Motherboard model: Gigabyte ga-b250m-d3h motherboard
Fault phenomenon: the main board does not display when it is turned on
Maintenance process:
A gigabyte ga-b250m-d3h motherboard, the fault is that the motherboard does not display when it is turned on.No Short circuit at 12V,switch after direct power on.
The memory of 1.2V VCC is normal.
Gigabyte ga-b250m-d3h motherboard does not display figure 1.
The memory of 2.5V VCC is normal.
Gigabyte ga-b250m-d3h motherboard does not display figure 2.
The bridge VCC 1.0V was normal.
Vccsa VCC was abnormal.
Gigabyte ga-b250m-d3h motherboard does not display figure 4.
Look at the drawing for 358 control, 358 of the third pin for low level.
Trace the en signal from dqc2 field pipe.
Dqc3 field transistor B pole 1.2V is normal.
Gigabyte ga-b250m-d3h motherboard does not display figure 7.
Measure dqc3 field tube C pole 5V, abnormal.
Gigabyte ga-b250m-d3h motherboard does not display figure 8.
The dqc2 field tube was directly removed, but there was still no VCC. It was found that the 2.5level VCC was not generated by measuring the partial voltage resistance.Trace from Io chip,diode value is 0,Capacitor,Short circuit.
After removing Capacitor, the mainboard was repaired.
