Saturday, January 26, 2013

Teardown highlights from iFixit

Part of the homework this weekend is to read some teardowns at iFixit (each student was assigned 12 to read) and send me an email with a link to your favorite one, with a short explanation of why it's your favorite. Here are the replies that I've received so far:
  • PlayStation Move
  • Cool application of COTS parts (microcontroller used instead of an ASIC,) 5050 RGB LED (my favorite LED package,) magnetometer, gyro, nice battery form-factor, slightly nontrivial mechanical system, with a robust-looking vibrating motor.
  • Mac Pro Early 2009
  • My favorite was the anti-teardown of an early 2009 mac pro. I took apart a similar mac product and the insides, while a huge pain in the butt to remove, were elegant. I think in some cases it was meant to be run without the side panel on, since there was a big plastic window piece underneath it to keep the airflow going through the right way. There were a lot of tricky parts in that computer, like a big, flat, custom PSU (300W or so) that was integrated with the bottom of the case, and fans that could snap in and out of bays. Cool piece of hardware.
  • PlayStation Vita
  • Step 21 of the disassembly of a PS Vita clearly explains how to remove the front panel from the frame: (1) Pre-heat oven to 200 F. (2) Place PS Vita front panel assembly in the oven and set timer for 10 minutes. (3) Remove the PS Vita from the oven and carefully peel the plastic off the front case using several guitar picks. Watch out -- it's hot! The best part is that the author/photographer didn't even bother removing all the bread crumbs from the bottom of his oven before taking a super high-resolution image of the baking Vita.
  • Boxee Box
  • Cool half-sunken-cube form factor, I guess... Actually a real neat form factor and cool innards. I love the triangular power board and using both sides of the remote is very clever.
  • Power Mac G4 Cube
  • It's pretty neat that this mac you take apart by just pulling out the guts like this, the handle pops out like a suitcase handle or something. It's got a unique hardware layout. It seems more robust since you're handling a cube not a flat piece but that could be a case of deceptive looks. It's not actively cooled which is weird; the processor has little breathing room and is up right up against a wall of plastic.
  • PlayStation 3 Slim versus Nintendo Wii
  • I was very much struck at the difference between the PS3 Slim and the Wii. While the PS3 looked like it was actually meant at some point to be serviceable, it looked like Nintendo would just give you another console for the effort it took to take apart - there are small black plastic trims everywhere and screws of varying lengths. Another really telling difference in these two designs were the case fan sizes - compare Sony's massive fan and the Wii's tiny one. I suppose this speaks to the processing power of the respective platforms.

    In general, I appreciated the Sony design. Other than having on it a 'Reality Synthesizer' chip, I thought the layout of the RAM cells was interesting. Since they were using two chips, they made one layout and mirrored it for the second chip. That gave a pretty pattern and also enforced uniformity between the two cells. This picture also has a wide variety of more complicated trace styles in one picture: differential pairs, length matched single-ended traces (the squiggled traces in between the differential pairs a little bit south of the chips), and small power plane areas. I am interested in the fact that the length matched traces seem to come out of vias in between the chips with one trace length, travel for a bit, then widen when entering an area filled with a surrounding ground plane. I would not be surprised if this were to maintain a fifty ohm impedance throughout the traces.
  • Blendtec Total Blender
  • This is the "Will it Blend?" blender, and in addition to being massively powerful (1560W base edition) it includes a bunch of interesting sensors to keep it safe. For example, it has a speed sensor that uses inductive pickup to tell how fast the shaft is spinning, which then sends data to the microprocessor so that if the blade stops spinning it can send pulses to the motor to try to get past the obstruction. Also the logic board has the LCD screen on its reverse, so the blender doesn't need to have another circuit board. For the more mechanically inclined, this teardown also includes some awesome pictures of the beefy blender motor and a weld that is "just plain beautiful" on the stator frame.
  • Starbucks Barista
  • Although this device has very little circuitry, I found some of the electronics particularly interesting. The Barista, a coffee brewing machine, pumps water between reservoirs using a "solenoid-style" action. Basically, an iron core in the pump is actuated to create a pressure difference that causes water to travel through the pump. The cool thing is that this is done without any components besides an activation switch; the iron core oscillates when AC is applied. I figure this is somewhat typical of consumer product design, where lowering cost is a paramount priority.
  • Nook Simple Touch with Glowlight
  • My favorite teardown was that of the Nook Simple Touch with Glowlight. My first reason for choosing this teardown is that it shows an interesting combination of technologies: most of the ICs are leadless (the state of the art), being QFN and (120 ball micro-) BGA, yet it still uses some oldschool 7400-series logic in the form of a '4067 analog switch. It also shows the state of consumer electronics with its tiny (0603?) passive components.

