ASUS S5D does not boot (0CPU power supply tube breakdown)

ASUS S5D does not boot (0CPU power supply tube breakdown)

ASUS S5D does not turn on the machine, and the motherboard is removed for measurement. If it is found that the common point is short-circuited, the machine can be directly burned. When the machine is burned with 0.8V, the problem point can be found by infrared light, and the CPU is found to be hot. The specific maintenance process is as follows:

“Machine model” ASUS 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 won’t 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 it is found that the two ends of the tube DS have been broken down. It seems that the common point is big and short caused by this MOS damage.

Asus S5D does not power on Figure 3

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 4

[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.