Last weekend, a customer sent a iphone 6 that is no ringtone and it gets stuck when open the ringtone option system. Vipprog engineer check and fix the issue phone, and give him some suggestions. Lastly, the iphone 6 fix well. Now I will sort out the guide, if you need phone repair tools and guide, you should try vipprogrammer.com and read this article.
A nonlocal customer sent the iPhone. It has no ringtone and it gets stuck when open the ringtone option system with other functions working normally.
1. Press the power button and get into IOS system. Change ringtones and test. There is no sound and it is stuck. It poses the same problem when inserting earphones. Turn it off and remove the motherboard. Observing with eyes, we find that the audio amplifier has been soldered and one of the corners has been damaged, as shown in picture1-1.
2. Find audio amplifier U1601 on circuit diagram and find its pins of power supply and reset, as shown in picture 1-2. Energizing the sole motherboard to measure the power supply and reset of U1601. They are normal.
3. As the working condition is normal, we continue to check the audio amplifier chip bus. Remove the audio amplifier chip and measure the diode data to ground of its I2S2 bus. We find the data of signal AP_TO_CODEC_XSP_I2S2_LRCLK of audio amplifier chip pin F6 is on the low side. Pin F6 is shown in picture 1-3.
4. After referring to circuit diagram, we know that the signal circuit of AP_TO_CODEC_XSP_I2S2_LRCLK connects audio frequency chip U0900 and main CPU U0201, as shown in picture 1-4 and 1-5.
5. Besides, we also find some solder paste near audio frequency chip U0900, as shown in picture 1-6.
6. Tear audio frequency chip U0900 down and measure diode data to ground of signal circuit of AP_TO_CODEC_XSP_I2S2_LRCLK. We find the data recovers to its normal number about over 400. Replace a new audio frequency chip and assemble the motherboard to assembly. Turn on iPhone and get into IOS to test the ringtone function which is now normal.