Huawei U8655N User manual

U8655N
Maintenance Manual
Issue
1.0
Date
2012-09-27
HUAWEI TECHNOLOGIES CO., LTD.

Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
i
Copyright © Huawei Technologies Co., Ltd. 2012. All rights reserved.
No part of this document may be reproduced or transmitted in any form or by any means without prior
written consent of Huawei Technologies Co., Ltd.
Trademarks and Permissions
and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.
All other trademarks and trade names mentioned in this document are the property of their respective
holders.
Notice
The purchased products, services and features are stipulated by the contract made between Huawei and
the customer. All or part of the products, services and features described in this document may not be
within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,
information, and recommendations in this document are provided "AS IS" without warranties, guarantees or
representations of any kind, either express or implied.
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute a warranty of any kind, express or implied.
Huawei Technologies Co., Ltd.
Address:
Huawei Industrial Base
Bantian, Longgang
Shenzhen 518129
People's Republic of China
Website:
http://www.huawei.com
Email:
[email protected]

U8655
Maintenance Manual
About This Document
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
ii
About This Document
Purpose
Prepared by
R&D
Date
Reviewed by
Maintenance support team
Date
Approved by
Service representative
Date
Change History
Date
Version
Change Reason
Revised Section
Description
Author
2012-02-20
V1.0
Released the first issue.
R&D

U8655
Maintenance Manual
Contents
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
iii
Contents
About This Document.................................................................................................................... ii
1 Product Introduction ....................................................................................................................1
1.1 Appearance.......................................................................................................................................................1
1.2 Specifications...................................................................................................................................................1
2 Applicable Scope and Precautions ............................................................................................3
2.1 Applicable Scope..............................................................................................................................................3
2.2 Precautions.......................................................................................................................................................3
2.3 How to Obtain Product and Repair Information ..............................................................................................3
3 Exploded View...............................................................................................................................4
4 Components on the PCBA...........................................................................................................6
5 Software Upgrade .........................................................................................................................8
5.1 Upgrade Preparation.........................................................................................................................................8
5.2 Upgrade Procedure...........................................................................................................................................8
6 Maintenance Tools......................................................................................................................10
7 Disassembly Procedure..............................................................................................................12
8 Assembly Procedure...................................................................................................................17
9 Principles and Failure Analysis ...............................................................................................21
9.1 Block Diagram ...............................................................................................................................................21
9.1.1 Function Description of the PCBA .......................................................................................................22
9.2 Baseband Unit................................................................................................................................................25
9.2.1 Power-on Management Circuits............................................................................................................25
9.2.2 Charging Management Circuits ............................................................................................................29
9.3 RF Unit...........................................................................................................................................................30
9.3.1 RF Failure .............................................................................................................................................30
9.3.2 GPS.......................................................................................................................................................33
9.3.3 Wi-Fi/Bluetooth/FM Module ................................................................................................................33
9.4 Peripheral Circuits..........................................................................................................................................34
9.4.1 Display..................................................................................................................................................34
9.4.2 Camera..................................................................................................................................................37

U8655
Maintenance Manual
Contents
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9.4.3 USB.......................................................................................................................................................39
9.4.4 Headset Jack..........................................................................................................................................40
9.4.5 Keys......................................................................................................................................................42
9.4.6 Status Indicator and Touch Key Backlight Circuits ..............................................................................43
9.4.7 Battery Connector .................................................................................................................................44
9.4.8 Accelerometer .......................................................................................................................................45
9.4.9 Proximity and Illuminance Sensor........................................................................................................45
9.4.10 Vibration Motor...................................................................................................................................47
9.4.11 Receiver ..............................................................................................................................................48
9.4.12 Microphone.........................................................................................................................................50
9.4.13 Touchscreen Panel...............................................................................................................................51
9.4.14 SIM Card.............................................................................................................................................52
9.4.15 microSD Card .....................................................................................................................................53
9.4.16 NFC.....................................................................................................................................................54
10 Solder Points on the PCB and BGA Chip.............................................................................59
11 Functional Tests.........................................................................................................................64
11.1 MMI Test......................................................................................................................................................64
11.2 Voice Call Test..............................................................................................................................................67

U8655
Maintenance Manual
1 Product Introduction
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
1
1 Product Introduction
1.1 Appearance
1.2 Specifications
Category
Description
Dimensions (H x W x D)
116.9 mm x 61.4 mm x 12.2 mm
Technical standard
U8655N: W2100/W900, GSM850/900/1800/1900

