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Auggie

macrumors 6502
Original poster
Jan 21, 2017
388
108
Got a used Mac 2011 27" and it came damaged in transit due to insufficient packing by seller. He offered a discount and a used gutted case, which I accepted as it still worked fine.

But after swapping innards to the other case, it no longer powers on in any way. Swapped everything back and still no-go.

I checked all connections. I checked continuity with a Fluke multimeter from the power input on the back of the case to the twin-disconnect at the arm pivot and it's fine. Circuit test of power button checked out fine too.

All wiring connections appear to have been made properly, from top to bottom, left to right: VIDEO CARD-video top and bottom connectors; MOTHERBOARD-rt skn, HDD fan, camera/antennas, DP power, int DP, ODD fan, ODD temp, SD card, CPU fan and ambient temperature sensor, power button, mic, and I/O connectors.

On the back of the circuit boards I've got the aforementioned twin-power disconnect, video power connector, the PSU connector, the motherboard connector, the ODD power/SATA connector, and the HDD SATA connector.

I've even done an SMC reset (plugged in the power cord for a few minutes, unplugged it for 10 seconds, replugged it and pressed the power button) for no effect.

I don't know of any connectors I missed, so either the PSU was damaged or the motherboard was damaged.

Any ideas?

In hindsight, I should have taken a complete refund, but I'm passed that now.
 
Well, I guess I have to do this the hard way and put my multimeter to heavy use.

I got a copy of the Apple Technician Guide for this model and will start tracing circuits...
 
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