Yesterday, we got a message from our customer, he said his iPhone 6S Plus has no service, even if the phone is restarted, it doesn't work. So, he send the phone to us. After we check it, the phone cannot recognize the SIM card, but it can
search the operator manually. We suspect that this problem was caused by the
launch part.
Disassemble the iPhone by phone opening tools, and carefully take out the motherboard.
Using multimeter to measure the diode data of
PP_1V85_SMPS4, the diode data only have 59, as shown in picture 1. Because
this voltage is supplied to RF IC, so we remove the RF IC.
After we remove the RF IC, we measure it
again; the diode data back to normal. So we replace
the new RF IC on it, we can check it under the microscope, as shown in picture 2.
Now we turn on iPhone, and test it, the
signal is back. However, during the testing process, we found the 3G shows no
signal, when we choose 3G signal, it will be no service, 4G and 2G is normal.
Other signal all is fine except 3G; this
trouble is mostly caused by the UMBPA_RF. After we replace the new UMBPA_RF
with phone rework station, 3G signal is normal.
Finally, test other function on the iPhone
6, all is fine, the repairs are over!
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