Samsung A9100 mobile phone repair without charging

Machine model: Samsung A9100

Fault phenomenon: the mobile phone does not charge.

Maintenance process:

A Samsung A9100, which fell heavily, had no sound after changing the screen for two days. Plug in the charging cable to charge, and the mobile phone cannot be charged.

Disassemble the machine, measure that the battery is only 2.6V, and the regulated power supply directly charges 3.7V There is no problem with the installed test screen, but it is not charged. After cleaning up the tail plug, the fault is still there. The measured tail plug is 5V and has been sent to the charging IC U5005, but the voltage of the step-down inductor is 0, and the fault of the replanting charging IC U5005 is still there.

Samsung A9100 mobile phone maintenance without charging Figure 1

Samsung A9100 mobile phone maintenance without charging Figure 2

Samsung A9100 mobile phone maintenance without charging Figure 3

Remove the charging IC, and one end of the measuring inductor L5002 is disconnected from the bootstrap booster capacitor C5029. Replace one, put it back into the IC, and the test can be charged, but the screen is broken.

Measuring the power supply of 1.8V and 3V is normal, and measuring the resistance of MIPI bus to ground reveals that one group is 156 and 567, and the other four groups are all about 567. First, disassemble the inductor F7010, and the measured resistance values are all around 567. No problem was found in simple measurement. Put the inductor back, and the resistance value is normal. The charging display of the installation test is normal. Troubleshooting, maintenance is over.