Model A1174 with 2 GHz Core Duo or Model A1207 with 2.16 or 2.33 GHz Core 2 Duo

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How to check power supply generated voltage

Current state:

Zero LED lights up when start up attempted. Supply voltage into PSU shows 120V. If I plug a device into USB it doesn't charge.

I lean towards the PSU being defective, however, I'd like to make sure by measuring the outgoing voltage. Anyone knows which pin is supposed to show what voltage?

Thanks a lot.

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What is the last 3 characters of your serial number so we can determine your exact machine?


Sorry, I thought the system would post the device details I entered when setting the question up ...

EMC#: 2118

Ser#: xxxxxxxxVUV

Model#: MA589xx/A


Apple iMac "Core 2 Duo" 2.16 20-Inch Specs

Identifiers: Late 2006 - MA589LL - iMac5,1 - A1207 - 2118


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1 Answer

Chosen Solution

See if this pinout will work for you:

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So if the voltage between between ground and grey wire is not as per the link, the PSU can be considered 100% faulty. Correct?


BTW, visually the PSU looks fine, with no capacitors leaking, nor bulging.


Capacitors are not the only thing that can go bad in a PSU. True they are one of the more common things. PSUs can have all the correct voltages but not be able to handle the current load of powering up. LED 1 runs off a trickle charge and basically says that the system is plugged in and the PSU has power. LED 1 should be lit all the time if the system is plugged into a working outlet of the correct voltage. If you have no LEDs your power supply needs replaced.


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