Have you ever complain your iPhone 6P has no service after dropping and has not been
repaired well for several times and it does not show IMEI when dial *#06#. And
does it make you feel annoy? If you are really facing this situation, now you
can rid it of, because the Vipprog know how to fix it.
After detection, in “about iPhone” are
IMEI, modem firmware, Wi-Fi address, Bluetooth and ICCID, as shown in picture
1-1.
1-1
There are several reasons as follows for no
service.
- there is no baseband (no IMEI and modem firmware).
- iPhone does not read the SIMcard (no ICCID).
- there are some problems in RF circuit.
- If dropped iPhones displays no service, components pseudo soldering or open circuit may cause the problem.
Therefore, we can conclude that no-service
trouble takes place in RF circuit. Use multimeter to measure several
main test points, finding out the diode data of testing point PP3170_RF is
lager than the normal one 0.406. The location of testing point PP3170_RF is
shown in picture 1-2.
1-2
After checking the schematic diagram,
testing point PP3170_RF is the clock signal RFFE1_CLK of RFFE bus input by
baseband CPU, as shown in picture 1-61.
1-3
Checking the PCB circuit diagram
bitmap and we can see RFFE1_CLK’s signal is sent to many chips. The components
connected to RFFE1_CLK are shown in picture 1-4.
1-4
Removing these chips, we find many solder
pads of these chips have dropped off from motherboard. Use repairing
jump wire to connect these pins of dropped solder pads, as shown in
picture 1-5. And then paint green UV Solder Resist and reweld those
chips. Measure the diode data of testing point PP3170_RF and now the data
becomes normal. Assemble motherboard to assembly and power on to enter the
system. IPhone displays IMEI normally when dial*#06#.
1-5
Finally, screen top left corner shows China Unicom
4G network signal after inserting SIM card and dialing 10010 to test, the
conversation is normal. The iPhone 6 plus is back to normal work.
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