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iPhone 6 Plus RFFE bus disconnection causes no signal repair
Machine model: iPhone 6 Plus
Malfunction: No signal from the plug-in mobile phone, *#06# without IMEI.
Fault analysis: Any chip on the RFFE bus that is damaged or not working properly will cause *#06# no IMEI.
Maintenance process: observing the motherboard under the microscope, the last family basically moved the chip on the RFFE bus, and Baseband also did it.
iPhone 6 Plus RFFE bus disconnection causes no signal repair Figure 1.
Re-install Baseband CPU, the fault is still the same, and there is no shortcut. Check the conditions honestly! It is normal to measure the ground value of RFFE bus more than 400.
iPhone 6 Plus RFFE bus disconnection causes no signal repair Figure 2.
Test that RFFE bus 1.8 V VCC is normal.
iPhone 6 Plus RFFE bus disconnection causes no signal repair Figure 3.
It seems that we can only tear down all the chips that we made last time, and try to replace them again. When removing the U_MBPAD IF power amplifier, it was found that the pad break off was abnormal, and the dropped solder joints were repaired.
iPhone 6 Plus RFFE bus disconnection causes no signal repair Figure 4.
Replace the removed chip, boot it into the system for testing, and enter #*06#IMEI on the dial surface, and the maintenance is over.
iPhone 6 Plus RFFE bus disconnection causes no signal repair Figure 5.
