
Troubleshooting Guide
- mechanical -
Xperia
LT39t
1279-7185 Rev 1
Sony Mobile Communications AB – Company Internal
TM
Z1

Troubleshooting Guide (mech)
CONTENTS
1 Problem Areas ................................................................................ 5
1.1 Power .................................................................................................... 5
1.1.1 Will not power on or will switch off randomly ........................................... 5
1.2 Keys ...................................................................................................... 7
1.2.1 Back, Menu, Home and Multitask Keys ..................................................... 7
1.2.2 Volume Key .................................................................................................. 7
1.2.3 On/Off Key .................................................................................................... 8
1.2.4 Camera Key ................................................................................................ 10
1.3 Touch Screen ..................................................................................... 12
1.3.1 Touch Screen malfunction ........................................................................ 12
1.4 Display ................................................................................................ 13
1.4.1 Graphics & Illumination ............................................................................ 13
1.5 LED/Illumination ................................................................................. 14
1.5.1 LED/Illumination ........................................................................................ 14
1.6 Speaker ............................................................................................... 15
1.6.1 Loudspeaker .............................................................................................. 15
1.7 Earphone ............................................................................................ 17
1.7.1 Ear Speaker ................................................................................................ 17
1.8 Microphone ......................................................................................... 18
1.8.1 Primary Microphone .................................................................................. 18
1.8.2 Secondary Microphone ............................................................................. 19
1.9 Vibrator ............................................................................................... 22
1.9.1 Vibrator not generating alerts .................................................................. 22
1.10 Camera ................................................................................................ 24
1.10.1 Main Camera .............................................................................................. 24
1.10.2 Video Call Camera defects ........................................................................ 25
1.11 Flash LED ........................................................................................... 26
1.11.1 Flash LED not flashing .............................................................................. 26
1.12 Bluetooth and WLAN ......................................................................... 28
1.12.1 Bluetooth or WLAN connection failure .................................................... 28
1.13 NFC ..................................................................................................... 29
1.13.1 NFC malfunctions ...................................................................................... 29
1.14 GPS ..................................................................................................... 30
1.14.1 GPS malfunctions ...................................................................................... 30
1.15 Compass ............................................................................................. 31
1.15.1 Compass fails ............................................................................................ 31
1.16 Accelerometer .................................................................................... 32
1.16.1 Accelerometer test fails ............................................................................ 32
1.17 Gyroscope .......................................................................................... 33
1.17.1 Gyroscope test fails .................................................................................. 33
1.18 Ambient Light Sensor ........................................................................ 34
1.18.1 Light Sensor malfunctions ....................................................................... 34
1279-7185 Rev 1
Sony Mobile Communications AB –
2(68)

Troubleshooting Guide (mech)
1.19 Proximity Switch ................................................................................ 36
1.19.1 Proximity switch malfunctions ................................................................. 36
1.20 Pressure Sensor ................................................................................. 38
1.20.1 Pressure Sensor test fails ......................................................................... 38
1.21 Water Resistance ............................................................................... 39
1.21.1 Water Resistance fails............................................................................... 39
1.22 Real Time Clock ................................................................................. 45
1.22.1 Real time clock test fails ........................................................................... 45
1.23 Total call time ..................................................................................... 46
1.23.1 Total call time fails .................................................................................... 46
1.24 External ............................................................................................... 47
1.24.1 Memory Card not detected ....................................................................... 47
1.25 Security ............................................................................................... 48
1.25.1 Security fails .............................................................................................. 48
1.26 FM Radio ............................................................................................. 49
1.26.1 No/Poor FM Radio reception .................................................................... 49
1.27 Battery Health test ............................................................................. 50
1.27.1 Battery Health test fails ............................................................................. 50
1.28 Flip Slider Counter ............................................................................. 51
1.28.1 Flip Slider Counter fails ............................................................................ 51
1.29 Verify Certificates ............................................................................... 52
1.29.1 Verify Certificates fails .............................................................................. 52
1.30 IrDA Test ............................................................................................. 53
1.30.1 IrDA test fails ............................................................................................. 53
1.31 TV-Out Test ......................................................................................... 54
1.31.1 TV-Out test fails ......................................................................................... 54
1.32 Network & Signal ................................................................................ 55
1.32.1 No/Poor signal ........................................................................................... 55
1.33 SIM ...................................................................................................... 62
1.33.1 SIM not detected ........................................................................................ 62
1.33.2 Incorrect UIM or SIM indicated ................................................................. 62
1.34 Charging ............................................................................................. 63
1.34.1 Battery will not charge by USB connector .............................................. 63
1.34.2 Battery will not charge by charge pad ..................................................... 63
1.35 HandsFree by Wire ............................................................................. 66
1.35.1 Connection to portable Handsfree fails ................................................... 66
1.36 Data Communication ......................................................................... 67
1.36.1 Data transfer via System Connector fails ................................................ 67
2 Revision History ........................................................................... 68
1279-7185 Rev 1
Sony Mobile Communications AB –
3(68)

