iPhone 6 was Released in 2014, September 19.
Even through by now with more than 7 years passed, some iPhone 6 are still in use. And also still with a high repair demands in the market. Here, we gonna share some iPhone 6 repair common faults based on the motherboard chip level.
PP_VDD_MAIN
- C5202_RF
The big capacitor which around the Wi-Fi module
- C1597 / C1552
The two capacitors which very close to CPU chip. And they are also very clost to the edge of the motherboard. It might be the location reason, may easy to get drop/water/ESD damage.
See location of the two components as below (Quoted from Refox Bitmap)
PP1V8_SDRAM
- C1923
- U5411
The upper antenna jumper
The 3V voltage supply for the NAND
- C0634
PP1V8_SDRAM short
- C1214 C1216
As marked in the circle, the two small capacitors are just above the CPU chip.
Specification of these two capacitors can be searched from the schematic
PP1V8 diode value abnormal
- As we can see from the bitmap, PP1V8 related with many chips and components
One common fault is the measured diode value of PP1V8 is 30, and there’s a high chance it’s CPU get shorted.
Where there is short there is current leakage. And in the most cases, it’s caused by below three reasons
- the fingerprint circuit with problem
- the 3V power supply of compass related filter type capacitor with problem
- USB chip itself get damaged
Drop damage common faults
And for the iPhone 6 repair which is caused by drop damage, based on the repair experience, there are some common faults. Let’s have a look, details as below
- Wi-Fi module pin 14 (The reset signal pin) with inner rail broken
This kind of problem can be fixed by jump wire from R5208_RF to C5212_RF / or the test point
The reason for this pin may get damaged easily is obviously. As we can see it’s just at the top edge of the motherboard. When phone dropped, the components around the edge and corners are always easy to get damage.
- The inner rail between CPU and EEPROM get broken
The normal diode value is around 450, abnormal value around 600
For this kind of issue repair, we’ll need to scratch out the CPU then jump wire, which is a kind of expert/ master level handwork repair. Enough repair experience and skills are required!
- The U1 and V1 pin of baseband CPU get damaged
This can caused no IMEI number and no service.
Repair method: teardown the BB CPU chip, then jump wire to the pads around them to fix
(Since BB CPU is also an encrypted chip, think twice before you decide to do the operation)
Some other issue repair experience sharing
- Camera issue – rear camera do not work
There is a high chance it’s caused by the LDO U2301 with problem. We can jump a 3V voltage from NAND or replace the LDO chip to have a try.
- Touch issue – No touch
The Meson U2402 with a higher failure rate, just try to repalce it directly.
(Meson responsible to provide powers for the screen, the load on it is higher than CUMULUS)
- No signal / No service
As we mentioned earlier. After excluding the BB_CPU U1/V1 rail damage, then there’s a high chance signal function failure is caused by the transceiver with problem.
Solution： Try to replace the transceiver chip (U_WTR_RF) with a new one first
- No charging issue
Based on the repair experience, for the charging issue. Failure rate of the related chips:
Charging tube (MOSFET) Q1701 > USB IC (U1700) > Charging IC (U1401)
- Can try to replace the above mentioned chip one by one to have a test.
- For the MOSFET, we can just short it to test first. If issue resolved, remain the short conditon or replace the MOSFET with a new one.
* After that if issue still unresolved, may caused by the small capacitors/ inductors with charging function.
- No display caused by the screw damage
There is also a common issue is caused by screw over crack damage.
So when assemble the phone, please pay more attention and do not lock the screw on the motherboard too tight / do not use the wrong screw.
Above common iPhone 6 repair methods are based on repair experience.
If you want to learn the repair logic systematically, you can visit REWA Academy to have a look. The theory, handwork and repair case lessons could help you a lot in the future repair business.
