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Model A1419 / Late 2013 / 3.2 & 3.4 GHz Core i5 or 3.5 GHz Core i7 Processor, ID iMac14,2

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Anybody know how to test a power AC/EMI filter failure?

Diagnosis LED #1 keeps blinking after I had replaced the Power Supply (PSU)

No chime, no fan activity, no “Electric buzz” on surface, like total dead iMac.

I wonder how do I check the Ground of the AC inlet EMI filter, before I buy a new motherboard.

I checked with multimeter the AC inlet EMI filter cables that suppose to connect to the MB and I see voltage, that mean the positive/live line pass through the AC inlet EMI filter but I don’t know how to check the ground line…

Because from the AC inlet come out a Green cable that is attached to the external surface, and I can’t feel anymore the electric buzz when I touch when it was working normal, always feel like a little buzz.

Could the ground line malfunction cause the LED 1 blinking and do not start at all?

Could be the EMI filter AC inlet be the reason?

I would be happy to find any suggestion before I decide to do something

Ответ на этот вопрос У меня та же проблема

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Lets backup here… Was the system not working from the start? Can you tell us a bit more before you replaced the power supply.

You talk about "Electric Buzz" This sounds like you have a mis-wired outlet Vs a bad power supply. Did you check the outlet first using a outlet tester? Also did you try a different power cord as sometimes they are bad.


Yes, my friend my 27 iMac A1419 it suddenly shut down and never start again, i Opened and the LED 1 Blink all the time when its plug it to the AC LINE. Then i replaced the PSU and i get the same results LED 1 Blinks when i press the button to start blinks faster, when i release blinks like before i press.

The electric buzz its not a shoking electricity, its like when i touch the iMac surface slowly i feel (normally when is working) a little electricity like static electricity once its plug it to the AC line, But now even plug it to the AC line, I cant feel it anymore. The outlet its not the problem. May be the INLET EMI FILTER? And Yes, I tryied different cords in case that was the problem too


If you feel a buzz touching the case thats AC power leakage! Thats not good!

In the winter or very dry climate you can get a slight static electricity zap touching the case, but once your body is at the same voltage potential you shouldn't feel anything more.

Did you friend have a good surge suppressor? Could you have been hit by a lightning strike or get a power surge?


@danj Friend, I was Cleaning my desktop unplug my ssd external with High Sierra, then from that system i select to start from the HDD with Yosemite. ( so i dnt plug it back my SSD external, cuz i want the HDD start)

So then i plug back my Imac A1419 once my desktop was fully cleaned :-) and press the start button. Then I see the Imac start: the apple sign, untill the HDD YOSEMITE pasword screen. The password screen just long 1 second and the computer shut down forever... so was not a electric shock or lightning. The Buzz i talking about is like the old computer cases... like the intel 486 first vertical cases remember? the feeling like you get some buzz or static touching? even when the ground were well connected. Ok that my iMac have been doing untill the "DEAD SHUT DOWN" and now PSU replaced, still No Sign of LIFE even the buzz feeling


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@samuelmgm12 to check your EMI filter use an ohm meter. Measure from one prong of where you connect the power cord (line)to one of the output lines past the EMI filter (load). You should get around 0.4 ohm. Same with the other prongue. Remember that there will have to be continuity. Measure from any of those points to the case of the filter. Your meter will either show a 1 or OL because there should be no continuity (shortcircuit if it does). The green cable is actually the ground wire. You can check the ground the same way. One lead to the prong (line) and the other on green wire should give you a OL on your meter (no continuity). You can check both prongs to ground. Yes, a failed filter will not allow your AC power to pass.

In that case your iMac should not display any LED. LED#1 lighting up means that power is available.

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Thank you i will check and tell you whats going on!


I'm getting 0 ohm across the EMI filter (neuter to neuter, live to live), and about 2.3 Mohm across the poles (neuter to live, live to neuter). Is that healthy?? TA


@Valentino M You really should not get anything across live/neutral. that would indicate a short circuit.


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The power outlet is a straight through wired with the pig-legs wires to the power supply. Each line has a Ferris choke to clamp down the EMI emissions.

Tyco - Power line filter (first order filter)

I haven’t needed to replace the part other than one time when someone bent the ground pin snapping it.

I would use a DVM and with the system turned off and fully assembled and with one lead touching the case and the other touching a good known ground point do you see any AC voltage present?

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Thank you i will set it up and check as you told me, friends. And im gonna tell you what happend


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