Mine card P106 short circuit repair

Mine card P106 short circuit repair

Mine card P106 was short circuited. Because the 5V feedback resistor was knocked off, the feedback was abnormal. Then the 5V chip generated 12V, which damaged the core power supply composite tube and pex power supply chip. The chip fault was repaired.

Machine model: mine card P106

Fault phenomenon: short circuit

Maintenance process: the resistance of the external power supply measured by the machine is normal, and the card is not recognized when the machine is powered on, The current of adjustable power supply is only 0.19V.

Mine card P106 short circuit repair Figure 1.

The current is obviously abnormal, indicating that there must be power supply for this card. Then, after disassembling the video card, measure the ground resistance of each power supply, and find that the ground resistance of five volts is low.

Mine card P106 short circuit repair Figure 2.

When encountering this kind of short circuit, the machine was burnt directly, and a two V voltage was clamped, then the problem came out.

Mine card P106 short circuit repair Figure 3.

It was found that a core powered composite tube was short circuited.

Mine card P106 short circuit repair Figure 4.

Remove the composite pipe, and the 5V resistance will return to normal.

Mine card P106 short circuit repair Figure 5.

At this time, I didn’t repair this composite tube. I’m going to power it on first to check if 5V is abnormal. If it is normal, I will repair this composite tube.

It turned out that there was a problem at this time. Once the power was turned on, it was found that there was a short circuit again. Then I used thermal imaging to burn the machine and found that another composite tube was also burned. At this time, I suspected that there was a problem with the 5V, but because it is short circuited,

Therefore, the short circuit can only be eliminated first, and the other two composite pipes can also be removed together. After the other two composite pipes were disassembled, the measured 5V to ground value was normal, and I was powered on again, and then the short circuit occurred again.

I had no choice but to burn the machine again. At this time, I found that the chip powered by PEX was broken. After this operation, there was a great loss. I had no choice but to continue to repair.

After the chip powered by PEX was removed, the 5V was measured again and found to be normal. At this time, it was observed that except for the core power supply chip, all the other chips on the motherboard were basically removed. At this time, the power could only be applied once again.

Finally, it was found that the five volt voltage was changed to 12 volts, which led to the burning of so many composite tubes and chips in front. After some searching, it was found that the 5V feedback resistor was knocked off, which caused the feedback problem, but the chip was not protected. Finally, after the two feedback resistors are added, the 5V voltage is normal.

Finally, three core powered composite tubes and one PEX powered chip are added. The maintenance of this card is over here