Troubleshooting Guide (mech)
Always firstly disconnect the Battery FPC BtB connector to cut off power supply when the Sub
Antenna Assy is disassembled.
Always finally connect the Battery FPC BtB connector before the Sub Antenna Assy is
reassembled.
1279-7185 Rev 1
Sony Mobile Communications AB –
4(68)

1 Problem Areas
1.1 Power
1.1.1 Will not power on or will switch
off randomly
Check:
Check whether the phone vibrates by pressing the on/off
key.
Action:
1. If activation of the vibrator is detected, refer to section 1.4
‘Display’.
Troubleshooting Guide (mech)
2. If NO activation of the Vibrator is detected, check that the
battery is charging when connected to a charger.
Follow 1279-7188 Test Instruction - mechanical chapter
2.3.7 (Charging via USB and Easy Charger), Diagnostic
Battery / Charging status.
Check:
Inspect the on/off key.
Action:
Refer to section 1.2.3 ‘On/Off Key’.
Check:
Inspect the BtB connector of the Battery to Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean the both sides of the BtB
connector.
1279-7185 Rev 1
Sony Mobile Communications AB –
5(68)

Problem Areas: Power
3. If the BtB connector, the Battery FPC or the Battery is damaged
– replace the Battery.
4. Replace Main PBA.
Troubleshooting Guide (mech)
1279-7185 Rev 1
Sony Mobile Communications AB –
6(68)

Problem Areas
1.2 Keys
1.2.1 Back, Menu, Home and
Multitask Keys
Action:
1. Refer to section 1.3 ‘Touch Screen’.
2. Replace Main PBA.
1.2.2 Volume Key
Check:
Inspect the external area of the Key Volume.
Action:
If dirty – clean it.
Troubleshooting Guide (mech)
Check:
Inspect the BtB connector of FPC Assy Relay/Side Key to
Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
3. If the FPC of FPC Assy Relay/Side Key is damaged –
replace the FPC Assy Relay/Side Key.
4. Replace Main PBA.
1279-7185 Rev 1
Sony Mobile Communications AB –
7(68)

Problem Areas: Keys
Check:
Inspect the rubber of the Volume Key (a) and Volume Key
switch (b).
Action:
1. If dirty – clean them.
Troubleshooting Guide (mech)
2. If the rubber of the Volume Key is damaged – replace the
Display Frame Assy.
3. If the volume key switch is damaged – replace the FPC
Assy Relay/Side Key.
1.2.3 On/Off Key
Check:
Inspect the external area of the Power Key.
Action:
If dirty – clean it.
1279-7185 Rev 1
Sony Mobile Communications AB –
8(68)

Problem Areas: Keys
Check:
Inspect the BtB connector of FPC Assy Relay/Side Key to
Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
3. If the FPC of FPC Assy Relay/Side Key is damaged –
replace the FPC Assy Relay/Side Key.
4. Replace Main PBA.
Troubleshooting Guide (mech)
Check:
Inspect the rubber of the Power Key (a) and Power Key
switch (b).
Action:
1. If dirty – clean them.
2. If the rubber of the power key is damaged – replace the
Display Frame Assy.
1279-7185 Rev 1
Sony Mobile Communications AB –
9(68)

Problem Areas: Keys
3. If the power key switch is damaged – replace the FPC
Assy Relay/Side Key.
1.2.4 Camera Key
Check:
Inspect the external area of the Camera Key.
Action:
If dirty – clean it.
Troubleshooting Guide (mech)
Check:
Inspect the BtB connector of FPC Assy Relay/Side Key to
Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
3. If the FPC of FPC Assy Relay/Side Key is damaged –
replace the FPC Assy Relay/Side Key.
4. Replace Main PBA.
1279-7185 Rev 1
Sony Mobile Communications AB –
10(68)

Problem Areas: Keys
Check:
Inspect the rubber of the Camera Key (a) and Camera Key
switch (b).
Action:
1. If dirty – clean them.
Troubleshooting Guide (mech)
2. If the rubber of the Camera Key is damaged – replace the
Display Frame Assy.
2. If the camera key switch is damaged – replace the FPC
Assy Relay/Side Key.
1279-7185 Rev 1
Sony Mobile Communications AB –
11(68)

Problem Areas
1.3 Touch Screen
1.3.1 Touch Screen malfunction
Check:
Inspect the touch screen of the Display Frame Assy.
Action:
1. If dirty – clean it.
Troubleshooting Guide (mech)
2. If scratched or damaged – replace the Display Frame
Assy.
Check:
Inspect the BtB connector of Display Frame Assy FPC to
Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
3. If the BtB connector of Display Frame Assy FPC or FPC
is damaged – replace the Display Frame Assy.
4. Replace Main PBA.
1279-7185 Rev 1
Sony Mobile Communications AB –
12(68)

