Tip & How-To about Apple iPhone Smartphone
Do you feel curious why the iPhone 6 will not be able to display IMEI when dialing "*#06#" after falling down? But have to be aware of is "about phone" can shows it. So, what's wrong with your iPhone? Vipprog answer for you.
First you have to know where the problem is. This kind of trouble is caused by RFFE bus of the baseband that does not work. In most cases of dropped iPhones, the circuit of pin U1 of the baseband CPU is disconnected. The location of pin U1 is shown in picture 1-1.
To solve the problem that dropped iPhone displays no IMEI when dialing *#06#, first remove baseband CPU to check whether the pin U1 comes off from the solder pad. Then measure the iphone diode data of U1, U2, U5 and R5.
After teardown iPhone, remove baseband CPU, we can find pin U1 and pin V1 come off from the solder pad, as shown in picture 1-2. This iPhone shows no IMEI when dialing *#06# because when pin U1 comes off, baseband CPU cannot communicate with peripheral circuit.
Above all scrape the circuit that is connected to the pin U1 and V1 on solder pad, as shown in picture 1-3.
Then plate the welded joints of U1 and V1 with tin and place two enameled jump wire on the solder pad of U1 and V1, as shown in picture 1-4.
At last, paint green UV Solder Resist on them and reassemble baseband CPU. The signal becomes normal after power on, so the trouble is removed. You can normal use the iPhone again.
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