S I E M E N S
P T E L T D
ST55 Level 2 Service Manual
Copyright © Siemens Pte Ltd.
Siemens Technical Support Centre
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ICM MP CCQ SLI RHQ
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Internal Use Only
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Unit Description ST55
The mechanical concept of the ST55 as a bar phone type is much similar with other Siemens
series mobile phones.
ST55 can be divided into three main physical blocks, the top cover, middle frame and base cover.
The top cover is composed of internal and external LCD protected by LCD base and lens with
shielding effect. The LCD Lens will joint receiver and top cover.
For the main function assy., there are 2 screws located on the base and 2 on the M/B.
Screwdriver (T5) and tweezers will be used as main tools to perform mechanical repair.
Inside, the middle frame consist a M/B, which carries control and RF section of the mobile, and a
key PCB and microphone directly insert into plug-in connectors to show function. The display
module and vibrator are connected to the board by the board to board connector which is
inserted into a plug-in connector. In case they are defective electrically or mechanically it can be
exchanged very quickly. Camera module and antenna is attached on antenna frame which is
inserted on middle frame. The I/O connector for software upgrading and charging is located on
the bottom of middle frame.
The connector for external RF cable is located at the base cover of the mobile. Battery is
attached on the base cover and fix position with battery knob.
Notice: The ST55 is a dual-band mobile operating on GSM900 and GSM1800.
