[Solar Phone Teardown] Main Board of 'All-inclusive' Mobile Phone [Part 4]

Jun 29, 2009
Nikkei Electronics Teardown Squad

Continued from [Solar Phone Teardown] Design Around Solar Cell Module [Part 3]

After finishing the disassembly of the display unit of the Solar Phone SH002, a mobile phone mounted with a solar cell module, Nikkei Electronics Teardown Squad started to tear down the chassis on the keyboard side.

The SH002 is an "all-inclusive" model that comes with most of the functions for high-end models, such as 1seg digital TV reception, electronic payment by FeliCa, GPS reception and sending and receiving via Bluetooth, in addition to the charging function with the solar cell module and the waterproof property that complies with IPX5/IPX7 standards. The aim of the teardown is to check the parts mounted on the main board.

Usually, the lower chassis of a handset is not assembled with cross- or straight-slot screws, but it uses screws in other shapes. In fact, we found four star-shaped screws under the cover of the battery.

Four star-shaped screws found under the battery cover

After removing the four screws, we tried to pry open the chassis with a screwdriver and failed. It was because there were two more star-shaped screws under the resin cover for the 520-Mpixel camera module. By taking out the two screws, we managed to break down the lower chassis. The screw of the same shape is used in the fixed portion of the external 1seg antenna.

The star-shaped screws found under the resin cover for the 520-Mpixel camera module
The screw is also used in the fixed portion of the external 1seg antenna.

We examined the inside of the lower chassis and found that it is mounted with two printed boards, the main antenna for CDMA2000 1x EV-DO and an antenna for Bluetooth and GPS. The waterproof property of the lower chassis was realized by adding rubber waterproof gaskets to the battery cover and between the two parts of the lower chassis.

We opened the lower chassis of the handset (on the keyboard side).

Next, we pulled out the main board. Most of the main components, such as the RF circuit and digital signal processing circuit, are mounted on a single side of the main board. The SH002 is equipped with Qualcomm Inc's "MSM7500," a standard chipset for mobile phones that use the common platform "KCP+." KCP+ was developed by Qualcomm and KDDI for au brand mobile phones.

On the sub board, there are only a 1seg tuner module, sending/receiving circuits for FeliCa and so forth.

The main board (top side) of the SH002 features "MSM7500," Qualcomm Inc's chipset designed for mobile phones.
The main board (under side) of the SH002, which is mounted with few components including a SIM card slot and microSD card slot
The sub board of the SH002. The module seen in the center left is the 1seg tuner module. The two chips at the bottom are sending/receiving circuits for FeliCa.