Ericsson T28S, T28SC Troubleshooting Manual

Trouble Shooting Guide, Standard

4/00021-2/FEA 209 544/19 E Approved according to 1776-2/FEA 209 544

Trouble Shooting Guide, Standard

Applicable for T28s and T28sc

Contents

1 Explanations....................................................................................................................2

2 Network Problems...........................................................................................................5

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

4 Audio Problems.............................................................................................................13

5 Display/illumination problems.....................................................................................17

6 Capacity/Charging Problems.......................................................................................21

7 SIM Problems................................................................................................................22

8 Key/Flip Problems.........................................................................................................23

9 Alert Problems...............................................................................................................25

10 Data Communication Problems...................................................................................27

11 Software Problems........................................................................................................27

12 Other Problems.............................................................................................................28

13 Revision History............................................................................................................29

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1 Explanations

For component placing see doc.1078-2/FEA 209 544/19.
Repeated Tests:

When the front has been removed most of the tests can be performed without the front
mounted.

1.1 Abbreviations

B: Crystal.
C: Capacitor.
D: Digital circuit.
F: Over voltage protection.
H: Buzzer, LED and pads for display.
J: Connector.
L: Coil.
N: Analogue circuit, power amplifier at some phones.
R: Resistor.
S: Keyboard pads.
U: BALUN Component that converts a balanced signal to an unbalanced or the other way

around.
V: Transistor, diode.
X: Contact surface on the circuit board.
Z: Filter.

DCIO: DC voltage through the system connector for charging.
GND: Ground.
LED3K: Logical signal that activates the background illumination.
ONSWAn: Voltage from the On/Off key that starts the phone.
RTC: Real Time Clock. The clock that keeps the track of time.
SIMCLK: Signal from the processor used for communication to SIM, clock signal.
SIMDAT: Signal from the processor used for communication t o SIM, data signal.
SIMRST: Signal from the processor used for communication t o SIM, reset signal.
SIMVCC: Feed voltage for SIM.
VBATT: Battery voltage. 3.70 ± 0.05 V
VCORE: DC voltage for the processor and memory at, for instance, stand by mode.

2.50 ± 0.10 V

VDIG: DC voltage for the processor and memory. 2.70 – 2.85 V
VDSPC: DC voltage for the DSP (Digital Signal Processor). 1.80 ± 0.10 V

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VLCD: DC voltage for the display that controls the contrast.
VRAD: DC voltage for the radio part except the synthesiser. 3.80 ±

0.20 V

V380B: DC voltage for the radio part. 3.80 ±

0.20 V

VRTC: DC voltage for the real time clock. 2.35 ±

0.15 V

VVCO: DC voltage for the synthesiser. 3.80 ±

0.10 V

I2C: Communications standard for two-way communication using only 2 wires,

clock and data.

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1.2 Pin Placing

Single diode (PIN diode) Electrolytic capacitor

Double diode or single

transistor

Five pin circuit (usually volt-

age regulator)

Double transistor Eight pin circuit

Ten pin circuit Sixteen pin circuit Crystal

N200 N234 N600

3

5

7

J603

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2 Network Problems

2.1 Find out if the fault is Rx- or Tx-related

Connect the phone to a GSM test instrument and try to get SERV at input signal strength of

-68.5 dBm.
If the phone does not get SERV, go to section 2.2.
If the phone gets SERV, go to section 2.3.

2.2 The phone does not get SERV

Open the phone and check for liquid damage.
Make sure the antenna connector (W100, Fig.2.1) is not incorrectly soldered, mechanically

damaged, dirty or oxidised. Clean, re-solder or replace if needed.
Measure the resistance in the Antenna Connector (Fig. 2.1). Do not press down the antenna

connector. The resistance should be less than 5 ohms.

Fig. 2.1

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Check the solder joints at N200, Z200 and Z201.
Measure the resistance at R220, R221, R222 and R223, (all 0 Ohm).

Replace if incorrect.

Measure the resistance over L200 and L201, (0 Ohm).
Replace if incorrect.

Check that C312 is correctly soldered.

Try to get SERV again with the settings mentioned above.
If the phone gets SERV, go to section 2.3.

If the phone still not get SERV, the fault probably is within the LO part or there are too large
losses in the signal path. It is also possible that the feed voltages are incorrect.

Open the phone.
Power up the board and start it by pressing the On/Off key.
Measure the VRAD voltage at C501, at the pin close to N700 (3.80 V).

If the voltage is incorrect, send the unit on according to the local company directives.

Measure the V380B voltage at C500, at the pin close to C421/C424 (3.80 V).
If the voltage is incorrect, send the unit on according to the local company directives.

