General discussion

iMAC does not boot, only chimes. Keyboard not responding


I am trying to figure out why an iMAC does not boot properly.

Model ECM 2133
Memory:1GB (only 1 module in one of the 2 available slots).

Everytime I push the power button I only hear the chime sound and that's it.

You can hear the HDD spinning but the screen is always black.

I already did the SMU and PRAM reset and nothing changes.

Keyboard is still unresponsive and the screen is black. Mouse light is responsive.

Any ideas?

I pluged the keyboard on another computer and it works fine.

Sorry if I'm not doing something right but I am a newbie with MAC's


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What sort of iMac is this?

I don't recognize the ECM 2133 designation.

Could you describe it?

Did you buy it new and how long have you had it?

What version of the Mac operating system are you using?


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iMAC does not boot, only chimes. Keyboard not responding

Sorry I meant EMC 2133 iMac (20-inch Mid 2007) Intel Core 2 Duo.

This computer was bought brand new.

I really don't know what OS is has as this computer is from a friend who has had it for approximately 2 years and as I said I cannot see anything on the screen that could help me see a thing.

Unfortunately the warranty already expired.

My friend told me that another person had already disassembled the iMac in hopes to make it work so I don't know if I should do the same and see if there is something wrong that can easily be fixed.

I aleady did an SMC reset and the only thing that happened is that the iMac became a noisy iMac, very very noisy. I unplugged/plugged in back again and the noise came back to normal.

I don't know if the PRAM reset is working as the keyboard seems to be unresponsive.

Mouse light does respond to movements though.

Thanks for your help.

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That iMac

A number of things could be wrong with this machine.

Anything from the graphics card through missing connections to logic board.

Given that they are not the easiest thing in the world to take apart, correctly, and just as finicky to put back together, it would not surprise me if the previous person did more damage while trying to fix it.

That said, what more damage can you do to this none working machine.

By all means, take a look inside. Just a hint, the back does not come off. Everything is done from the front.

Good luck, let us know how it turns out


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Opened tje iMac

Well I just managed to open the iMac but partially.

I took off the screen and unscrewed the front screws and that's it.

There are not much connections unless I go further which I am reluctant to do as all the components seem to be firmly soldered together and I'm not sure if I can put them back again Sad

Any other ideas that not require disassembling the iMac?


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Not really,

the whole thing comes apart without messing with any of the soldered joints.

Try Google for a "Take Apart"


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No videos for iMac

Unfortunately there are no videos or instructions for the iMac on Take It Apart Sad

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Have you tried to turn up the brightness?

Just a thought..

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how do you do that with

a non-working keyboard and no external controls on the iMac?


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There are,
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I don't understand

What you guys mean by "a non-working keyboard and no external controls on the iMac?"

And "Have you tried to turn up the brightness?"

If this is supposed to be a controlled via the keyboard I don't think is possible.

I disassembled a little deeper the iMac but didn't see any loosen wires.

If I go further I run the risk of now knowing how to re-assemble the iMac again Sad

One video from youtube says that the GPU may have been disconnected when the other guy opened the iMac or that the power DC cable could is defective but in order to figure this out I would have to remove almost ALL the components.

Any thoughts?


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I can only address the question that I asked

"a non-working keyboard and no external controls on the iMac?"

I was asking the previous poster how they would turn up the brightness in view of the above.

Did you watch the take apart video?


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I feel your pain

I feel your pain, as I have had to fix 4-5 of the 24" models of that same refresh.

At this point, since you've already opened it up, tell us about the diagnostic LEDs.

There will be four of them, and they will be clearly visible once you've taken off the front bezel (the gray housing. Being very careful, plug the system in and press the power button. Give it a good 30 seconds, and tell us how many of the 4 LEDs are lit.

But I'm afraid that your friend is likely going to need a new iMac in the near future, because there's probably a 90% chance it's a bad logic board from what you've described so far, and based on my own experience with those systems. Getting that repaired out of warranty... Probably be at least $500, and when a new 21.5" iMac starts at about $1200 with a faster CPU, bigger hard drive, better graphics, more RAM, and most importantly, a much better quality display... It's just not economical.