    However, by far the coolest aspect of the teardown is the explanation of the backlighting system: the Nook has a diffraction grating integrated into its glass screen, allowing a single array of LEDs along one side of the screen to illuminate all of it! This is a really interesting approach to backlighting, and shows the ingenuity of its engineers.
  • Apple A4
  • I've never seen the insides of a processor, and the pictures they took with x-ray and high powered optical microscopes were awesome. In step 6 there's an image of a cross section of the A4 package which shows the actual processor in the middle and the RAM on both sides. It's pretty cool that Apple took these lengths to optimize their hardware.
  • MacBook Pro 15" Unibody Mid 2010
  • The Macbook Pro has some cool geometry to its PCB (round cutouts) that allows two fans and heatsinks to be set into the board. I saw this style in a few teardowns. Unlike some of the smaller boards that I saw that grouped like sized components, the large chips on this board were fairly spread out, with smaller components mixed between them. This layout doesn't seem optimal for compactness, but it must be designed for wire routing. It is also interesting how they had to combine larger, heavier wired components like the fans with tiny components on the board. I wonder if they run into issues soldering the large components while some of the smaller, more fragile ones are so near.
  • Canon PowerShot S400
  • I'd never really thought about what's inside a camera as much as iPads, phones, or other teardown subjects. This particular camera is very repairable, as everything is mostly attached by screws and ribbon cables. The coolest part of the teardown is the flexible circuitry in addition to the PCB, which allows the camera to be fairly thin. The flexible circuits wrap around the circular lens to connect different parts of the camera.
  • iPhone 5
  • I have to congratulate Apple if just for the sheer number of components that they manage to fit onto this board. I've taken apart several iPhones in the past along with iPads and macs and the iPhone 5's design gives me some hope that they're going for more repairable construction technique instead of using more glue. Also in reading though the breakdown it's amazing how many tiny screws are in this phone.
  • Motorola Droid RAZR
  • Between the forest of EMI shields, diamond-cut aluminum chassis, and leopard print on the camera’s ribbon cable, it's hard to pick a favorite part of the Droid RAZR. Cell phones are a great example of the need for EMI shields, which I previously didn’t care to think about much. This particular cell phone is so thin which necessitates absolutely beautiful board layout and design as well as crazy precise (diamond-cut) mechanical components. Aside from that, as I was geeking out about the camera hardware, I saw the leopard print ribbon cable. It reminded me of the rainbow spectrum board we saw in class.
  • PlayStation 3
  • I was impressed by how knowledgeable the author of this teardown is. The instructions are the clearest of the teardowns that I read and are very detailed. In addition to simply mentioning which screws to undo or what to pry up, the author describes in what direction forces should be applied and what cables or other parts to be aware/careful of. It was interesting that each part was referred to by name, so you could see all of the components that made up the PS3 and how they connected together.
  • MacBook Air 13" Mid 2012
  • As you can see, the new MagSafe 2 connector (bottom) is much thinner and wider than its predecessor. This is pretty significant, because the thickness of Apple's devices seems to be limited only by the size of their ports. Imagine how thin of a device they could make if all communication and charging were done wirelessly… The wider gaps in the fan blades are around 3.6 mm, while the narrower ones are approximately 2.8 mm. If you're not familiar with all the hype, the "asymmetrical" design of the fan blades is supposed to disperse sound across a wide range of frequencies, rather than just one, making fan noise "hardly perceivable." In order to save weight in the MacBook Air, there is no protective front glass covering the LCD like there is on the MacBook Pro.
  • Samsung Galaxy Nexus
  • Given the aesthetics and extremely smooth and shaped exteriors of many modern touch phones, it was pretty interesting to see how a Galaxy Nexus disassembles. Some of the coolest parts of the teardown were the NFC (near-field communication) traces built into the back of the battery, and the modularity of most of the critical components. The motherboard came assembled in several different pieces all connected via ribbons, and almost all discrete components (speakers, cameras) were removable and replaceable with miniature connectors onto the motherboard(s). I was pretty surprised as well at the variety of chips and controllers included in the electronics of the phone. Many of the features that set this amazing phone apart from others, such as smooth touch screen response and high definition video, were implemented via discrete hardware instead of software processing. Just like a desktop computer, it had separate graphics processing and hardware for processing the different functions of the phone.
  • iMac Intel 27" EMC 2309 and 2374
  • The 27" iMac teardown had a few interesting teardown methods and contained a lot of interesting design decisions. The author had to use two suction cups to take off the front screen and get access to the computer internals behind. The design for the heat dissipation was interesting in that the CPU and GPU are separated with individual heat sinks that dissipate to opposite sides of the computer. They also included six temperature sensors and three fans for heat dissipation. An interesting design decision is the choice of an all-aluminum enclosure. This does not provide good wifi reception, so there is an antenna placed behind the Apple logo because it is the only plastic in the enclosure.
  • iPad 4
  • The most interesting teardown I read was of the iPad 4. I found this one to be particularly interesting because of both the spacial limitations of the product, and the aesthetics of the internal components. It seems that the iPad 4 is mostly a battery. While that's not all that surprising to me, I was impressed by the size of the circuit board. It looks like all of the non peripheral electronic components are on one small rectangular board. Because of the resolution of the screen and the speed of the processor, it is pretty amazing that that such a small board is controlling the entire device. As for the aesthetics, all the PCBs are a uniform color, and it seems like Apple tried to use all straight lines, while avoiding sharp corners on the device's components. I don't know if I would call it "beautiful," but someone clearly worked very hard to make everything visually appealing.

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