U8655
Maintenance Manual
1 Product Introduction
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
2
Category
Description
Frequency bands
U8655N:
WCDMA 900MHz: 880–915 MHz (UL), 925–960 MHz (DL))
WCDMA 2100 MHz: 1920–1980 MHz (UL), 2110–2170 MHz (DL)
GSM 850 MHz: 824–849 MHz (UL), 869–894 MHz (DL)
GSM 900 MHz: 880–915 MHz (UL), 925–960 MHz (DL)
GSM 1800 MHz: 1710–1785 MHz (UL), 1805–1880 MHz (DL)
GSM 1900 MHz: 1850–1910 MHz (UL), 1930–1990 MHz (DL)
Weight
< 125 g with battery
Form factor
Bar
Antenna
Built-in
UIM
SIM, USIM
Charger
5 V, 1000 mA
Battery
Type: Li-ion
Capacity: 1250 mAh
Standby time: 220–250 hours (network dependent)
Talk time: 210 minutes (network dependent)
Display
Resolution
320 x 480 pixels
Type
TFT LCD
Color
262K
Size
3.5 inches
Connectors
Charging port
micro-USB connector
USB port
micro-USB connector
microSD card
interface
microSD card interface
Headset jack
3.5 mm (LRGM)
Maximum
transmission
power
23–33 dBm
Static
sensitivity
≤ 104 dBm
Temperature
Operating temperature: 0°C to +40°C
Storage temperature: –20°C to +50°C
Humidity
Operating humidity: 5% to 95% RH

U8655
Maintenance Manual
2 Applicable Scope and Precautions
Issue 1.0 (2012-02-23)
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Copyright © Huawei Technologies Co., Ltd.
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2 Applicable Scope and Precautions
2.1 Applicable Scope
This document provides repair instructions for technicians at service centers authorized by
Huawei. This maintenance manual is confidential and accessible to authorized service centers
(ASCs) and authorized service providers (ASPs) only. While every effort has been made to
ensure the accuracy of this document, errors may still exist. If you find any errors or have any
suggestions, please contact Huawei’s customer service.
2.2 Precautions
Only qualified technicians are allowed to perform repair and calibration.
Perform all operations in electrostatic discharge (ESD) rooms and wear ESD wrist straps
throughout the operations.
Ensure that all components, screws and insulators are properly installed after repair and
calibration, and that all cables and wires are installed and connected correctly.
Ensure that the soldering is lead-free and compliant with eco-friendly requirements.
2.3 How to Obtain Product and Repair Information
To obtain description and repair information about Huawei's products, please visit
http://www.huaweidevice.com/worldwide/technicaIndex.do.
ESD is the main cause of damage to electrostatic-sensitive components. Each
ASC must exercise caution to avoid ESD damage and comply with the ESD
protection requirements in this manual.

U8655
Maintenance Manual
3 Exploded View
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3 Exploded View
The components listed in the following table are structural parts of the phone, and cannot be
used as reference when requesting spare parts.
Table 3-1 List of components in the exploded view drawing
No.
Item
Quantity
1
U8655N_Cover A assembly
1
2
Touchscreen panel
1
3
U8655N_Cover B assembly
1
4
U8655N_Battery cover assembly
1
5
U8655N_Volume key
1
1
5

U8655
Maintenance Manual
3 Exploded View
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
5
No.
Item
Quantity
6
U8655N_Speaker shielding cover
1
7
U8655N_CPU shielding cover
1
8
U8655N_RTR shielding cover
1
9
U8655N_PA shielding cover
1
10
U8655N_Proximity and illuminance sensor sealing sheath
1
11
U8655N_MIC_sheath
1
12
U8655N_LCD_conductive fabric
2
13
U8655N_Headset insulation film
1
14
U8655N_USB_adhesive film
1
15
Screw M1.4*3.5
1
16
Diversity antenna and Wi-Fi antenna
1
17
Bluetooth antenna
1
18
Main antenna
1
19
LCD
1
20
Power key flexible flat cable (FFC)
1
21
Receiver
1
22
PCBA
1
23
Volume key FFC
1
24
Camera
1
25
Speaker
1
26
Battery
1
27
NFC antenna
1