iPhone 6 is dead after replacing touch IC
Hi everyone, I run a phone repair business for a few years. Yesterday a customer brought me an iPhone 6 with touch decease (touch is completely dead). I removed and reballed the silver touch IC (U2401), put it back, the touch was back to life. However one line on screen was not responsive. The touch was working on every corner except one line not responding. So I thought the silver touch ic was probably not properly reballed. So I removed it and did the job one more time. This time however, the phone was completely dead. I removed the silver touch ic again to verify there is no short on the chip. I tested the phone again without the silver IC, still dead.
I tested the battery line, didn't find any problem. Voltage is normal. No short on the vcc_main line either. Finally I removed the black touch ic (U2402) to verify there is no short on the black touch ic. I tested the phone without U2402, unfortunately the phone is till dead.
I want to ask, can the phone turn on without the black touch ic (U2402)? I googled it around, someone said the phone can turn on without that chip, someone said it must be there in order for the phone to turn on. So I am a bit confused now. Can anyone confirm that if the U2402 is a must to turn on the phone?
Also can anyone shed light on what to do next? I don't think the CPU is over cooked, I only used low temperature. Many thanks.
Is this a good question?
4 Comments
Does any part heat up when plugged into a charger? Also does a computer recognize it?
by Gigabit87898
No, I didn't notice any parts over heating.
Yes, the phone is recognized by computer and detected by iTunes.
Inpired by your comment, I tried to restore the phone via iTunes. Magically the phone turne on during restore! Although the restore failed (error 40), but at lease it is able to turn on during restore. I will put the two touch ICs back on, then restore it, see how it goes.
Do you think the black touch ic (U2402) is a must to turn on the phone?
by phonestore.uk
I put the black touch ic (u2402) back on, however, the phone still won't turn on. :( I run out of ideas.
The backlight driver ic on the other side is fine. The backlight ic is not shorted or damaged, because the phone can turn on during restore. I also tested the capacitors around the PMIC, the voltage readings are correct (4.2v).
I don't know what else to check. Can anyone help me?
by phonestore.uk
I think over heating while replace touch ic may cause that fault,Even touch ic remove and i check the phone will turn on.
by Akash