Model A1224 / Mid 2007 and Early 2008 / 2, 2.4, or 2.66 GHz Core 2 Duo processor

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Power supply I think?

I have an imac 2133 that won't start, following the secuense of start up, when I plug the cable to the AC outlet I get LED 1 ON, LED2 OFF, LED3 OFF, LED4 OFF.

When I press the ON button LED1, LED2 and LED3 go green for a very short instant and then everything is OFF even LED1.

Can this be something more than the power supply?

Thank you

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If the #1 LED is going off, it is failing, replace it first.

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.

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mayer - I have read many many questions with the same LED answer. I just replaced my iMac power supply, and what is happening now is LED 1 will come on for maybe 2 seconds after plugging into a wall outlet, and then (without touching the power button or anything remotely close to the iMac) it blinks, along with LED 2 and 3 for a brief second/blink of an eye. I am curious to know what is wrong? I am not pressing the power button....I am wanting to know what I need to replace rather than replace piece after piece and end up paying for a complete new iMac because I have to keep replacing parts. This almost sounds like what I am going through right now. I know the power supply is working, I guess is the logic board the next thing to replace....if then, what if it were something else....how would i know?

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@mayer can you checkout Shayne Kreutzer's comment. Thanks.

By the way I read your Rabbi Yitzchak Cohen: 40 years in Dallas. I to went to Dallas in the late 70's to learn , wasn't there as long as you(2 years) but it too changed my life and set me on my course on the narrow path . I went to a school called CFNI

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Shayne - what happens when you do press the power on button?

@jimfixer I'm familiar with CFNI. So you know why we end up here helping others . It's always nice to find another brother ;-)

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When I press the power button, nothing. Since the trickle power isn't there, it acts like the power supply but I have a new one installed. Next step is new logic board, I presume

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Shayne, are you saying the new power supply does not give you #1 green LED? If so do not go further. You may have gotten a bad supply! The unit is not getting power so you need to address that. Power strips go bad, wall plugs and circuit breakers need to be checked first. Do not even think about a logic board at this point.

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Bad install? Ok, I will contact the supplier and request a return and another power supply to be sent. I will then touch base., here. It gives the LED 1 then flashes all LED 1-4 and completely off, without me pressing a power button or touching the iMac right after plugging into multiple outlets. And pressing the power button does nothing. If I leave it unplugged for a minute and retry, same result. What would be considered a "bad" install @rany ?? Just curious to see what you might know what I might be missing when you say bad install.

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May be you missed or nicked something during installation. Happens all the time, both for seasoned techs and first time DIYers. Did you double check everything?

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I did, the only thing that I have not tested, because I figured it would fail, was to test using a multimeter. Someone/a friend of mine said an AC line filter or logic board....only reason I have asked what to do because it's my wife's iMac and I'd rather fix it than replace it. I have never heard of an AC line filter and I did have a previous iMac with a bad logic board with working PSU

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