IPhone SE Repair  

Detailed instructions for diagnosis and repair of the phone

Instructions for the diagnosis and repair of iPhone SE, the failure “It will not charge and will not turn on”

Diagnostics

iPhone SE rarely gets into repair.

And so we were lucky! The customer brought his phone with a malfunction “the phone turned off on charging”.

The device did not respond to the connection of the charger and also did not respond to the connection to the PC.

The iPhone SE repair was carried out during the BGA soldering courses.

Diagnosis was carried out in the following sequence:

  • Connect your phone to a USB tester and check for current consumption.
  • The diagnostic block did not show any consumption, the ammeter showed 0.
  • The next operation is to connect the iPhone to the PC.
  • The phone is not detected by the computer and is not turned on accordingly.
  • Then we lifted the display module and connected the original obviously serviceable charged
  • battery.
  • The phone also does not turn on.
  • Measuring the voltage of the client battery, we find out that the battery is working.
  • The multimeter in the mode of measuring the DC voltage showed a value of 3.8 Volts.
  • We conclude that the phone was brought to repair with a serviceable battery.
  • Check the serviceability of the charging dock port system ribbon cable. To do this, we measure the voltage with a multimeter for the presence of 5 Volts.
  • The ribbon cable was serviceable.
  • By connecting the iPhone motherboard to the laboratory power supply, we checked the current consumption by briefly pressing the power button. Consumption was 230 mA.Such ammeter values indicate a malfunction of the TRISTAR chip (U4500).

IPhone SE repair

Приступаем к ремонту.

Подготовка платы телефона для дальнейшей диагностики и замены неисправных микросхем.

Для этого «освободили» плату от корпуса и спаяли защитный экран со стороны NAND Flash.

Visual inspection of the board.

Phone repair technicians know that the most important thing in the diagnosis (troubleshooting) is attentiveness.

Therefore, we devote a lot of time to inspecting and conducting measurements.

It is important to pay attention to the presence of damaged components, oxides and traces of soldering, as well as the effects of the presence of water in the phone.

Carefully inspect the J4600 connector on the bottom charge dock port system ribbon cable.

The connector has no mechanical damage.

 

We checked the integrity of the connector soldering with a multimeter in the diode test mode.

The connector is soldered and serviceable.

Then, for further diagnostics, we connected the obviously serviceable bottom charge dock port system ribbon cable to the j4600 connector.

Then we applied power to the board by connecting it to the charger and measured the voltage across the C4503 capacitor.

The voltmeter showed a voltage of 4.3 V, but with a working U4500 chip (TRISTAR), the voltage on this capacitor should be 5.0 volts.

It was decided to replace the U4500 chip.

To do this, we cleaned the compound around the perimeter of the charge control chip.

Then we removed the TRISTAR with a soldering iron.

Why did we use a soldering iron, not a hot air soldering station? We are often asked about this during bga soldering training.

The U4500 is removed with a soldering iron in order to exclude heating of the nearby NAND Flash chip.

Using the PS-900 METCAL, we soldered the chip, having previously applied FLUX PLUS gel to it.

Then prepared the contact pad on the Board, washing the remains of the compound under the chip, using a copper braid width of 1 mm.

For intermediate diagnostics and confirmation that we carry out repairs in the right direction; we connected the board (with TRISTAR removed) to the charger through the bottom charging dock port ribbon cable and charger. And we measured the voltage on the capacitor C4503 with a multimeter.

The voltage in the circuit rose to 5 volts.

This indicates that the charge control chip was malfunctioning.

Then we soldered a new tristar marking 1610A3B by the key, after rolling the chip.

After the board temperature dropped, the remaining flux was washed with a Flux-off circuit board cleaner.

Then we repeated the voltage measurement.

To do this, they again connected the board (with TRISTAR installed) to the charger through the bottom charging dock port ribbon cable.

On the same capacitor C4503, a voltage was measured with a multimeter and a value of 5 Volts was obtained.

Then we installed the board in the case and assembled the iPhone SE.

We connected the phone to a USB tester. The ammeter value was 0.93 A.

The phone is charging. Repair completed.

What tool was used

The following equipment and tools were used to repair the iPhone SE:

  1. Pentalobe screwdriver 0.8
  2. 1.2 mm Phillips screwdriver
  3. Screwdriver for iPhone
  4. Suction cup for lifting the display module
  5. Fluke Multimeter with Ultrathin Probe Kit
  6. Laboratory Power Supply (30 Volt and 5 A)
  7. Set of wires for the LPS
  8. Bgacenter microscope
  9. Induction Soldering Station Metcal PS-900
  10. Hot air soldering station QUICK 713 ESD
  11. Balls for bga soldering 0.2
  12. Gel FluxPlus
  13. Bga Soldering Stencils
  14. Solder Braid
  15. SolderPlus Solder Paste
  16. WU XIN JI Software

Conclusion

The article provides a sequence of diagnostics and repair iPhone SE. Following this instruction, you can restore the iPhone charge circuit yourself.

 

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