Tag Smartphone & Pad Repair Guide

First test whether there is a short circuit on the motherboard, and then look at the current on the single board if there is no problem with the resistance. This current, together with the Dragon 888CPU on Xiaomi 11Pro, must be a problem with the CPU. Remove the CPU and replant the tin.

The customer described that the charging of iPhone 11 crashed, and it could not enter the system after restarting. After checking the restart report, the fault point was found immediately. The specific maintenance process is as follows:

How to break the black screen of Xiaomi 11ultra without turning it on? Teach you a trick to solve it! “Machine model” Xiaomi 11ultra [Fault phenomenon] No boot. [Maintenance process] I received a Xiaomi 11ultra from a customer. The fault…

The customer described that after the iPhone 11 Pro Max fell, a series of failures began to appear, such as the phone was stuck and the handset was abnormal. After preliminary testing, it was determined that the failure was on the motherboard, and the specific maintenance was as follows:

The customer described that the mobile phone stopped turning on after heavy fall. After being overhauled by the master, the CPU was directly locked, and the fault was perfectly repaired.

IPhone XS Max was not turned on, and it was found that there was no baseband after replanting CPU. After adding a new capacitor, the fault was fixed.

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:

After the iPhone XR phone was accidentally dropped, the WiFi could not be opened. The initial judgment was that the phone was hit and the cable was loose. The following is the specific maintenance process:

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: