Sony-Ericsson K750 Service Manual WORKING INSTRUCTION

K750 Working Instructions - electrical

Working Instructions - electrical

Applicable for K750i / K750c

Contents

1 Lead-free soldering................................................................................3

2 BGA equipment reflow profiles.............................................................6

2.1 General........................................................................................6

2.2 Temperature measurement.........................................................6

2.3 Reflow profiles.............................................................................7

3 Replacement of parts.............................................................................8

3.1 Backup capacitor.........................................................................9

3.2 External antenna switch...............................................................9

3.3 Camera connector BtB 30 pin....................................................10

3.4 LCD connector BtB 20 pin.........................................................11

3.5 Keyboard connector BtB 20 pin.................................................12

3.6 SIM reader.................................................................................13

3.7 Battery connector ......................................................................13

3.8 Memory stick Duo reader...........................................................14

3.9 IrDA ...........................................................................................14

3.10 Joystick switch...........................................................................15

3.11 Side key switch..........................................................................15

3.12 Microphone................................................................................16

3.13 Red LED....................................................................................17

Diode/ESD protector ..................................................................18

3.14

3.15 Quartz crystal unit......................................................................19

3.16 Prod adapt circuit/ASIC Tjatte 2 ................................................20

3.17 Prod adapt circuit/ASIC Vincenne .............................................21

3.18 Mini T-top...................................................................................22

4 Revision History...................................................................................23

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

K750 Working Instructions - electrical

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

2(23)

K750 Working Instructions - electrical

1 Lead-free soldering

Caution

Keep all contact surfaces clean of dirt and hand grease.

This product is manufactured with lead-free

solder and lead-free components!

During electrical repair, it is critical to make sure
that no lead is introduced.

This symbol indicates that the product is lead­free.

All lead-free PBA’s will be marked with this
symbol.

A lead-free work area must be set up completely
separated from work areas that are used to make
lead repairs.

The lead-free work area must also be clearly
labeled with the lead free symbol as shown in the
adjacent picture.

The items on this desk must remain lead-free.
They must be adequately labeled to make their

lead-free status clearly and easily recognized.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

3(23)

K750 Working Instructions - electrical

LFS (lead-free solder paste) characteristics:

• High melting point (typically 220°C)

• Low wettability

• High surface tension

• Difficult to spread

• Recommended tip temperature = 370°C

When servicing PBA’s that have been

manufactured with LFS (lead-free solder paste),
LFS must

If not, there is a high risk for unreliable

soldering joints.

be used.

Lead-free solder joints are more difficult to
inspect because they do not have shiny surfaces
like leaded solder joints.

Also, lead-free solder does not flow as well as
leaded solder, so some of the solder pad areas
may remain exposed.

Example of lead-free solder joints.

Example of solder joints with lead.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

4(23)

K750 Working Instructions - electrical

Example of lead-free solder joints.

Example of solder joints with lead.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

5(23)

K750 Working Instructions - electrical

2 BGA equipment reflow profiles

2.1 General

This document contains reflow profile recommendations for mobile phones and
similar products.

They are just general recommendations and considerations have to be taken for
every single product.

The solder paste is secondary but could also affect the parameters.
In this document one alloy is specified:
SnAgCu (Lead free) melting point 217°C

2.2 Temperature measurement

At least 4 probes should be used.
They should be placed on components with the highest and lowest thermal mass.

The probes shall be located in the beginning, in the middle and at the end of the
board/panel.

It is recommended that the probes are soldered on the board, but glue and capton
tape could also be used, if necessary.

At least one probe shall be placed in the air or on top of a component.
These values are strongly depending on the BGA replacement equipment.
Nozzle type will be chosen after the outer size of the actual component.

Make sure the nozzle does not affect any nearby placed components.

These values are recommendations and may have to be changed depending on the
type of equipment.

The maximum temperature for any component must not exceed 250

°C.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

6(23)

K750 Working Instructions - electrical

2.3 Reflow profiles

Sn/Ag/Cu (lead-free)

290

250

Preheat zone

Reflow zone

Cooling zone

260°C
245°C
235°C

200

150

Temperature [ºC]

100

150°C

125°C

50

0

40 80 120 160 200 240 280

Time [Seconds]

Ramp rate < 4°C/sec
Ramp rate cooling zone < 6°C/sec
Time above liquidus 60-150 sec
Minimum temperature 235°C
Maximum temperature 245°C or 260°C* for 10 sec
Bottom heat temperature 125°C-150°C
Total time Appr. 4-7 min

* The higher temperature in case the board has extremely high ∆T.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

7(23)

K750 Working Instructions - electrical

3 Replacement of parts

Equipment

• Dentist hook

• ESD-gloves (cotton gloves)

• ESD-wristband

• Soldering tool

• Hot air soldering station

• BGA replacement equipment

• Pair of tweezers

• Solder cleaning wiper (tin wick)

• Solder paste lead-free (SN 96% Ag 3.5% Cu 0.5%)

Use the soldering tip only for lead-free solder paste!

