Lenovo Lenovo Y7000 2019 boot screen, a MATS USB flash drive connected to automatically run, you can get the test results, disassemble the machine, and put the machine on the heating platform; At the same time, prepare a new GDDR6 video memory of SAMSUNG, and the motherboard will feel hot. You can begin to disassemble the video memory, then handle the pads and solder the new video memory.
no booting ble found on the b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, BXT.
Power-on detection standby is 3V 5V, and the point switch is not triggered. Upon inspection, it is found that 3VSUS_PWRGD is pulled low, and the high level of 1.0VSUS_PWRGD is required first, so that 3VSUS_PWRGD will not be pulled low. After running the line, it is found that there is a disconnection, but the capacitor must be removed to make up for it. Direct flying line, power-on test, perfect lighting machine.
The main board short circuit causes the soft breakdown of PQ5303, which leads to the protection of the charging chip BQ24780, resulting in the non-conduction of the protection isolation circuit.
Dismantle PQ5303, then connect PJ5301 node, turn on the power supply, turn on the power supply, the current instantly rises and jumps, and then connect the screen to test the perfect lighting machine.
After the machine was disassembled, the BIOS was immediately flashed, which was useless. It was found that the EC also had BIOS, and the failure was still the same. Check the en of U1 to open VCC.When measuring 3.3V to ground, the resistance is zero. It is 3.3V Short circuit Current protection.
HP da0r13mb6e1 notebook does not output 3v5v, you can first try to replace the stable Capacitor, and then replace the chip.
Quickly dismantle the machine, first dry the standby 3 / 5V in the figure below, open the control MOSFET and force it on.Measure the standby 3 / 5V VCC OK, then test the standby and reset of EC, and then check the EC reset is low, and hit 3V linear waveform.The fault caused by the 3V line current of change has been eliminated, and then the 3 / 5V is also current of change. First, disconnect the 3 / 5V isolation point, and then turn off the 3 / 5V. Finally, replace the two pairs of MOSFET of 3 / 5V and power on booting up to remove the fault.
Disassemble the screen and find that there is a short circuit in one data pin. Cut off the wiring at the data end of the keyboard interface and fly to WWAN 7 and 9 pins. Installation test, external keyboard can be used, fault repair
Troubleshooting of no power on on Lenovo notebook 320-15isk It was found that the 3V circuit burned PAD, and it was powered on after checking once there was no error, and the current went up all the way;Power off the…
The test found that the startup was slow, and it took 20 seconds to show it. This is usually caused by ME mismatch after changing the south bridge. Brush BIOS first, buy pure ME BIOS, but the programmer does not support QH128AHIG, and replace it with 25L12873F. The boot test sound is normal. Perfect repair of faults.
