NOTICE: This documentation if for learning purposes only and does not imply that the reader should proceed to disassemble an iPhone without experience. It is recommended that the reader resort to additional documentation and/or take a certification course regarding this subject matter, prior to dismantling an iPhone.
Replacing a broken screen for the iPhone 4/4s requires disconnecting 11 components from the logic board, plus complete removal of 5 of these components. This process is necessary since the logic board and other parts, such as the battery and speaker are blocking access to the screws that hold the screen component together and must be removed.
Before even attempting to explain what the components are and where they are located, there is one definition that everyone needs to understand and that is what the Digitizer is. In one sentence, it is the (invisible) part of the screen that is sensitive to the touch and sends an instruction from the specific area that is touched to act on that event respectively. In a hardware related explanation, it is the thin capacitive film on the glass that converts analog touch signals to digital responses by the processor.
In addition, the tiny screws that will be removed for the components are NOT the same size. They may look similar in size, but they differ by the mm; however, the small change in size does not affect the Philips tool that can be used to remove them; another words, you don’t need to keep switching for different Phillips tools.
Getting acquainted with the iPhone 4/4s internal components would be a good start before we remove them, so in the image below, we describe the components, their location and their function. All of these components are attached to the logic board, which, as explained above, must be removed.
The connecting cables are called flex cables. They are small, thin and of course, need to be handled with care. Below is a photo of all the installed components but with the cover removed.
iPhone 4 After Cover Removed
Some of the components shown in the photo are blocked in view by the EMI (Electromagnetic Interference) shields (see below). These shields help to reduce noise from outside sources that have electric currents, such as a radio. The shield covers the audio, power, front, rear, digitizer and LCD connectors. There is also and EMI shield that covers the Wi-Fi connector.
Locations of Components for iPhone 4
So now that you have familiarized yourself with the components of an iPhone 4, where they are located and why they need to be disconnected and/or removed, we can continue with actual disassembly of them.