[Machine Model]: ACER EC-471 [Board Number]: DAZQSAMB6F [Chip Set]: 6 Series PCH+N Card [Fault Phenomenon]: Water inlet causes multiple faults [Repair Process]: The master handed over a water inlet machine, which was very short.

[Machine Model]: ACER EC-471

[Board Number]: DAZQSAMB6F

[Chip Set]: 6 Series PCH+N Card

[Fault Phenomenon]: Water inlet causes multiple faults

[Repair Process]:

Master handed over a water inlet machine, which was very short. I observed the board and found that there were several water inlet parts, which were cleaned up by the master. I removed several capacitors of the upper tube. I picked up the multimeter and the upper tube to the ground resistance value, and the beep sounded, which seemed to be a short circuit. Considering that there is no isolation point in Quanda , it is difficult to check, there is only one way to burn the machine method, limit the current to 0.5A, start burning, touch it with your hands, huh? Not getting hot? Don't believe it. Go 1A and touch it! It's burned to death, unplug the power immediately.

After finding the hot capacitor and killing it, the resistance value is normal, and then try to power on. Oh yeah, there is no short circuit, there is a common point, 3V and 5V standby, power on, I thought it was repaired, but I never expected that press the switch current indicator to run above 0.3A and then dropped again, OK! A new fault came again, the power was cut off. Looking at the water inlet area that the master cleaned, I found that the foot position of the CPU power supply chip was corroded. After processing it, I found that the small component near pin 37 of the CPU power supply chip was missing. According to the board marking number and looking at the drawings, I found that the component was a 10K resistor. I saw that the 10K resistor on the board was missing. OK! The master washed the brush and took the resistor away, found the 10K resistor and installed it, carefully dealing with the solder pads that were dropped. It's great to power on. The current indicator light started running around, the power was cut off, the screen was connected, and it was lit, but it was not repaired. What's going on? It's powered down again when it's on, and it can't be turned on again. Alas, there's a new fault.

The moment I pressed the switch, the ammeter light flashed. I thought, was it a short circuit? It shouldn't be, power outage, and the common point resistance value is normal. When powering on, it measured the voltage of the common point. It was found that the 19V voltage began to jump. When pressing the switch, it triggered and then dropped the power. There was no way. First, deal with the abnormal voltage of the common point. First, it was suspected that the CPU power supply chip was damaged. For the sake of insurance, the power supply chip and the upper tube were removed. When powering on, the voltage of the common point was still jumped. It seems that it has nothing to do with CPU power supply, and only the protection isolation circuit can be traced.

came to the protection isolation circuit and found an abnormality. The adapter output voltage did not jump, but the common point voltage jumped, which decided to fix this problem. Xiaobai may not understand the process of forming a common point. I will send a picture first and analyze it. Needless to say, the process of

has an explanation.

I thought the PQ1 composite three-stage tube was damaged. After being removed, the voltage at the common point will no longer jump, but it still doesn't trigger. It seems that you must install this. Find the board material board produced by Quanda OEM, remove it and install it on, power on, haha, the common point will no longer jump, but if you are slapped in the face, you will lose power when you press the switch again. It won't be that the voltage at the common point has jumped again! Once the measurement is made, the change is changed again, and the PQ1 compound three-level tube was killed wrong, and continue.

As I looked at it, I found that there was corrosion near the battery isolation tube PQ31. Is it related to this? Power-on voltage.

As expected, this PR28 resistor was opened, and the 33K resistor was found and installed.

After changing, the common point no longer jumps. Press the switch a few more times, and it will still light up perfectly and no longer lose power.

Summary: Before processing water inlet, it is best to take a picture first, so as not to find that the components are missing after washing.

Author of this article: Xunwei ID: (Mu Tou loves to eat lychees).

Computer Maintenance Official Account: weixiuhao123

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