The printed circuit board -- more commonly called the logic board -- in an iPod is the component to which all the iPod's other components connect. The PCB is the iPod's "brain" and the highway on which data travels. Replacing the PCB can be a challenge for technical novices, but a nonfunctioning PCB renders an iPod unusable. Microprocessor and Firmware Data Path Diagnosing a Failed PCB Replacing a Failed PCB
An iPod's PCB contains a microprocessor and a chip for storing the system firmware. The firmware includes the iPod's operating system and instructions for decoding the audio and video formats the iPod supports, such as MP3 and AAC audio and H.264 video. The microprocessor -- like the one in your computer -- provides the computation power needed to execute these instructions.
The iPod's PCB has numerous metal interconnects that serve as data pathways. All the iPod's components -- such as the hard drive, control pad, headphone jack and screen -- connect to the PCB. Data travels from the hard drive to a small memory buffer where it is decoded by the microprocessor. The microprocessor sends the result to a digital-to-analog converter, which converts the data to analog audio and sends it to the headphone jack. The data travels over the PCB during each step of this process.
It can be difficult to diagnose a failed iPod PCB because several other problems can cause an iPod to stop working. Some possible signs include an image of a sad iPod on the screen or the prompt "Use iTunes to Restore." You may also find that the iPod does not turn on, even when connected to a power source. In some cases, an iPod with a failed PCB may display an Apple logo continuously or reboot at random times.
To open an iPod and remove a failed PCB, you need a small plastic tool for prying the two halves of the iPod apart. After separating the iPod, look for the ribbon cables connecting the hard drive and headphone jack to the PCB. Removing the hard drive allows you to access the PCB. Disconnect the red and black battery cable as well as the ribbon cables for the screen and control pad. You can then remove the Torx screws anchoring the PCB to the body of the iPod and remove the PCB.
