If your cellular data is running out, but
your wifi can not be turned on and the Wi-Fi MAC address can be found in “about
iPhone”. In this time, you will know how depressed you are and maybe your wonderful
day will be ruined. So, how can we fix it? Vipprog can help you.
First teardown iPhone and then measure the
diode data of Wi-Fi chip and PCIE bus communicating through CPU. The test
point of PCIE bus is on the coupling capacitance that is on the right of U1501, as shown in picture 1-1.
1-1
The Wi-Fi chip cannot be removed when the
diode data of PCIE bus is being tested. Otherwise, the diode data to Wi-Fi can
be infinite. The circuits between Wi-Fi solder pad and the 6 capacitances often
disconnect. If that happens, measure the ends of capacitance. The normal diode
data is about 350 on one end and 500 on the other end.
If the iPhone diode data of the 6 capacitances is normal, then remove the Wi-Fi chip to
measure the diode data of every pin of solder pad. If all the data is normal,
first use a normal Wi-Fi chip to replace the old one and turn on iPhone to
test. If the trouble is the still the same, it is caused by unqualified Wi-Fi
working condition.
After checking the function diagram, we
find that the voltage of Wi-Fi clock is not measured. Remove the Wi-Fi and then
measure the clock, there is not 0.9V voltage. The frequency of the Wi-Fi clock
is 32.768kHz, which is made by the Y1200 crystal oscillator. Then Y1200 crystal
oscillator transmits it to power chip .
Power chip transmits it to Wi-Fi chip. Considering the iPhone is dropped, the
crystal oscillator may be broken because it is not anti-shock. Replace the old
Y1200 crystal oscillator. The Y1200 material object is shown in picture 1-2.
1-2
After the replacement, turn on iPhone and
test. Wi-Fi switch can be turned on normally and Wi-Fi signal becomes normal.
The trouble is removed. You can continue to enjoy your wonderful day.
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