

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Does my iMac 2011 have dead GPU? Unusual symptoms

Hi there,

I know about iMacs 2011 tend to have dead GPU but I wish to know 100% before I start deep messing around in it.

So when power on - it has “chime” and black screen - I hear HDD is loading something - and nothing else happening.

When I insert my old MacOS Panther DVD to boot from it while connected to TV via minidiplay to HDMI cable (which 10000% works) then……….. it beeps 3 times - 2 seconds and then 3 beeps and so on (I know 3 beeps and………. 5 seconds is RAM problem) and I swapped with good know RAM and same thing.

I know to see video from MiniDisplay “drivers” must load up (so fully loaded Recovery or Login Screen) but what if HDD + LCD is dead?

I would do HighSierra USB install disk - but I have Windows 10 only and it is too messy to make install disk.

Those 3 beeps while macOS from DVD install is confusing me.

Thank You for help

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Lets give this a try, restart your system and press the T key to enter into Target Disk Mode. Do you see the FireWire and ThunderBolt icons on your screen?

Reference: Mac startup key combinations

You'll want to use a USB keyboard.


Black screen Dan :(



Hi Dan

So I've opened it up and......... I got SHOCK

NOT A SINGLE piece of dust inside - I've disassembled it completely - it is NEW inside - not a single piece of dust inside radiators - it is shiny inside - warranty stickers on GPU and CPU intact - GPU card is like NEW - not a single piece of dust - inside fans - they NEW - if I had Mac Pro I would check how long that HDD was on but I dont.

Even if someone wold submerge it - still there should be some marks of dust - but NOTHING





OK, very strange! Sounds like the system was very rarely used if at all..

In some ways that helps narrows down is issues.

Let’s check the onboard diagnostic LED’s what are they telling you?

Block Image

LED 1 - Indicates that the trickle voltage from the power supply is detected by the main logic board. This LED will remain ON while the iMac is connected to the AC power. The LED will remain on even when the computer has been shut down or put to sleep. The LED will turn off only if the AC power is disconnected or the power supply is faulty.

LED 2 - Indicates that the main logic board has detected proper power from the power supply when the computer is turned on. This LED will be ON when the computer is turned on and the power supply is working correctly.

LED 3 - Indicates that the computer and the video card are communicating. This LED will be ON when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.

LED 4 - Indicates that the computer and the LCD display panel are communicating. This LED will be ON when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.

Beyond checking the diagnostics!

First thing I would do is to replace the PRAM battery as it’s likely dead being unplugged from AC for more than six months would have drained it.

Then the question is what needs replacing beyond the PRAM battery is dependent on what the diagnostics tells us after we replace it.


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