Power failure repair of Shengji KN9S motherboard

Shengji KN9S motherboard auto power off,short-circuit r361, rewelding MOSFET, power on, maintenance is finished.

Machine model: Shengji KN9S
Fault phenomenon:auto power off can run code soon after power on
Maintenance process: received a board a few days ago, first put on a full picture.

Power failure repair of Shengji KN9S motherboard Figure 1 .
Test, power on run code, code has not run out on the fall, can not switch.

Power failure repair of Shengji KN9S motherboard Figure 2.
After measuring Switch pin, 5V was normal.The temperature control circuit is in good contact with the CPU.

Power failure repair of Shengji KN9S motherboard Figure 3.

According to the drawing, it is found that Q33 VCC D pole is only 2.3V. If it is pulled up by 3vdual, it should be 3V normally, and VCC is on the low side,

Power failure repair of Shengji KN9S motherboard Figure 4.

Power failure repair of Shengji KN9S motherboard Figure 5.
Measure g pole, found no VCC, remove Q33, measure d pole is still 2.3V, check the circuit found that the destination is bridge and IO, nothing else.short-circuit r361 has 3.3V, there is a problem with the resistance. Originally, I wanted to connect it directly, but I finally found a resistor to connect it. The measurement of VCC has 2.9v, which is barely feasible. Therefore, the MOSFET is soldered again.