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iMac A1311 EMC2428 NO POWER! HELP!!


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10 replies to this topic

#1 ginmasterjedi

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Posted 07 October 2013 - 12:34 PM

Dear BleepingComputer,

 

I am working on a client's iMac A1311 EMC 2428.  It was brought in because it just shut off and would not power on.  I replaced the power supply, I checked the logic board, saw no overheating damage or any blown capacitors. I am at a loss of what else could be causing this issue.

I tried different power cords, nothing. My only guess...is a bad power button?? Or worst case scenario... the Logic board.

 

Any help is greatly appreciated!

 

thank you!!!!



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#2 ginmasterjedi

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Posted 07 October 2013 - 12:41 PM

I should add: after I replaced the PSU I accidentally touched the back of the PSU while plugged in and it bit me so to speak. so I KNOW the PSU is good Lol.

#3 smax013

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Posted 08 October 2013 - 06:33 AM

I assume you have tried reseting the SMC. In theory, you likely reset it when you replaced the PSU as the the power cable would have been unplugged for more than 15 seconds as part of that process.

#4 tgdetjen

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Posted 08 October 2013 - 06:55 AM

I assume this is an older mac.  Find your Application install disk.  While the mac is shut down, hold down the D key, hit the power button, and insert the DVD.  This will take you to Apple's hardware test.  Select the extended testing.  It will take a little over an hour to complete.  Be patient.  If there is not a hardware issue, the results will display, "No Problems Found."  If there is a hardware issue, copy down the codes and take the mac and the codes to your nearest authorized Apple Repair Center.  Before you do that you might want to call AppleCare.  1-800-MYAPPLE.  They can tell you what the codes mean.



#5 ginmasterjedi

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Posted 08 October 2013 - 07:37 AM

its a 2010 model I believe. there's no disk. and no power to test it, period. I hear the PSU humming but when I press the power button on the back....nothing happens. I called my nearest Mac repair center and they told me " it's the power supply that's bad....bring it in to us..."  which I can't because the iMac is one of my clients'.  so right now I have the whole thing taken apart, the logic board and all and i'm re-checking everything one inch at a time.  my next guess is the logic board is bad. I also notice one of the 4 l.e.ds light up when I plug it in LED501 but nothing else happens. I've done some looking around online and I found some articles talking about what it means but no discussions on how to go about fixing it....



#6 tgdetjen

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Posted 08 October 2013 - 12:15 PM

If you call AppleCare 800-MYAPPLE, they will put you in contact with the Apple Sales Office.  They will send you at no charge the Applications Install DVD for your model and the System Install DVD for your model.  The Applications Install DVD has the hardware test on it.  Put the system back together and run the hardware test.  It will report codes and Apple can tell you what they mean.  The test takes a little over an hour.  Select the extended test.



#7 ginmasterjedi

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Posted 08 October 2013 - 12:31 PM

If you call AppleCare 800-MYAPPLE, they will put you in contact with the Apple Sales Office.  They will send you at no charge the Applications Install DVD for your model and the System Install DVD for your model.  The Applications Install DVD has the hardware test on it.  Put the system back together and run the hardware test.  It will report codes and Apple can tell you what they mean.  The test takes a little over an hour.  Select the extended test.

Ok....I don't think you fully understood. the iMac DOES NOT POWER ON.  How can I run hardware tests when the iMac DOES NOT POWER ON? Period.  Only 1 LED lights up on the Logic Board ( LED501) and nothing else works. It does not turn on. I put everything back together, checked ALL the connections, put in a new PSU and still nothing.  Calling that number you suggested is pointless because the iMac DOES NOT POWER ON.



#8 xz4dxx

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Posted 20 October 2013 - 06:03 PM

OK 2009 iMac service details... :clapping:

 

LED #1 = Power available. - if one LED is lit then the Power Supply is PROBABLY working.

LED #1 + LED #2

If second LED is not visible when power button is pressed:

• Verify power button connection to logic board

• Verify power button functionality

• Verify cable connection between power supply and logic board

• Verify power supply

• Verify logic board

LED #1 + LED #2 + LED #3 = Power available, system is powered on, and video card found.

If third LED is not visible after power on:

• Verify that MXM video card is seated properly

• Verify logic board

LED #1 + LED #2 + LED #3 + LED #4 = Power available, system is powered on, video card found, and internal LCD found.

If fourth LED is not visible after power on:

• Verify cable connections between LCD panel and logic board

• Inspect LCD display cables for cable damage

• Verify external video functionality, and according to result check the following items:

-If external display works then verify/replace LED backlight board

-If external display works then verify/replace LCD panel

-If external display does not work verify/replace logic board

 

I hope this helps a little.



#9 xz4dxx

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Posted 20 October 2013 - 06:05 PM

Oh another warning on the web :-

Be aware that a power supply has protective circuits on the main output voltage line (12VDC). When there is a short circuit in the logic board (or audio board, video card etc), you won't be able to start the computer (LEDS 2/3 remain dark) but you can have the trickle voltage. I was fooled once by this situation, thinking of 'only' a defective PS, but when I pulled out the video card my iMac came back to life !



#10 teknis

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Posted 05 May 2017 - 10:53 AM

I am having this same issue with the same model iMac (EMC: 2428, A1311). The iMac was not powering on at all. The power supply was swapped with a new one. At this point the iMac turned on, but the fan was running VERY loud and none of the USB ports were working, so we couldn't login to the OS. I re-installed the power supply and double checked all cables and connections. The next time I tried turning the iMac on, I got nothing. Wont power on at all now.

 

Did anyone happen to find a solution to this problem?



#11 iMacg3

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Posted 07 May 2017 - 03:45 PM

I am having this same issue with the same model iMac (EMC: 2428, A1311). The iMac was not powering on at all. The power supply was swapped with a new one. At this point the iMac turned on, but the fan was running VERY loud and none of the USB ports were working, so we couldn't login to the OS. I re-installed the power supply and double checked all cables and connections. The next time I tried turning the iMac on, I got nothing. Wont power on at all now.

 

Did anyone happen to find a solution to this problem?

Please start your own topic in the Mac OS forum.

Thank you!


Regards, iMacg3

"Do, or do not. There is no try." - Yoda




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