Measure the VVCO voltage at pin 5 of N502 (3.80 V).
If the voltage is correct, measure the resistance over R362 (18 kohms) and R363 (100 ohms).

Replace if incorrect.
If both the resistances are correct, go to section 2.2.1.

If the voltage at pin 5 of N502 is incorrect, measure the voltage at pin 1 of N502. It shall be
more than 4.10 V.
If the voltage is correct, replace N502.

If the voltage at pin 1 of N502 is incorrect measure the resistance over R503 (0 ohm), L500 (0
ohm), C503 (> 100 kohms) and C502 (> 100 kohms).
Replace if incorrect.

If all the resistances are correct and the voltage at pin 1 of N502 is 3.70 V replace V500.

If the fault remains, send the unit on according to the local the company directives.

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2.2.1 Check the feed voltages

The VRAD voltage for N234:
Measure the voltage at pin 5 of N234 (3.80 V).

If the voltage is incorrect, measure the resistance of L211 (0 ohm).
If the resistance is incorrect, replace L211.

Measure the voltage at pin 47 of N234 (3.80 V).
If the voltage is incorrect, measure the resistance of R345 (18 ohms).
If the resistance is incorrect, replace R345.

Measure the voltage at pin 62 of N234 (3.80 V).
If the voltage is incorrect, measure the resistance of L370 (0 ohm).
If the resistance is incorrect, replace L370.

The VVCO voltage for D300:
Measure the voltage on R303, at the pin close to R346 (3.80 V).

If the voltage is incorrect, measure the resistance of R303 (18 ohms).
If the resistance is incorrect, replace R303.

Measure the voltage on R334, at the pin close to C333 (3.80 V).
If the voltage is incorrect, measure the resistance of R334 (10 ohms).
If the resistance is incorrect, replace R334.

If the fault remains, send the unit on according to the local company directives.

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2.3 Connect a call at –68.5dBm input signal and power
level 5

If you are able to connect a call, go to section 2.4.
If you are not able to connect a call, measure the resistance from VBATT to ground at the

Battery Connector (Fig.2.2). It should be more than 20 kohms. If the resistance is less, usually
only a few ohms there is probably a short circuit in N400.
If there is a short circuit in N400, send the unit on according to the local company directives.

Fig. 2.2

Open the phone and check for liquid damage.
Make sure the antenna connector (W100, Fig. 2.1) is not incorrectly soldered, mechanically

damaged, dirty or oxidised. Clean, re-solder or replace if needed.
Check the solder joints on N351.
Try to connect a call again.

If you were able to connect a call, go to section 2.4.
If you still are not able to connect a call, send the unit on according to the local company

directives.

2.4 Read the Rx-level while call is connected

Make sure the output power is 31-35 dBm, if the Rx-level value is 40 - 46 steps.
If that is correct there is probably nothing wrong with the phone.

Lower the input signal to –102 dBm and make sure the Rx-level value is 6-12 steps and the
Rx-quality value is 0-2 steps.

If RX-level and Rx-quality is correct, try to run the phone through the test again.
If the phone passes the test but you are not able to connect a call towards the “real” net, make
sure the phone has not been locked out of the system due to theft.

If Rx-level is correct and Rx-quality is high, send the unit on according t o the local company
directives.

If the Rx-level value is too high the phone needs to be calibrated.

If the Rx-level value is less than 38 steps with an input signal of –68.5 dBm or less than 5
steps at an input signal of –102 dBm then the fault is Rx-related.

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Open the phone and check for liquid damage.
Make sure the antenna connector (W100, Fig. 2.1) is not incorrectly soldered, mechanically

damaged, dirty or oxidised. Clean, re-solder or replace if needed.

Check the solder joints at N200, Z200 and Z201.
Measure the resistance over L200 and L201 (0 ohm).

Replace if incorrect.
Remove L204 and measure the resistance from pin 2 of Z200 to ground (>100 kohms).

Usually the resistance is only a few ohms when Z200 is faulty.
If the resistance is incorrect, replace Z200 and mount L204.

If the fault remains, send the unit on according to the local company directives.

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3 On/Off Problems

3.1 Type of fault

Make a general visual inspection of the phone.
Make sure the battery connectors are intact, clean and fully functional.
Measure the resistance from VBATT to ground at the Battery Connector (Fig.3.1). It should

be more than 20 kohms. If the resistance is less, usually only a few ohms there is probably a
short circuit in N400.
If there is a short circuit in N400, send the unit on according to the local company directives.

Fig. 3.1

Make sure there is no liquid damage at the system connector.
Replace if needed.

Insert a fully charged battery and press the On/Off key.
If the phone starts without the On/Off key being pressed, go to section 3.2.
If the phone starts, check the charging function by connecting a charger to the system

connector.
If the charging function is faulty, go to chapter 6 Capacity/Charging Problems.

