Address
304 North Cardinal
St. Dorchester Center, MA 02124

Work Hours
Monday to Friday: 7AM - 7PM
Weekend: 10AM - 5PM

zll

zll

  • Joined: 2021-11-01
  • Articles: 531

Redmi K40 does not turn on, find the fault and fix it easily!

IMG_257
After taking out the mainboard and measuring that there is no obvious short circuit, power on it with a regulated power supply, and the current is triggered to jump at 100mA. This current power supply has obviously worked, and the current is cyclic jumping back and forth, and the jumping range is not large. Therefore, it is judged that it is a fault of CPU virtual welding. The specific maintenance process is as follows:

Huawei enjoys 10plus without charging

IMG_257
After power failure, the resistance of L2501 is measured, and it is found that the front resistance is 380, but the back resistance is only 290. We can measure the front and back ends on C2502 and C2506. Does this seem to be inductance damage? The specific maintenance process is as follows: