Xiaoxin NM-D231notebookDon’t turn it on

Xiaoxin NM-D231notebookDon’t turn it on

Plate number NM-D231 XiaoxinnotebookThis machine is equipped with a unique display, but it won’t turn on or charge due to a fault brought by a colleague. When it is plugged into the C port power supply, it is found that it doesn’t boost the voltage. It doesn’t even have 5V directly, so it is quoted at 300, which is too expensive. The reason will be mentioned later. It is said that it is repaired. Chaxin Manufacturing can’t find the plate number NM-D231, which is made by Xin.blueprintLooking for HS450, there is a set of drawing points. First, repair the C port without boosting, and the C port does not have 5V, which is only about 0.8, indicating that the chip communicating with the C port has a short circuit.

First U30 was removed, and TPS65594AD chip was ordered, so the motherboard was thrown aside, and there was no through board to measure the resistance of major power supply inductors, so other motherboards were repaired first. The next day, when the chip arrived, the chip was installed, but the voltage was still not boosted. The difference was that 5V had stabilized, and when the conditions were checked.

It was found that+5DX _ Walkport was zero to the ground, so the resistance of the whole board was measured, and everything else was normal, except that the standby inductor of 5V was short-circuited, and the back-end was short-circuited by disconnecting the inductor, and the reason for not boosting the voltage was also found. U30 would check the current at the front and back ends of the standby inductor of 5V, first eliminate the short-circuit, and then the tragedy of machine burning came, and the core power supply chip, two driving chips and main memory power supply chip of the graphics card were all burnt out. In order to see if there are any other places burned out, a 20V power supply was given to the current-detecting resistor at the front end of the charging chip with a decoy, and it flew to the ground. It was found that the standby current was more than 100 MA. The measured 5V standby was not generated, and the 3.3V standby was generated. The 5V standby chip was burned with an unprecedented SYV337C (beginning with screen printing CHG), and this was not found on the board. Only the main memory power supply chip was found on the board, so it was replaced first. Others continue to order chips, which cost more than 170 yuan for two times, and they are still relatively cheap. After all the chips are replaced, the C port can be boosted, but when the standby current rises to 20V, it is 93MA, which is obviously larger, but it can be turned on and off normally by pressing the switch, and the current is stuck at around 0.48, which obviously lacks voltage. The power supply is measured by the through board, and only the CPU core power supply can’t measure the voltage, so brush it first for insurance.HS450-NM-D231 Original BIOS- Xunwei. com-Maintenance Forum (chinafix.com)The original BIOS of, after being powered on again, was still the original current, and its conditions were directly checked. This startup came from EC all the way, and all the way was directly connected by ALL_SYS_PWRGD_PMIC. When I was tired, I didn’t check the back source, or my younger brother said to help me refer to it, and checked the source, which was sent by U20, to check its conditions.

Go up and check its source

I have to change the chip again. I feel dizzy. I don’t want to change it. It was once said during the captain’s lecture that these two power supplies can be directly supplied by 1.05V V. This is also a legacy of 5V standby short circuit. After the direct connection, the current has already produced the core power supply. Install the test light machine diagram.

There is also a C-port PD protocol program in the middle.HS450_NM_D231_SVT REV1.0 U49- Xunwei. com-Maintenance Forum (chinafix.com)This program is normal. After brushing the C port, the standby current is stable at about 50MA, and the money is not much, but the experience is priceless.

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