Need iMac power supply voltage pinout. Short fan spin then dies

Hi guys,

I’m working on the 2011 27” imac and it gets no power.

• I only get Diagnostic LED #1 on
• When I press the power button, I get momentary fan spin then it stops
• I don’t know what the power supply pin voltages are supposed to be, but out of the 14 or so pin points, I only get a measurement from TWO : 12v and 3.9V

The customer has also reflowed this unit due to the GPU problem, but would the GPU prevent the machine from getting boot power?

Hoping someone can provide the power supply pinout voltages so I can see if it’s logic board vs PSU. Thanks!