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ASUS S5D does not boot (0CPU power supply tube breakdown)
“Machine model” ASUS S5DASUS S5D
[Fault phenomenon] No boot.
[Maintenance process] I received a machine sent by a customer for repair, the model is ASUS S5D, and the plate number is G531GW. The fault is that it does not start.
Asus S5D does not power on Figure 1
After receiving the machine, remove the motherboard and measure it. If it is found that the common point is short-circuited, just burn the machine directly. If you burn the machine with 0.8V, you can find the problem point with infrared light. If you burn the machine, you will find that the CPU is hot.
Asus S5D does not power on. Figure 2
The voltage of 0.8V will not burn the CPU. We speculate that the power supply MOS tubes of the CPU are broken down, so the power supply MOS tubes of the CPU are directly removed one by one until they are not short-circuited. When the third tube is removed, it is found that the resistance of the common point has recovered by more than 400, and then the two ends of the tube DS are measured and found to have been broken down. It seems that the common point caused by this MOS damage is big and short.
Asus S5D does not power on Figure 3
Asus S5D does not power on Figure 4
Remove a MOS of the same model from the material board and replace it. After measuring that the common point resistance is normal and there is no other short-circuit inductance, power it on directly. At this time, the screen can be lit. In order to prevent this MOS from being broken down again, we found a replacement MOS tube, chose a MOS tube with higher withstand voltage and current, and added a section of heat dissipation copper tube to the MOS tube, so it should not be easily broken down again.
Asus S5D does not power on. Figure 5
[Maintenance result] After the machine is installed, the functions of testing sound, network, recording and playing video are all normal, the frame rate of the baking machine is stable for half an hour, and the fault is perfectly repaired. The maintenance is over.
