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모델 A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 또는 2.8 GHz Core i7 프로세서

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iMac 21.5" EMC 2428 doesn't turn on, no fans. Only 1st LED.

My iMac doesn't turn on.

On the logic board is only the first 1 Diagnostic LED turned on. No chime, no fans, no hdd. The power Button is okey.

What i find is:

The 4st PIN on power supply output connector shows 12,05V

The 6st PIN on power supply output connector shows 4,95V

The 1st PIN of J600 shows 12,05V

The PIN 2 and PIN 3 shows 0 - 0,2V

PIN 4 of power supply output connector is railed to PIN 2 and 3 of J600 but they doesn't have 12,05V

It is correct? Or should they have also 12,05V?

Is the power supply fail or maybe the cables from power supply to logic board?

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Wow! I'm impressed! Not many people can spit out these numbers and schematics this readily.

kamilerdmanski pin 2 and 3 should have 12V as well

@Oldturkey03

Also in off or standby-Mode ?

Do yo come from Germany?

Can you write me an email? But I unterstand it right other? Pin 4 of power supply are connected directly to pin 2 and 3 of j600?

Do I understand it right? PP12V_G3H generated PP12V_S0? Which transistor is responsible for this? Through PP12V_G3H flows 12.05V. What does PM_SLP_S3 have to do with it? Can someone tell me which measurements I have to perform?

Image of PM_SLP_S3 is updated in the Question

Nobody can help me???

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I checked some rails:

PP3V3_S5_REG = 3.3V OK!

PP3V42_G3H_REG = 3.4 V OK!

PP12V_S5 = 12.04V OK!

'''PP5V_S3_REG = 0.1 V NOT OK!

'''

'''PP5V_S3_REG is shorted to the GRD.

'''

What could it be?

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