Secrets of the iPod and iTunes (Fifth Edition) [Electronic resources] نسخه متنی

Opening the Third-generation iPod

The second- and third-generation iPods are tougher to crack (and easier to damage) because the metal back wraps around the ports. If you wrench away the back plate improperly on a third-generation iPod, you could break the internal connections to the data/power and audio ports, thus turning your iPod into a very expensive paperweight.

But being the kind of person who, seconds after unwrapping the latest digital gewgaw, wonders what makes it tick, I understand that some of you won't be satisfied until you know what the inside of a new iPod looks like. Fine. Allow me to save you the trouble (and risk) of opening your musical pal by taking you on a tour of the third-generation iPod.

The Hard Drive

When you open a third-generation iPod, you'll find the hard drive, rather than the battery, on top. As I mention in the sidebar "Can You Upgrade the Hard Drive and Battery?" earlier in this chapter, this iPod carries a Toshiba hard drive that's the same dimensions and weight as the drives in the earlier iPods. (The 15 and 20 GB hard drives are the same size and weight as the earlier 5 and 10 GB drives, and the 30 and 40 GB drives are approximately the same size and weight as the hard drive in the earlier 20 GB model.)

The hard drive is surrounded by a blue plastic grommet that acts as a shock absorber. It's plugged into a data connector that's attached to a flexible polymer EMI shield assembly (made of this same shock-absorbent material). The shield assembly bears a data connector on the bottom that plugs into the iPod's circuit board.

The Battery

The lithium polymer battery is far smaller than the battery used in the first- and second-generation iPods. About the size of an after-dinner mint, the battery rests against the front of the iPod's case in the bottom-left corner (as you're looking at the iPod's front).

The Circuit Board

The iPod's circuit board (Figure 10.12), which is cut out in such a way that it surrounds the battery on three sides, hosts the components necessary for the iPod to do its job. Here, you'll find the following items:

The FireWire controller chip.
As the name implies, this Texas Instruments TSB43AA82 chip controls the iPod's FireWire func-tions. This chip is the same FireWire controller chip used in earlier iPod models.

The USB 2.0 controller chip.
The third-generation iPod supports USB 2.0, and Cyprus Semiconductor's CY7C68013 is the chip behind that magic.

The SDRAM chip.
This chip is much smaller than its predecessor in first- and second-generation iPods. The 32 MB Samsung K4S561633C-RL75 chip serves as the iPod's 25-minute music buffer. Music is read from the hard drive and moved into this chip, allowing the hard drive to spin down (thus saving battery power). When the buffer is nearly empty, the hard drive spins back up and loads additional music into the chip.

The Central Processing Unit (CPU).
The PortalPlayer PP5002D_C chip takes care of processing music on the iPod, including encoding and decoding MP3 and AAC files and producing effects such as EQ and bass boost.

The Digital Audio Converter (DAC) chip.
On the flip side of the circuit board is the DAC chip, which is responsible for delivering sound through the headphone and data/power ports.

The choice of DAC chip used in third-generation iPods is important because, unlike the DAC chips in the first- and second-generation iPods, the new iPod's Wolfson Microelectronics WM8731L supports both audio out and audio inmeaning that you can record audio with this chip. This chip is what allows the Belkin Voice Recorder attachment to do its job.

It's What's Inside That Counts: Disassembling the Third-generation iPod

1. Turn off the iPod, and engage its Hold switch so that it doesn't turn on while you're working on it.

2. Place the iPod face down, and insert a very small, thin flat-head screwdriver between the metal back and acrylic lip of the iPod six centimeters from the top-left side of the iPod, creating a space large enough to insert the corner of a credit card.

3. Carefully run that credit card around the edge of the iPod, moving up toward the top-left corner first.

4. When the back plate is loose, turn the iPod over so that the metal plate is facing you and the iPod's headphone port is pointing up.

5. Push the back plate up slightly to clear the external Hold switch from the internal hold toggle switch.

Failing to do this could cause the internal toggle switch to break.

6. Carefully lift the iPod's back plate to the right, as though you were turning back a page in this book.

Don't pull the back plate directly away from the front case; an internal audio connector attached to the back plate is connected to the case.

7. Detach the back plate's audio connector from the connector on the circuit board (Figure 10.13).

8. To detach the hard drive, carefully lift up the EMI shield assembly, and detach the data connector that sits beneath the copper tape on the left side of the iPod's circuit board (Figure 10.14).

9. To remove the battery, detach the power connector in the bottom-right corner of the circuit board with a pair of needle-nosed pliers, untangle the power cable, and lift out the battery.

10. To reassemble the iPod, reverse these steps.

Make sure that the external Hold switch is in the same position it was in when you disassembled the iPod (in the Hold position). If it's in the "unheld" position, you could snap off the internal hold toggle switch.

Monkeying with the Fourth-generation iPod and the iPod Photo

If, like me, you've developed the bad habit of opening (and usually destroying) every new iPod model that graces your workbench, you'll be happy to know that you needn't learn any new skills to crack open a fourth-generation iPod or iPod Photo. Apple used the same headphone-assembly-attached-to-back-plate scheme it used with the third-generation iPods. If you follow the instructions for carefully folding the back plate away from the front of the iPod that I outlined in my third-generation disassembly instructions, you and your iPod will be fine.

Because the procedure for pulling the fourth-generation iPod and iPod Photo apart is so similar to the third-generation iPod, I've determined to not waste your time by pointing out the finer points of the motherboard and hard drive. Suffice it to say that the hard drive sits atop the motherboard and that the important chips attached to the motherboard are similar to what you find in the iPod mini. (In terms of technology, the fourth-generation iPod, iPod Photo, and mini have more in common than the fourth-generation and previous white iPods.)

I will mention, however, that removing the battery from a fourth-generation iPod and iPod Photo is a little more difficult than pulling the battery from a third-generation model. Apple attaches the fourth-generation iPod's battery to the back of the click-wheel assembly with a bit of adhesive. If you want to remove the battery one day, you should direct the output of a warmish hair dryer to the battery to loosen this adhesive.

Once you've loosened the battery, don't jerk it away from the click wheel. The click wheel's ribbon connector is under the battery, and if this ribbon connector is stuck to the battery as you pull it away, you could damage it and ruin your iPod. If you must remove your iPod's battery, do so slowly and carefully (or, better yet, have a trained professional perform the job).