Problem Areas
1.4 Display
1.4.1 Graphics & Illumination
Check:
Check whether the phone vibrates after the on/off key has
been pressed.
Action:
If the activation described above is not detected, refer to
section 1.1 ‘Power’.
Check:
Inspect the BtB connector of Display Frame Assy FPC to
Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
Troubleshooting Guide (mech)
3. If the BtB connector of Display Frame Assy FPC or FPC
is damaged – replace the Display Frame Assy.
4. Replace Main PBA.
1279-7185 Rev 1
Sony Mobile Communications AB –
13(68)

Problem Areas
1.5 LED/Illumination
1.5.1 LED/Illumination
Check:
Inspect external port of LED on the Display Frame Assy.
Action:
1. If dirty – clean it.
Check:
Inspect the BtB connector of FPC Assy Audio Jack to Main
PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
Troubleshooting Guide (mech)
3. If the BtB connector of FPC Assy Audio Jack or FPC is
damaged – replace the FPC Assy Audio Jack.
4. Replace Main PBA.
1279-7185 Rev 1
Sony Mobile Communications AB –
14(68)

Problem Areas
1.6 Speaker
1.6.1 Loudspeaker
Check:
Inspect the Speaker Panel on the Display Frame Assy.
Action:
1. If the Speaker Panel is clogged – clean it.
Troubleshooting Guide (mech)
2. If the Speaker Panel is damaged – replace the Speaker
Panel.
Check:
Inspect the contact pads of Loudspeaker and the contact
pads on the FPC Assy Relay/Side Key.
Action:
1. If dirty – clean them.
2. If the contact pads of Loudspeaker or the Loudspeaker
are damaged – replace the Main Antenna Speaker Sub
Assy.
1279-7185 Rev 1
Sony Mobile Communications AB –
15(68)

Problem Areas: Speaker
3. If the contact pads of FPC Assy Relay/Side Key are
damaged - replace the FPC Assy Relay/Side Key.
Check:
Inspect the BtB connector of FPC Assy Relay/Side Key to
Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
Troubleshooting Guide (mech)
3. If the BtB connector of FPC Assy Relay/Side Key or FPC
is damaged – replace the FPC Assy Relay/Side Key.
4. Replace Main PBA.
1279-7185 Rev 1
Sony Mobile Communications AB –
16(68)

Problem Areas
1.7 Earphone
1.7.1 Ear Speaker
Check:
Inspect the external port of Ear Speaker on the Display
Frame Assy.
Action:
1. If clogged – clean it.
Check:
Inspect the contact pads of Ear Speaker and the Ear
Speaker Conductive Films on the Main PBA.
Action:
1. If dirty – clean them.
Troubleshooting Guide (mech)
2. If the contact pads of the Ear Speaker or the Ear Speaker
are damaged – replace the Ear Speaker.
3. If Conductive Film Ear Speaker is damaged – replace
Conductive Film Ear Speaker.
4. Replace Main PBA.
1279-7185 Rev 1
Sony Mobile Communications AB –
17(68)

Problem Areas
1.8 Microphone
1.8.1 Primary Microphone
Check:
Inspect the Speaker Panel on the Display Frame Assy.
Action:
1. If clogged – clean it.
Troubleshooting Guide (mech)
2. If the Speaker Panel is damaged – replace the Speaker
Panel.
Check:
Inspect the microphone on the FPC Assy Relay/Side Key.
Action:
1. If clogged – clean it.
2. If the microphone is damaged – replace the FPC Assy
Relay/Side Key.
Check:
Inspect the 1st Mic Cushion on Display Frame Assy.
Action:
1. If dirty – clean them.
1279-7185 Rev 1
Sony Mobile Communications AB –
18(68)

Problem Areas: Microphone
2. If the 1st Mic Cushion is damaged – replace Display
Frame Assy.
Check:
Inspect the BtB connector of FPC Assy Relay/Side Key to
Main PBA.
Action:
1. If not properly connected – disconnect and reconnect it.
2. If dirty or oxidized – clean it.
Troubleshooting Guide (mech)
3. If the BtB connector of FPC Assy Relay/Side Key or FPC
is damaged – replace the FPC Assy Relay/Side Key.
4. Replace Main PBA.
1.8.2 Secondary Microphone
Check:
Inspect the external port of secondary microphone on the
Window Back Sub Assy.
Action:
1. If clogged – clean it.
1279-7185 Rev 1
Sony Mobile Communications AB –
19(68)

Problem Areas: Microphone
Check:
Inspect the Sheet WP 2nd Mic on the Window Back Sub
Assy.
Action:
1. If dirty – clean them.
Troubleshooting Guide (mech)
2. If the Sheet WP 2nd Mic is damaged – replace the
Window Back Sub Assy.
Check:
Inspect the Holder FPC Assy Audio Jack.
Action:
1. If the Holder FPC Assy Audio Jack is damaged – replace
it.
Check:
Inspect the Gasket 2nd MIC on the main PBA.
Action:
1. If the Gasket 2nd MIC is damaged – replace it.
1279-7185 Rev 1
Sony Mobile Communications AB –
20(68)

Problem Areas: Microphone
2. Replace Main PBA.
Troubleshooting Guide (mech)
1279-7185 Rev 1
Sony Mobile Communications AB –
21(68)