Before we take apart our iPod video, there are a couple of things you should know. First, the screen on this iPod is cracked. Since no one at HowStuffWorks volunteered their perfect little iPod as a subject for this author's screwdriver, we turned to eBay to find a damaged unit we could take apart with good conscience. Which brings us to the second thing you should know: iPods are almost as valuable broken as they are in mint condition.
After several last-minute outbids, we found out we had to pay about $200 for a 30-GB iPod video with a cracked LCD -- this was the typical ending price for this type of unit. And a brand-new, sixth-generation one costs $249 and has more storage space. We were left shaking our heads. Are hundreds of people writing articles that incorporate an iPod dissection? Are hundreds of people that addicted to tinkering with high-priced electronics? Are iPods really so hard to get fixed by Apple once the one-year warranty runs out? The New York Times article "Good Luck With That Broken iPod" (February 4, 2006) would suggest the latter, although it's really anybody's guess.
That said, let's pry this baby apart.
For most of the iPod video's functionality, we're dealing with seven primary components:
- Hard drive - 30-GB Toshiba 1.8-inch hard drive
- Battery - rechargeable lithium-ion (700 mAh, 3.7V)
- Click Wheel - navigation via touch-sensitive wheel and mechanical buttons
- Display - 2.5-inch TFT LCD
- Microprocessor - PortalPlayer PP5021C with dual ARM7TDMI cores
- Video chip - Broadcom BCM2722
- Audio chip - Wolfson Microelectronics WM8758 codec
The case actually isn't that difficult to get into -- we used a 6-inch metal putty knife to pry apart the seam. Once you see that you need to get the knife under the thin edge of one side of the casing (instead of driving it straight down), it comes apart pretty quickly. When we pulled it apart we saw the back of the LCD, rear casing, motherboard, headphone/stereo jack and hard drive.
This particular iPod video uses a 30-GB Toshiba 1.8-inch hard drive (model MK3008GAL), featuring 4200 rpm and a USB interface. It weighs 1.7 ounces (48 grams) and fits 30 GB onto a single platter, squeezing in 93.5 gigabits per square inch. To fit so much into so little space, the drive uses smaller and lighter sliders (which keep the right spacing between the read/write heads and the recording surface) and a more sensitive thin-film technology on the heads and the platter. The increased sensitivity allows for a greater number of recorded bits per square inch.
When you remove the front casing, you're looking at the LCD, the motherboard and the Click Wheel. The Click Wheel is a section unto itself, and we'll deal with that technology on the next page. Let's start here with the iPod video display.
The display is a 2.5-inch, 16-bit, TFT LCD. It has a 320x240-pixel resolution and a 0.156 dot pitch. The screen is incredibly thin -- just 0.125 inches (3.175 mm) deep.
The connectors used in the iPod are miniscule. Instead of the plastic connectors you find in larger devices, the ends of the wires that connect the various components of the iPod are coated in a film that stiffens them to create a viable input.
All of the chips and memory devices that make an iPod run are situated on the motherboard.
A "mixed-signal array" is a chip that can deal with both analog and digital data. In the case of the Click Wheel, the controller has to accept analog data generated by the movement of a finger over the surface of the wheel and turn it into digital data the microprocessor can understand. Let's find out how it does that.