ASUS M2V-VM CPU power supply over current maintenance
Motherboard brand:ASUS
Board Type:M2V-VM
Symptom:CPUPower supply over-current protection, the very non-voltage of control of control voltage12V
Maintenance process:First testCPUNo abnormal supply pipe resistance, look at the powerICFound near the small resistance problems, measured with an oscilloscopeCPUPower has not found an instant pulse waveform. Then removedCPUSupply all the top tube.
Power measurementCPUWaveform of control pad on the pole,In addition to the phase control found in the middle of a waveform other than a very non-normal two-phase waveforms.
Installed on the other tube two-phase power supply to bootCPUNormal power supply, motherboard smooth running code.
Determine which driver is the intermediate phaseICDamage, leading to abnormal feedback circuit, causing powerICOvercurrent protection. Since no such hand driveICReplacement, we can only remove the middle of this phase toCPUTo two phase power supply. Charles PowerICData found that if there is a phase when not necessary toPWMSet foot high Caixing.
Translated means:
Each drivePWMOutput channels.These pins are connected toMOSFETDrivePWMInput. The system uses2Channels, connectingPWM3High.
Because the powerICThePWMFeet and driveIC 2Pin is directly connected, so long as the driverIC2Pin is set high on it, I passed a5KThe resistance of the driverIC 2FeetPWMINSignal is pulled5VPower top, so that played a role in limiting protection, whilePWMAlso set a foot high.
After plug in the power of memory to change the boot normally.
Into the system is running3DTests are normal.
PS: For the two-phase CPU power when the phase change is based on the best description of the above PDF chips that do not have the phase set to high or low.
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