Sony-Ericsson K750 Service Manual Trouble Shooting

Trouble Shooting Guide, Mechanical

Applicable for K750

Contents

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

General...........................................................................................2

1.1. Service functions in the software....................................2

1.2. Misuse and other no warranty issues.............................3

Appearance Problems....................................................................6

Network/Signal Problems ...............................................................9

On/Off Problems...........................................................................10

Audio Problems ............................................................................12

Key Problems ...............................................................................16

Display Problems..........................................................................19

Illumination Problems ...................................................................21

Alert Problems..............................................................................23

SIM Problems...............................................................................25

Charging/Capacity Problems........................................................26

Camera Problems.........................................................................27

Data Communication Problems....................................................30

Hands-Free Problems...................................................................32

Software Problems .......................................................................32

Revision History............................................................................33

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Trouble Shooting Guide, Mechanical

1 General

This document outlines the mechanical repairs that should be made in an attempt to fix the common failures that are seen in the field. To gain a complete understanding of how to test and repair a specific failure, this document should be used in conjunction with the Test Instructions, Mechanical and the Working Instructions, Mechanical.

1.1. Service functions in the software

The service menu will be accessed with the following key combination. Use the joystick.

⇒*⇐⇐*⇐*

They are as follows:

Service info Service tests Text labels

The phones software has a built in service functionality that allows you to test some of the phones functions. (See point 2 above) It looks like this:

Main display LED/illumination Keyboard Speaker Earphone Microphone Vibrator Camera Flash LED Memory Stick Real time clock FM radio (You need a headset to test) Total call time

NOTE: Different names may occur depending on language setting and customization.

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1.2. Misuse and other no warranty issues

Misuse is not covered by warranty. This chapter will explain what’s not covered by warranty. Phones that have been exposed to misuse will not be covered by warranty.

This means: if it is possible to repair the phone, the customer will have to pay for the repair. SEMC will not allow any of these phones to be claimed into WCMS. Some local perspectives may interfere with this. Please reference to local directives.

1.1.1 Action

Make a general visual inspection for misuse. Below are some examples of what is not covered by warranty.

Front window broken due

to misuse.

Corrosion components on the PCB. Corrosion components on the PCB. SIM reader damaged by liquid. System connector damaged by liquid

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LCD cracked due to

drop.

Clear scratches Mark after drop

Corrosion components on

the PCB.

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Components around system connector damaged by liquid

System connector pad(s) damaged by liquid

1.1.2 Liquid damage sticker

In the phone there is placed a sticker that can give you a hint to see if the phone is damage by liquid or not. This sticker is located near the SIM reader (Fig. 1.2.1) and it is possible to see it without disassemble the phone.

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Fig. 1.2.1

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On the pictures below you will see the different between a sticker that has been in contact with liquid (Fig. 1.2.3) and with one that hasn’t (Fig.

1.2.2).

This sticker is ok This sticker is not

1.1.3 Action

Make a general visual inspection for misuse, corrosion or oxidation from liquid damage. No further action should be taken for a liquid damaged phone. Handle the unit according to local directives.

Fig. 1.2.2 Fig. 1.2.3

The white sticker that has been in contact with liquid turns into a red or pink sticker. In this case you should check the phone for liquid damage (See point 1.1.1).

Note: There must be clear marks after liquid on the PCB before rejecting the phone for repair.

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2 Appearance Problems

Problem Area Items to Check Repair Action Reference Image

Appearance

Visually inspect the cosmetic quality of all user viewable surfaces

Front System connector Joystick button Frame assembly IRDA window Memory card rubber lid Antenna cover assembly Battery cover assembly Co-brand inlay

• If dirty – Clean parts as necessary.

• If unacceptably scratched or damaged –

Replace damage parts as necessary.

NOTE: Misuse is not covered by warranty. Refer to chapter 1.2

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Problem Area Items to Check Repair Action Reference Image

Visually inspect all keys Keyboard

On/Off key Music key Volume key Camera key

• If dirty – Clean parts as necessary.

• If unacceptably scratched or damaged –

Replace damaged parts as necessary.

NOTE: Misuse is not covered by warranty. Refer to chapter 1.2

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Problem Area Items to Check Repair Action Reference Image

Visually inspect for improper gap between seams

• Reassemble or replace damaged parts as necessary.

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3 Network/Signal Problems

Problem Area Items to Check Repair Action Reference Image

No Signal or Poor Signal

Before proceeding ! Perform a flash upgrade. Visually inspect SIM holder

Visually inspect antenna contact pads

• If dirty or oxidized – Clean it.

• If damaged – Send to an electrical repair

location.

• If dirty or oxidized – Clean the pads and replace the antenna assembly.

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Problem Area Items to Check Repair Action Reference Image

Visually inspect antenna

• If dirty or oxidized – Replace it.

• If damaged – Replace it.

If the issue has not been resolved !

4 On/Off Problems

Problem Area Items to Check Repair Action Reference Image

Power On problems

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Check whether the phone vibrates 10 to 15 seconds after pressing the power key and whether the keypad illuminates

Before proceeding !

• Handle the unit according to local directives.

• If activation of the vibrator and keypad are detected, refer to the “Display Problems” section

• Perform a flash upgrade.

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