HUAWEI P30 Kein Boot Problem Reparatur

In this article， we will share some HUAWEI P30 no boot issue repair cases for your reference.

Case 1.

Defect phenomenon

phone cannot startup

Fehlersuche

Firstly, change another set of phone parts to test, still cannot startup. The issue could be confirmed is from the motherboard.

Then take out the motherboard and check the cosmetics, everything looks fine. After that, connect the motherboard and trigger to check the current value of the boot process, it dropped when reach 200mA. Based on the boot sequence check the below voltage values

  Voltage Name

  Normal Value

  Measured Value

  VOUT37_1V2

  1.2V

  0V

0V means there should be some shortage on this voltage relative rails.

As we can see from the schematic, the VOUT37_1V2 is sent out from the U1000 to U300

Apply a 1.3V voltage on the VOUT37_1V2 rail, then check the motherboard under the thermal camera, find the U300 is extremely hot. Remove the U300 and check the VOUT37_1V2 again, there is no short.

Replace a new U300 chip then assemble to test, all the functions are OK.

Case 2.

Defect phenomenon

Press the power button cannot startup

Fehlersuche

Firstly, change another set of phone parts to test, the phone cannot be booted, so the issue comes from the motherboard. 

Then take out the motherboard and check the cosmetics under the microscope, there are no burning components, no mold, no deformation… 

Then check the current with the DC power supply, try to trigger the boot process, and check the current.  It keeps jumping between 0-200mA. Measure the below 3 sets of voltage values

•  TP3004(USB_DM_CON)
•  T601.3（USB_DM）
•  T601.4（SOC_USB_DM）

Normally, should be around 0.61V. But the measured result is 0.23V only. Check the schematic, the 3 voltages are come from U300

So still there is a high chance, no boot issue is caused by the U300 damage.

Replace it with a new one then test, the phone can be booted normally.

From the above 2 cases we can see, many start-up issues and functional failures might be caused by the U300.

Case 3.

Defect phenomenon

Cannot startup

Fehlersuche

The motherboard is clean, check carefully under the microscope, no mold, corrosive, parts missing or deformation, etc.

Connect with the DC power supply machine and try to trigger the boot process, the current keeps jumping between 8-10mA, which is a very low value and quite abnormal.

Based on the repair experience, check the U1000 signal rails first.

After measuring, find the VBAT_SYS shorted to the ground. Then apply power on the VBAT_SYS rail and inspect under the thermal camera, find the C1113 get very hot and (looks extremely bright under the Wärmebildkamera )

So remove C1113 first, then we find the short is gone.

After that, replace a new C1113 with the same specification. Test, all the functions are OK.

Special Coupon Code for you read to the end:   ILoveRepair (Can be used for all courses)

Gehe zu Android-Handy-Reparaturkurs to learn more.