Lowyat.NET: Latest topics by Linda Chan

Why iPhone Boot Loop after Screen Replacement?

Linda Chan — Wed, 15 Jun 2016 11:49:34 +0800

It is not unusual for an iPhone to experience problems after a recent repair, such as screen replacement. Boot loops are one of the more common symptoms of a poorly performed iPhone screen replacement. When the iPhone is powered on, the iPhone may either get stuck at the Apple logo or you might get a static blue screen; shortly after which the iPhone reboots and goes into the same cycle again. In either case, the user is unable to access the home screen.

Boot loops are often seen after screen replacement. It is important to identify what causes this problem. During the replacement of the iPhone’s screen, the four screws holding the plate over the screen connectors are replaced. These screws are not all of equal length. If you fail to note which screw goes into which hole and try to insert a long screw in a hole meant for a shorter screw, it can damage the logic board of the device. This will cause an iPhone boot loop and a blue screen. Performing a DFU restore will not resolve this issue, it will result in an error.

How can this problem be fixed?

The difficulty of resolving this problem will depend on the extent of the damage to your device’s circuit board. The first thing to try is to disassemble your iPhone, unscrew the aforementioned screws and ensure that each screw is replaced in an appropriate hole. Of the four screw holes, the lower right hole is the shortest. Make sure that a screw longer than 1.2 mm does not go into this hole. After this is done, carefully reassemble the iPhone and try turning it on. If your device’s logic board has not been rendered nonfunctional by damage, this will resolve the problem and the iPhone will start up without enter any boot loops.

If this does not resolve the issue, you will have to perform board level repairs on the iPhone. This requires a microscope as the components tend to be tiny. It wouldn’t be wise to attempt this if you are or inexperienced or lack the necessary knowledge of the iPhone’s circuit components. The lower right screw nut (the 1.2 mm one) will need to be de-soldered from the board. The top layer board material will need to be removed till you expose narrow, golden copper traces. There are seven of these fine copper traces. You will need to repair any damaged copper traces and re-solder the screw nut. Make sure that the appropriate screws go into the screen connectors and reassemble the device. This should fix the iPhone boot loop and the device should start up normally.

Some other things that can cause the boot loop include damage to the U2 chip and problems with the proximity sensor’s flex cable. If the above step did not resolve the problem, you will need to examine these components for damage and replace them if necessary.

If your iPhone experiences a boot loop or a blue screen even after trying the above steps, you will need to take the device to an Apple Store and get it replaced or repaired.

Source: http://www.hcqs.us/blog/fix-iphone-boot-lo...een-replacement

Why iPhone No Service after Battery Replacement?

Linda Chan — Tue, 14 Jun 2016 16:03:17 +0800

If you have recently replaced your iPhone battery, you may be unable to connect to a cellular network from your device. You may be receiving a ‘No service’ or ‘Searching’ message instead. This is very inconvenient because it will prevent you from making or receiving calls and force you to rely on a WiFi connection to connect to the internet; as your cellular data connection will be unavailable.

It is important to understand what causes this problem in order to resolve it. Cellular reception problems are commonly caused by software problems, but the issue can also be a result of malfunctioning hardware. The first step is to identify whether the problem is rooted in the iPhone’s software or hardware.

The most common cause of cellular reception problems after battery replacement is the corruption of time and date data. The iPhone uses the battery to register changes in time and date. When the battery is disconnected during replacement; this data gets reset or corrupted. If the date and time on the device is incorrect, the device is unable to connect to the cellular network. You can check if this is the cause of your ‘no service’ problem by opening the Settings app and navigating to General -> Date & Time. If the date shown in this menu is very old or incorrect, it is likely that setting the correct date and time will fix your reception issues.

Another option is to connect the iPhone to a WiFi network. The iPhone can use the WiFi network to obtain and set the correct time and date. Performing a hard reset is another way to ensure that the device’s time and date data is set correctly. In order hard reset your iPhone, follow the steps as noted below –

1. Press and hold the iPhone’s home and power buttons simultaneously.

2. Continue to hold the buttons for a couple seconds; the iPhone will reboot and an Apple logo will appear.

3. At this point, release the buttons and allow the iPhone to boot normally.

The ‘No Service’ message may also be as a result of malfunctioning hardware components that were damaged during the battery replacement. It is common for pry damage to occur if the battery was removed with excessive force, from the wrong side or without the correct pry tool. In this case, you will have to examine the logic board and identify which components have been damaged or knocked off entirely from the board. Damage to the U16X integrated circuit due to screw damage nicking can prevent the iPhone from connecting to a mobile network.

Finally, if nothing else works; you may wish to check if the iPhone SIM card has been jostled in its tray by some sort of impact. Try removing the SIM card and clean the tray. This will remove dust or other debris obstructing the SIM card and may help resolve the “No Service” issue.

If your cellular reception problem persists even after trying all the above steps, you will need to take your iPhone to an Apple Store for replacement or repair.

Source: www.hcqs.us