Model A1225 / Mid 2007 and Early 2008 / 2.4, 2.8, or 3.06 GHz Core 2 Duo processor

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Blank screen, no chime, only#1 LED = New Logic Board?


I’m running a 2.4 Ghz Intel Core 2 duo with 3Gb 667 Ddr2 ram, ATI Radeon HD 2600 Pro.

After reading many forums online, I have decided to ask for a second opinion of what I have made as a self-diagnosis. The logic Board needs replaced. Therefore, here is the back-story:

A week ago the comp starting having freezing issues, acting sluggish with the hard drive making noises and intermittently have the rainbow wheel pop up for extended periods of time. Until one day it freezes completely. I performed a hard shut off with the power button and tried to re-boot. To which nothing happened (after multiple tries). Due to the hard drive making noises I assumed it had crashed and promptly replaced it.

Boot up was fine, reinstalled Osx and it seemed to have fixed the problem. Until Yesterday when it had approx. five "restarts" and I use restarts loosely as it acted as though the power was pulled and then booted up again (did not go through shutdown process). Then it froze again, performed hard shut down which on reboot I had no chime, no screen, yet optic drive spins up with #'s 1,2&3 Led's lighted. Re-seated the ram, tried both ram cards (in each slot together and individually) and spare ram cards with no effect.

This morning I plugged back in and on power up LED's #1,2&3 shine for a split second then whole comp shuts down with only #1 LED on.

Any confirmation that the logic board needs replaced would be great, thank you.

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Replace the power supply not the logic board. Your LEDs say so.

See: iMac Intel 20" 2,44ghz mid 2008 dead Diag led #1 flashes

Added with edit this models diagnostic LEDs information:

LED #1

Indicates that the trickle voltage from the power supply has been detected by the main logic board. This LED will remain ON whenever the iMac is connected to a working AC power source. 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 source 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 (turn on and remain 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 (turn on and remain 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 (turn on and remain 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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That thread says the #1 LED is flashing, mine isn't. Mine has a steady on. Also now when I turned on again #1, #2 and #3 are now on. but again no screen, no chime.


+ Good advice mayer. @Paul, yes that thread is dealing with a blinking LED 1. However, if you read the basic troubleshooting in the answer - that is not limited to a blinking LED 1 - you will see that your LED 2 & 3 briefly flashing on and then only LED 1 remains lit is most likely a power supply issue. The PSU is weak, it can not sustain the current draw necessary for the machine to power on/boot. A short on your motherboard could cause the same symptoms, but is less likely than a faulty PSU. I am not trying to stroke mayer or myself, but between the 2 of us you have over 50 years of professional level computer troubleshooting experience advising you.


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