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Old 04-27-2018, 03:47 PM   #3
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Join Date: Jan 2016
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Default Re: Vcore leak/spike at MSI P4M900M2 motherboard

The waveform shown on the oscilloscope is typically measured between the high-side and low-side MOSFET, before the inductor. VCore must be measured after the inductor (marked R25 on the picture), or across the output filter capacitors.
The waveform is indeed spikes of 12V. The MOSFETs switches on and off to output 12V then 0V. The inductor and the capacitors filter the signal to get a linear voltage, average of the previous waveform which should be 1.2V to 1.4V. This is the actual VCore sent to the CPU.
If VCore is lower than 1.5V (it should be) and the CPU is overheating, something is wrong with either the CPU (it should be replaced) or its cooling system, ie. not making good contact with the heatsink or bad thermal coupling (bad thermal paste).
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Last edited by piernov; 04-27-2018 at 03:49 PM..
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