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820-2993 short to the ground

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Dmitry

New member
I have mac mini 820-2993 there are no schematics available, the board is in short. Power supply works. I inspected board carefully and didnt find any bad capacitor or other deformation. Board is not water damaged.
Well at this point I tried simply supply power to the board directly in hopes something get warm.
CPU got warm, then I started picking coils to find out if it is something in between or the CPU, slowly and surely I got all the way to COIL next to CPU. Removing that coil removes short from the board except on CPU side ( I assume cpu side). So I gave it 1v to make sure, and cpu get warm. Did I actually discover short or it is simply low resistance power rail?
My question is did I ruin CPU when connected power to the board and warm up CPU?
I am not sure what alse can I do in this case,could any one suggest troubleshooting ideas that would help?

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dukefawks

Administrator
Was the short on the main bus? If you put more than 3V on the bus of the CPU it is probably dead already.
 
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Dmitry

New member
dukefawks said:
Was the short on the main bus? If you put more than 3V on the bus of the CPU it is probably dead already.
Click to expand...
Yes main bus was short to ground. Connector that get power from power supply was short to the ground. Since I didnt find any broken capacitors I supply 12v to the connector were power supply goes... Did I do it wrong? I am trying to apply my cellphone repair experince to the macbook repairs. How should I have started if main bus is in short?
 
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dukefawks

Administrator
So you applied 12V to the main power bus and the CPU heated up? This indicates a shorted "high side" FET in the CPU power supply and probably will have killed the CPU already.
 
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