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Model A1418 / Late 2013 / 2.7 & 2.9 GHz Core i5 or 3.1 GHz Core i7 Processor

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iMac A1418 late 2013 dead Power Supply / repair possible?

Hi all,

today I took a known good power supply of the above mentioned iMac A1418 (late 2013) and put it in another iMac (same model) so I could test its functionality.

Well, as soon as I plugged in the power cord to this iMac I heard a noisy sound (bang) and the main fuse of the domestic electricity circuit got kicked out. To be honest I have no idea where this came from as I didn't even pushed the power button to start up the iMac.

There is obvious damage at the PSU as you can see in the pictures. I switched the PSU to my own iMac again and none of the status LEDs lights up (no fuse gets kicked either).

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By reinstalling the PSU to the testing iMac again, same thing happened.

How likely would a shorted power plug of the testing iMac's case be? Does anyone know where to get schematics for this PSU (model APA007 from Acbel Polytech INC.) and is it possible to get it repaired?!

Any help appreciated ;-)

Answer this question I have this problem too

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schematics etc. are not readily available. I am not saying they are not out there, just that I have not found it over the last 5 years. In your case it looks like your bridge rectifier has had a catastrophic failure. remove the heatsink and see if your can make out any details on it. Otherwise the only things to do is a replacement.

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Thanks for your reply. Well, I was afraid that it won't be easy to find the proper schematics. I also found the T5A 250V fuse to be blown, which is located on the upper right hand side of the rectifier (2nd picture). So I will have to replace the fuse anyway. Is it possible to check the rectifier in a reliable way (e.g. measuring the resistance etc.)?

P.S.: I will post the details of the rectifier soon.


Alright, the rectifier is labeled as follows:

GBU806 (GC36).

I am not sure what the GC36 stands for but the rest seems to be 600V 8A.

Just ordered a few fuses and give it a shot. If the replacement of the fuse does not do the trick I am going to replace the rectifier as well. But this will take me a few days I think.


Sounds good. Let us know how it works out.


Okay everything is working fine again. I just replaced the fuse and cleaned the pcb with some alcohol. My suggestion is that there must have been a short somewhere in the other casing/logic board. Anyway I am not a 100% sure as I didn't try again after the replacement. Sorry I was too scared damaging the PSU severely :/


thanks for the hint but it turned out that it was just a mark from the former accident.

Thank you all for your help - highly appreciated!


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There is another scorch mark on the other edge of the board as well that should be investigated. It appears to be under what appears to be tape is located on the component side of the board. I would suspect that this area is the origination of the problem with the bridge rectifier being the victim rather than the cause.

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Basti will be eternally grateful.
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