CPU power supply circuit fault maintenance method.

1. The correct measurement method for CPU power supply.

Each phase of the oscilloscope measurement should be square wave, frequency should be the same. A multimeter measures the G poles of each phase upper tube and lower tube, and the voltage adds up to about 12V. # the multimeter directly measures the inductance voltage, but the accuracy is low.

2. There is no VCORE maintenance thinking.

# Visual power management chip peripheral whether or not dropped, wrong parts. # check VCC, PVCC. according to power chip pin definition Whether the BOOT pin voltage is 12 V or 5 V is normal. If there is no voltage, check the corresponding pin components and lines, supply pin upper current limiting resistance, BOOT pin capacitor and diode. # check if the power chip EN pin has a high level above IV, and if there is no voltage, run to check the EN signal generation circuit and whether the generating conditions are normal. # check the chip VID pin whether there is a high or low level combination, if the VID signal is not normal, and then measure whether the CPU VCCVID power supply is normal, CPU socket is empty welding, VID signal pull-up power supply is normal, above all normal, can only replace CPU. # when the operating conditions of the power management chip are satisfied, the CPU power supply does not output normally, then replace the power management chip and the driver chip. # if the CPU power supply has not been outputted after replacing the power management chip and the driver chip, look for the same motherboard to compare the CPU power supply circuit, or replace the power management chip peripheral capacitance and resistance.

3, the overhauling of the burning field tube. # replace the damaged upper pipe. # replace the damaged upper tube and drive chip and master chip. # replace the damaged upper tube again, measure the G-to-ground value of the upper tube, and check if the upper tube G pole is broken from the chip; on the small side, replace the field tube and drive chip. # check the current of the main chip to detect whether the foot element device and the circuit are normal.

4. Repair that takes a while to burn the tube or where there is an abnormal (no oscilloscope) on the periphery of the CPU power supply. # measure whether the control pole voltage of the tube on each phase is the same. # measure whether the control pole voltage of the tube under each phase is the same. Different voltages-the group is a faulty phase. Repair the corresponding circuit of this phase. # some motherboards need a real CPU to not ring, so you can find an abnormal CPU to test when servicing.

This article is from Allicdata Electronics Limited.