22 Sep 2008 11:48
CNET Networks' TechRepublic runs a regular series called 'Cracking Open' which takes a look inside a variety of gadgets. ZDNet.co.uk is publishing this excerpt.
The Kindle's front cover contains the screen, navigation bar display, Qwerty keyboard, page-navigation buttons and scroll wheel.
The Kindle uses a six-inch, diagonal, E Ink electronic-paper display, offering 600-by-800 pixel resolution at 167ppi and a four-level greyscale.
The Kindle is 7.5 inches tall, 5.3 inches wide and 0.7 inches thick. The device weighs around 292g.
With the case screws removed, the Kindle's case can now be popped open.
I held the Kindle upright (as shown in this photo), inserted a thin, plastic tool (a fingernail would suffice) into the groove between the case's front and back halves, and gently pushed straight down.
Sliding the tool around the Kindle's case, the plastic catches popped loose. Care was taken not to crack the Kindle's plastic case.
With the case's back panel removed, we get our first look inside the Kindle. Most of the Kindle's circuitry is located on the main PCB.
The SD card reader, speaker, power and wireless on/off switches, cellular card and antennas, and scroll wheel are clearly visible. The thin, contoured metal plate covering most of the Kindle's chips is an EMI shield.
Lifting up the metal EMI shield, the ribbon cable connector for the Kindle's SD card reader can be found.
To remove the Kindle's SD card reader, this ribbon cable needs to be disconnected from the connector on the mail PCB.
These tiny connectors are easily broken, and nearly impossible to fix when damaged.
The Kindle uses Amazon's trademarked Whispernet service to wirelessly download material.
The Kindle has two cellular antennas: a dipole 26.5mm antenna (shown here) and an antenna built into the keypad PCB.
Before lifting the main PCB away from the Kindle's case, the antenna wires need to be disconnected from each antenna. On this antenna, the connector is on the underside and difficult to disconnect without first removing the antenna from the case.
The antenna is held to the case with small amount of adhesive. The antenna can be gently pried away from the case. With the antenna free from the case, the wire can be disconnected.
This flat, metal spring, provides tension for the 'prev page' button on the Kindle's left side.
It is held in place by one of the Phillips 000 screws removed earlier.
As the grey antenna wire runs under this spring, it need to be removed before lifting the main PCB away from the case.
From this angle, you can see the correct placement of the Kindle's E Ink display ribbon cable within the main PCB connector.
The connector's gate is fully open. When reassembling the Kindle, it is important to insert the ribbon cable until the white line is even with the connector's front edge. Slight pressure must be applied to fully insert the cable.
When I first reassembled the Kindle, this cable was not fully inserted and the display did not function. I had to open the Kindle again and reinsert the cable.
With the SD card reader and all the screws removed, and the cables disconnected, the Kindle's main PCB can be lifted away from the case.
This Kindle accesses Sprint's EVDO data network via the AnyData DTEV-Dual 3G CDMA EVDO Module. According to AnyData documentation, the DTEV-Dual provides a wireless data connection up to 2.4Mbps and supports both CDMA 800MHz and 1900MHz. These wireless standards are specific to the US; any European version of the Kindle would need a different module.
The DTEV-Dual also supports voice, a 1.3-megapixel camera, MP3, colour LCD, SD slot, and USB host or slave mode.
Removing the EMI shield gives a clear view of the Kindle's main chips.
The Kindle's main processor is a Marvell PXA255 application processor, with the following markings: LUPXA255A0 G7171929.2 0744 KR C400.
According to Wikipedia, Intel released the PXA210 and PXA25x family (PXA250 and PXA255) of XScale processors in 2002 as a replacement for its StrongARM line of processors.
XScale microprocessors are fifth-generation ARM processors based on ARMv5TE architecture. According to Intel's PXA255 datasheet on Alldatasheet.com, the PXA255 supports a flexible CPU clock speed from 100 to 400MHz. The 'C400' marking on the Kindle's chip indicates this is the 400MHz version.
In some Kindle devices, these chips have an Intel logo. Intel sold the PXA processor assets to Marvell in 2006.
Just above the Kindle's headphone, mini-USB and power jacks, can be found a Wolfson Microelectronics WM8971 stereo, audio codec chip, with the following markings: WM8971G 78AV7N7.
According to Wolfson documentation, "the WM8971L [which seems to have replaced the WM8971G] is a low-power, high-quality stereo codec designed for portable digital audio applications."
Wolfson's site advises against using this chip for new designs and recommends the WM8750 as an alternative.
This photo shows the Amazon Kindle completely disassembled.
The Kindle was surprisingly easy to crack open. The process required no special tools and took about 30 minutes. The tiny ribbon cables and connectors provided most of the difficulty.
Except for the E Ink ribbon cable, which gave me a little trouble, reassembling the Kindle was equally straightforward. When put back together, our Kindle worked perfectly.
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