No network iPhone 5S
4 years ago, one of the frequent repairs was a five-esque “hanging on the search network”. The manual will be useful for those who want to repair 5S on their own. The article describes in detail the sequence of diagnostics and repair of the phone. During the soldering courses, we study network repairs of various iPhone models, from 5S to XR, full day.
Why there is no network on the iPhone 5S
This failure may occur due to the following reasons:
- Phone striker, damage to the soldering between one of the chips responsible for the network and the contact pad.
- Liquid ingress, short circuit:
in the chip itself,
in the modem’s power supply circuits.
- The inaccuracy of fixation of the previous service centers. The screwdriver slips when unscrewing the support screws and damages the modem binding (if the protective screen was previously soldered). When examining the Board, pay attention to this.
- U1_rf binding
- The modem power controller is faulty.
- There is no connection between the modem and the modem power controller (breakage).
Diagnostics iPhone 5S does not catch the network
Diagnostics is performed in the following order:
- The first thing you need to do is dial a combination of numbers and special characters * # 06#. Or use 3uTools.
- Make a call for the test. If the modem is working, the phone should dial 112, even without a SIM card installed.
- During the Express diagnostics, go to settings and check the availability of:
- modem firmware,
- ICCID (sim card number),
4. Carefully examine the motherboard under a microscope. What you should pay attention to:
- Damage to the binding or lack of capacitors, resistors, filters, coils.
- The correct installation of the chips (the key location and distances between the chips).
- Electrochemical corrosion when exposed to a liquid.
- Violation of soldering, “acne” of chips, we determine by the presence of balls on the plates of capacitors.
5. With a multimeter, in the resistance measurement mode, we measure the actual resistances in the power supply circuits of the modem power controller and the U1-RF itself. It is convenient to make measurements on capacitors installed in each circuit using a microscope. If we detect a short circuit in one of the lines, we eliminate the short circuit. Measurements are carried out in:
6. With a multimeter, in the mode of measuring constant voltage, we measure the voltage in the above-mentioned circuits.
7. If all the voltages correspond to the voltages on the serviceable Board, we draw conclusions:
- U2_RF generates all the necessary voltages,
- The soldering of u1_rf ball pins was broken due to the phone falling.
- A Baseband reball is required.
Repair network search iPhone 5S
How to safely solder the modem for the Board and U1_RF itself.
- Soldering the modem cover. On the background, we set 330 degrees Celsius. We warm up the perimeter and raise the protective screen with tweezers or a dental probe.
- Remember that the temperature and air flow, individual parameters when soldering Bga. My station has these parameters, and You will most likely have different numbers.
With a spatula, with a hook attachment, we clean the compound around the perimeter of the modem. The temperature of the hair dryer is already 260 degrees, this is enough to soften the resin. The effort on the shoulder blade is minimal, so as not to damage the mask and textolite.
- Soldering U1_RF. The temperature is set to 340 degrees, the air flow is about 100. After warming up the modem processor a little, we apply FluxPlus around the perimeter. And with a special spatula, we raise the modem.
- Then prepare the contact pad, reball the chip and install it on the Board.
After rolling the modem, make sure that there is no short circuit in THE u1_rf power supply. If you don’t have a call center and still don’t have a network, you can update your phone and save the client’s data. After that, most repairs are made.
Repair network search completed
A circuit Board heater is used to reduce the risk of Nickel break-off. How to solder BB_RF and the CPU using STM 10-6 can be seen in the instructions: iPhone 7 replacement Board.
iPhone 5S no network exclamation mark
Previously, there was an exclamation mark on the smartphone screen for five seconds when there was no network. This symbol is not displayed on the latest versions of iOS. How to repair when the exclamation mark is lit and the phone is in search of the network:
- rolling U6_RF. If rolling the EEPROM did not help, and you have already performed soldering of Electrically Erasable Programmable Read-Only Memory, then most likely the non-volatile memory has been replaced. In other words, it was installed from another phone. In this case, the phone can be returned without repair. The network will not find the device. To identify previously performed by soldering Araki possible lack of compound on it. The chip is covered with polymer resin from the conveyor.
How are chips designated in 5S
|2||U2_RF||The power controller modem|
Phone catches the network
There is no network iPhone 5S-a fault that still bring phones to repair. The instructions provide step-by-step steps during network diagnostics and repairs. And in which circuits it is necessary to measure the voltage drop. The video shows the U1_RF soldering method in detail.