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Model A1418 / Late 2012 / 2.7 & 2.9 GHz Core i5 or 3.1 GHz Core i7 Processor

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One Beep Tone After Replacing Logic Board

I have a 21.5 inch iMac EMC 2544 (late 2012) that had a bad logic board. Well i replaced the logic board, replaced the old memory from the previous board and now when i try to boot the computer it gives me the one beep after every 5 seconds EFI tone suggesting that there is No RAM installed on the computer. Well there is in fact two sticks of Ram installed. I tried removing the new board again and switching the order of the sticks (both of same brand and memory size, again ill reiterate that the RAM now inside the machine is that of the old logic board that came with the computer.) I cant figure out why it would do this and since there is no boot at all it does not boot into hardware test mode.

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Hi, maybe one bar has gone bad somehow during your upgrade process? Have you checked on it using only one bar at a time?

Are both logic boards of the same kind?

I would suggest entering AHT first, maybe it gives you some hint what could be wrong. It's also a good idea to check on the ram by inserting it into an known good system (if possible).


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No I haven’t. I have tried resetting them but I’ll try that next! Just a pain to get to to just try it out then fails and try again haha.

I can’t get to AHT as if it’s Bad RAM the system doesn’t boot at all. I’m hoping it’s just a bad stick possibly


Yes, its not a very rewarding work, but let's hope it works.

How sure are you anyway about having a fully working replacment logicboard? Did you test it before? Where did you pull it off/ got it from? Maybe it's just another faulty logicboard...

Will you be able to get your hands on a known good ram, just for the sake of testing?

Please keep us posted


Sorry for the very late reply, been super busy and just havent had time to get to the repair again, but i did buy some brand new Crucial RAM (204 pin, etc.) and placed it in the RAM slots and still no dice still get the one beep from the ram being placed in SLOT1, but when i tried to place it in SLOT2 i noticed that it just wouldnt turn on at all. no fan power, no anything. So i reopened the mac and noticed i think that while placing the hard drive back in i may have pinched the power button cable and cant find another power button anywhere.... so now i cant get the mac to power on at all.. so if you have any suggestions for this one as well that would be great haha


Also on top of that i bought the logic board brand new, It wasnt a pick and pull situation, should have been a good board, it says it passed the quality testing (or at least that what the sticker said and we all know what kind of help those stupid stickers are.......) hope this helps some more. Im trying to get as much info out there as possible so please ask as many questions as possible haha.


Well, you can power on the iMac without using the regular powerbutton at the backside. Therefore >carefully< shortcut the two pins on the upper left side of the power supply (where the powerbutton cable usually is plugged in) ->e.g. by using a flathead screwdriver or similar - make sure you aren't touching anything else!). Maybe it's also a good idea to check the voltage of the bios battery.

While starting up the iMac keep an eye onto those four diagnostic LEDs, which are located at the logic board.

As for the condition of the logic board... I would be careful. At the best of my knowledge it is very unlikely someone could sell brand new apple hardware if it is not an apple certified supplier (normally even those are not allowed to sell it for spare parts to private customers)... Just a thought...


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1 beep = No RAM installed/detected

2 beeps = Incompatible RAM type installed (for example, EDO)

3 beeps = No RAM banks passed memory testing

4 beeps = Bad checksum for the remainder of the boot ROM

5 beeps = Bad checksum for the ROM boot block"

If there's an issue with your Mac, it might make one of these tones when it starts up:

One tone, repeating every five seconds: No RAM is installed. If you recently replaced or upgraded your computer's RAM, check to see if it was installed properly. If the issue continues, contact Apple Support.

Three successive tones, then a five-second pause (repeating): RAM doesn't pass a data integrity check. If you recently replaced or upgraded your computer's RAM, check to see if it was installed properly. If the issue continues, contact Apple Support.

One long tone while you hold down the power button: An EFI ROM update is in progress. This applies to Mac computers from before 2012.

Three long tones, three short tones, three long tones: EFI ROM corruption is detected, and your Mac is in EFI ROM recovery mode. Newer computers automatically recover from a corrupted ROM; when this occurs, a progress bar appears on the screen during ROM recovery mode. Don't disturb your Mac while the ROM recovery takes place. When recovery is complete, your Mac restarts.

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I appreciate your comment but as Basti and i have been speaking about above it is the one beep tone and even new memory isnt allowing the boot of the computer. The old RAM that worked fine on the previous board that went bad but the new board was what started this whole RAM issue.


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Dylan Kent sera éternellement reconnaissant.
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