Question My turns pc on for split second

Nov 12, 2019
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Changed my motherboard on my PC and power supply
Specs
Intel i3 7100 cpu
Msi 1060 3gb gpu
Msi Z390-a pro
300 watt power supply
It boots without screen signal and without mouse/keyboard turning on if I unplug the 8pin cpu power
. If I plug the cpu power the PC lights/fans start spinning and the PC turns off .
The ez debug led cpu turns on regardless the cable being connected