You can also check ebay to see what it'd cost to get a new logic board from someone, but then you have to put it in yourself. It's not really hard, it's just a bit involved keeping track of where all those cables go, and there are a lot of screws to remove. I also find that a T6 Torx screwdriver isn't a very common one for people to have, and I can tell you from experience that the T6 screws in that model will strip at the drop of a hat.

If your friend goes the new system route, tell them to get the AppleCare warranty. Just a SINGLE incident like this will make that pay for itself and then some.

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beeps and no screen

if your system has no video (black screen) and beeps over and over it is possible that the RAM is not installed, or is faulty. have lots of online guides to taking your iMac apart and they are a friendly bunch too.. here is a link to a full teardown

here is one for taking RAM in/out

Keep us posted on your progress

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No beeps

Hello Rich:

The iMac does not beeps over and over. It chimes normally which means it passes the POST.

I think the RAM is just fine.


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from the MID 2007 service manual

What are the diagnostic LED's doing?

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
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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LED location

According to the manual the LED's are on the logic board to the right of the memory slots and above the HDD SATA connector. The SATA connector is a right angle connector so may obscure them a little

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Cannot find LED's

Sorry but I cannot see any LED's.

I am the point where I can see the logic board, HDD, DVD drive, etc.

Apple says there should be a big white arrow where the LED's are but this arrow does not exist.

I cannot easily deattach the screen as it has several connectors that go to the logic board.

Again I have iMac model EMC 2133.


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You don't need to

You don't need to remove the display to see the diagnostic LEDs. If you've removed the bezel, then just be very careful and plug the thing in. You should see at least one green LED turn on at that point. They will be obscured by the SATA cable, so remove that. I unfortunately can't post images from the service manual due to Apple forbidding it, but if you do a Google image search you should be able to find someone's pictures of their iMac. There is no arrow, you probably just got some person on the phone who's new and doesn't know that the big arrows in the images they pull up aren't actually in the systems.

There's a small chance that it's something else, but odds are that it's the logic board. Seems to be a common failing with these systems. The 24" models I repaired all started running VERY hot right before they failed. I let one of them sit for about a half hour, it was still warm to the touch.

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LED location
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Those would be it

Those would be it, and they will turn green depending on different circumstances.

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Seems like the logic board is toasted so I'm screwed
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If you are sure it's the main board
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I'm just saying

I'm just saying that I have personally had some dealings with the company you link to. They actually are located not too far from a warehouse I use for parts delivery. I won't get into any specifics unless asked, but I would avoid using DT&T. They also don't sell just the parts, they're listing what they can get it for from Apple.

I'll just tell a little story, which is true, so they can't complain about it legally.

Needed to repair a MacBook with a bum logic board. Order the part from Apple, FedEx mistakenly delivers it to DT&T instead of my warehouse. I spend a couple of days trying to figure out what happened to this package, and get Apple to get FedEx to put a trace on the package. In the mean time, Apple sends me another logic board, which happens to be DOA. The client at this point is getting quite belligerent because they need the laptop for something or another in a day or two, and what should have been maybe a 1-2 hour repair has turned into a 2-3 day fiasco.

So in an effort to try and get the system repaired quickly, and having had some dealings with DT&T in the past, I give them a call. Ask them if they have the part I need in stock, they say yes, I say great and bring the laptop by.

Well, long story short, the result of the FedEx trace is that the logic board I was waiting on initially was delivered to DT&T. No one there apparently bothered to look at the shipping label and see it wasn't their package. Not that it stopped them from opening it and apparently adding it into their inventory. Then they put the new logic board in, which was my part anyway, and charged us the full $500. And they knew my late boss from way back when, and couldn't be bothered to pick up the phone, or just drive about a mile down the road to drop it off.

You can take from that story what you will, in my opinion however, it suggests many troubling things about the company.

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Thanks for letting us know Jimmy, I will take that into account if I ever need to replace the logic board which is most likely.

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Anyone ordered from the following supplier?
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Sorry wrong link
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No, I've never heard of them, but if you take a look, a logic board for a 20" mid-2007 iMac is about $800.

Apple systems are rarely worth repairing if out of warranty. The cost of parts is just too high. Anything more than a failed hard drive gets to be a significant portion of a new system.

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