Huawei nova5i Telecom has 2G mobile phone no serviecs repair

Huawei nova5i Telecom has 2G mobile phone no serviecs repair

Machine model: Huawei nova5i
Fault phenomenon: the customer described that there was no signal in normal use, and 2G mobile no serviecs was available in the test Telecom after startup.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 1.

Fault analysis: the chip Inveracious Soldering should be considered first in normal use.
Maintenance process: manual search for operators is normal.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 2.

It indicates that IF works normally, b39 and B41 Related circuit fly off ANT in mobile HB band.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 3.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 4.

Power on test signal comes out, indicating that IF and noise reducer work normally.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 5.

Because this 5I motherboard power amplifier IC is divided into two chips, so it is changed to refer to the Boardview and schematic of nova5i pro. The b38 band back-end passes through a filter, and it directly flies ANT at the back end of the filter.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 6.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 7.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair figure 8.

Start up test signal and call are normal, return to Boardview, filter back-end directly through ANT Switch.VCC was normal.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 9.

Here is the 4V Vbat VCC, directly processing on the line, re install ANT Switch.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 10.

Maintenance results:
Boot test, perfect repair.At this point, Huawei nova5i Telecom has 2G mobile phone no serviecs fault repair.

Huawei nova5i Telecom has 2G mobile phone no serviecs repair Figure 11.