• Flux, RMA no-clean flux

• Cutting pliers

• Shield fence pliers NTZ 112 537

Caution

Keep all contact surfaces clean of dirt and hand-grease

Instruction

For all the following part replacements, disassemble and assemble the phone as
described in Working Instructions 3/200021-1/FEA 209 544/94.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

8(23)

K750 Working Instructions - electrical

3.1 Backup capacitor

Do not use hot air soldering equipment since the

nearby switch is heat sensitive!

Replace the backup capacitor using a soldering
iron.

3.2 External antenna switch

Replace the external antenna switch.
Use hot air soldering equipment to remove the
switch.

Use BGA repair equipment to resolder the new
switch.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

9(23)

K750 Working Instructions - electrical

3.3 Camera connector BtB 30 pin

Replace the camera connector.
Use hot air equipment to remove the connector.
Use a soldering iron to mount the connector.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

10(23)

K750 Working Instructions - electrical

3.4 LCD connector BtB 20 pin

Replace the LCD connector.
Use hot air equipment to remove the connector.
Use a soldering iron to mount the connector.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

11(23)

K750 Working Instructions - electrical

3.5 Keyboard connector BtB 20 pin

Replace the keyboard connector.
Use hot air equipment to remove the connector.
Use a soldering iron to mount the connector.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

12(23)

K750 Working Instructions - electrical

3.6 SIM reader

Use BGA repair equipment to remove and
replace the SIM reader.

3.7 Battery connector

Use BGA repair equipment to remove and replace
the battery connector.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

13(23)

K750 Working Instructions - electrical

3.8 Memory stick Duo reader

Remove and replace the memory stick reader.
Use a soldering iron.

3.9 IrDA

Remove and replace the IrDA component.
Use a soldering iron or hot air soldering

equipment.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

14(23)

K750 Working Instructions - electrical

3.10 Joystick switch

Use BGA repair equipment to remove and
replace the joystick switch.

3.11 Side key switch

Remove the side key switch.
Use hot air soldering equipment.

Assemble a new side key switch.
Use a soldering iron.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

15(23)

K750 Working Instructions - electrical

3.12 Microphone

Remove and replace the microphone.
Use BGA repair equipment.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

16(23)

K750 Working Instructions - electrical

3.13 Red LED

Remove and replace the red LED.
Use soldering iron equipment.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

17(23)

K750 Working Instructions - electrical

3.14 Diode/ESD protector

Remove and replace the diode/ESD protector
component.

Use BGA repair equipment.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

18(23)

K750 Working Instructions - electrical

3.15 Quartz crystal unit

Remove the shield can lid.
If needed, it is allowed to remove the pick-up area

with cutting pliers.
This pick-up area is only used when the can is
machine mounted and there is no need to put it
back.

Cut the fence according to the white lines in the
picture.

Make sure that the cutting pliers are sharp-

edged to prevent damages to the shield can
fence!

Replace the quartz crystal component.
Use a soldering iron.

Put back a new shield can lid.
Press on all sides of the lid until you hear a “click”
sound.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

19(23)

K750 Working Instructions - electrical

3.16 Prod adapt circuit/ASIC Tjatte 2

Remove the shield can lid.
Cut the fence according to the white line in the

picture.

Make sure that the cutting pliers are sharp-

edged to prevent damages to the shield can
fence!

Form the frame carefully without bending the
shield can fence wall.

Use the shield fence pliers.

Remove the the ASIC Tjatte 2 component.
Use BGA repair equipment.

Replace the ASIC Tjatte 2 component and gently
fold back the fence.

Be very cautious with the shield can fence wall.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

20(23)

K750 Working Instructions - electrical

Gently fold back the fence.
Be very cautious with the shield can fence wall.

Put back a new

shield can lid.
Press on all sides of the lid until you hear a “click”
sound.

3.17 Prod adapt circuit/ASIC Vincenne

Remove the shield can lid.
Remove the ASIC Vincenne component.

Use BGA repair equipment.
Replace the ASIC Vincenne component.

Use BGA repair equipment.

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

21(23)

K750 Working Instructions - electrical

3.18 Mini T-top

To be added later

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

22(23)

K750 Working Instructions - electrical

4 Revision History

Rev. Date Changes / Comments

A 2005-05-13 Initial release
B 2005-05-19 Due to system problem
C 2005-05-19 Due to system problem

3/00021-2/FEA 209 544/94 C
Company Internal

©

Sony Ericsson Mobile Communicat i ons AB

23(23)