iMac Intel 27" EMC 2309 (Late 2009, Core 2 Duo 3.06 or 3.33 GHz) ID iMac10,1, EMC 2374 (Late 2009, Core i5 2.66 GHz or Core i7 2.8 GHz) ID iMac11,1

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No Ethernet or Airport. Does not startup shut down properly

I have a Late 2009 iMac 27" 3.06 GHz Intel Core 2 Duo. Model Number: MB952LL/A

Ethernet & Airport stopped working. It does not start up or shut down properly.

I ran the Apple Hardware Test, it stopped during the "Logic Board" portion of the Test.

The Error Message I got during the "Logic Board" Portion of the test is:


MOT = Fan Motor

HDD = Hard Drive

I know part of the Error Reports Hard Drive ( HDD-1211), but the iMac runs & does everything perfectly when it is on.

I talked with a Authorized Apple Service Center & the Tech says "It looks like a Fan &/or Sensor Failure on Logic Board. He says if it's Sensor Failure on Logic Board, then I would need a new Logic Board. I'm obviously not going to put $700. into a 2009 iMac & Replace the Logic Board. Does this sound right?

Can anyone help? Thanks in advance.


I thought you might say that. That is what I thought. Logic Board, but as far as Lightning hitting it. I had no idea that was the reason. As far as the electrical part of your answer I have no idea what that means. I know nothing about electricity & wiring.

Answered! View the answer I have this problem too

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Thats OK, your electrician does! Just tell him to replace or add a breaker with a surge suppressing unit. As to the buildings ground: just tell them some of your electronics was damaged by lighting or a surge, and you were told to have the buildings grounding checked and repaired.


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2 Answers

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Give this app a try here: Temperature Gauge Pro. Lets see what it tells you about the fans. Post a snapshot of the results so we can see.

To rule out your HD you may want to setup an external bootable drive. Then booting up under it run Drive Utility on your internal disk repair permissions and the disk (you may need to run them a few times to clear all of the errors).

You also make note of having network issues here. Can you describe what is happening. I find it odd both the wired & wireless services would both go from a hardware perspective. It's possible you have a corrupted OS so using the external drive as your boot up you should see if the both Ethernet & WiFi services are now working.

Did you have a you're system pugged into either a UPS or surge suppressor? Did you encounter a lighting storm that might have zapped your system? Again let us know what you discover.


You're at a cross road here:

The cost of replacing the logic board for this older system or putting your money into a newer system (new or used).

I would recommend getting a newer used system and I would recommend you get an electrician in to put in a whole house surge suppressor into the main breaker panel. I would also recommend to make sure your ground services from the outlet/s to the breaker panel are are all good and the grounding rod/s are in good shape and the connection back to the panel are correctly connected.

I suspect the spike came in though your Ethernet connection burning the network logic out. While you had the system on a UPS the other devices likely are not protected or the lightning jumped to the wiring some how. Lightning does strange things it doesn't need to hit you directly from the sky it can come in though the building from the ground!

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No UPS currently. It was on a UPS. Power here goes in & Out. Florida. Gulf Coast.


How do I post a screen shot? Ok I'll do it Manually.

Here they are:

CPU 38c

GPU Diode 46c

GPU Heatsink 45c

LCD Monitor Proximity 37c

Ambient 28c

Northbridge Heatsink 65c

Optical Drive Proximity 40c

DC in Proximity 50c

Power Supply Heatsink 58c

Power Supply Heatsink 46c

Power Supply Proximity 48c


Some of the sensors are running warm given the fact you don't have a load.


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I have tried booting from another drive with a Fresh Install of Yosemite. Same problems. I would put money on it that my Hard Drive is fine.I know how a PC or Mac behaves when the Hard Drive is going bad. Everything works wonderfully except Networking, Startup & Shut Down. I will download Temperature Gauge Pro & Post my findings in a bit. Look for it. Thanks for your help.

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IF the problems are still present after you have booted up under the external drive. Review this Apple T/N to double check how: Startup key combinations for Mac. Then you have to think how you want to go forward here. As it sounds like your system did get damaged from a power surge.


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Dino Orlando will be eternally grateful.
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