SMPS Mac Mini

[Radio314]

Hi,

I am trying to take the SMPS of my Mini outside the enclosure (several reasons).

I found that the SMPS has 4 12V and 4 0V lines and in the middle is an Isense pin.

The Isense gives 12 V disconnected and seems to go to 2V connected (from what I've read).

But what does is do? I ask this because my external SMPS goes to 0V on al pins after connecting and the Mini does not react on the power button. No leds either.

I wonder if the extra resistance of the cables is sensed? Is that an explanation? I used thin wire. Perhaps to thin?

Thanx!

 

[nigelwright7557]

On PC power supplies the 3v3 has a feedback wire to sense the 3v3 at the pcb.
This is to adjust for losses in the wires.

 

[Radio314]

Thanks! I was wondering why my Mac Mini did not boot but it turned out that it was not the I sense. I interchanged the 12 V and the 0 V wires and I suspect that I sense saved my Mini by turning the power down

But now everything works.

For those who also have a Mini with internal SMPS, there are 4 12 V wires at the edge and 4 0 V more to the middle. The I sense is the middle wire. I have read that one could leave the I sense disconnected if another 12 V suply is used like a batterie.