If the phone starts (lights t he background illumination, asks for SIM/Pin, seeks net…) there is
probably nothing wrong with the phone or the fault is intermittent.

If the phone does not start, insert a dummy battery and keep the On/Off key pressed.
If the phone consumes more than 50mA, go to section 3.3.
If the phone consumes 15-30mA, go to section 3.4.
If the phone consumes less than 15 mA, go to section 3.5.

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3.2 Starts immediately after inserting a battery

Open the phone and check for liquid damage.
Replace the dome foil.

3.3 Consumes more than 50mA

Measure the resistance from VBATT to ground at the battery connector (Fig. 3.1). It should
be more than 20 kohms. If it is less, usually only a few ohms there is probably a short circuit
in N400.
If there is a short circuit in N400, send the unit on according to the local company directives.

Open the phone and check for liquid damage.
Power up the board and press the On/Off key.
Measure the voltage on V500, at the pin close to N700. It should be more than 4.10 V.

If the voltage is 3.7 V replace V500.
Try to flash the signal program into the phone.

If the fault remains, send the unit on according to the local company directives.

3.4 Consumes 15-30mA

Try to program the phone in the flash programmer.
Open the phone and check for liquid damage.
If programming the phone is impossible measure the resistance over R629 (10 kohms).

If the resistance is incorrect, replace R629.
If the resistance over R629 is correct measure the resistance over C615. It should be more

than 40 kohms.
If the resistance is less, replace V607.
If that does not help, replace C615.

If the resistance over C615 is correct, replace D610.
If the fault remains, send the unit on according to the local company directives.

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3.5 Consumes less than 15 mA

3.5.1 Consumes no current

Open the phone and check for liquid damage.
Make sure X100 is not dirty, damaged or incorrectly soldered.

Replace the dome foil.
Power up the board.
Measure the VBATT voltage on C400, at the pin close to C401 (3.70 V).

If the voltage is incorrect, replace X100.
If the voltage at C400 is correct, measure the voltage at pin 2 of V610 (3.65 ± 0.10 V).

If the voltage at pin 2 of V610 is correct, replace V610.
If the voltage at pin 2 of V610 is incorrect, send the unit on according to the local company

directives.
If the fault remains, send the unit on according to the local company directives.

3.5.2 Consumes less than 15 mA

Open the phone and check for liquid damage.
Power up the board and start it by pressing On/Off key.

Measure the VDIG voltage on C703, at the pin close to C834 (2.75 V).
If the voltage is incorrect, check that the resistance from C703, the pin close to C834, to

ground is more than 40 kohms.
If the resistance is correct send the unit on according to the local company directives.

If the resistance from C703 is incorrect, replace C703.

Measure the CORE voltage on C702, at the pin close to R701 (2.50 V).
If the voltage is incorrect measure the resistance from C702, the pin close to R701, to ground.

It should be more than 200 kohms.
If the resistance is correct send the unit on according to the local company directives.

If the resistance from C702 is incorrect, replace C702.

If VDIG and VCORE are correct measure the VDSP voltage (1.80 V) at N740 pin 5.
If the voltage is incorrect, replace N740.
If VDSP is incorrect after the replacement of N740, measure the resistance over C740 (>20
kohms) and R705 (0 ohm). Replace if incorrect.

If both the resistances are correct, send the unit on according to the local company directives.
If VDSP is incorrect after replacement of C740, replace D900.

If the fault remains, send the unit on according to the local company directives.

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4 Audio Problems

4.1 Type of fault

Connect a call from the phone that is to be tested (hereafter called the phone) to a fully
functional phone (hereafter called the reference phone).

Check that the microphone and the earphone of the phone works correctly.
If the phone sounds strange, go to section 4.7.
Connect a hands free unit to the system connector of the phone.
Check the functionality of the hands free by first talking into the reference phone while

listening to the hands free speaker and then t alking into the hands free microphone while
listening to the earphone of the reference phone.

If it is only the earphone, of the phone, that has a little or no sound, go to section 4.2.
If neither the hands free speaker nor the earphone of the phone works, send the unit on

according to the local company directives.
If the sensitivity of the microphone is poor (little or no sound in the reference phone), go to

section 4.3.
If neither the hands free microphone nor the microphone of the phone works, send the unit on

according to the local company directives.
If neither the earphone nor the microphone of the examined phone works, send the unit on

according to the local company directives.
If the hands free microphone does not work, go t o section 4.4.
If the hands free speaker is out of order, go to section 4.5.
If neither the hands free speaker nor the hands free microphone works, go to section 4.6.

4.2 Earphone out of order

Open the phone and check for liquid damage.
Replace the earphone with one you know is functional. Test the phone again.

If the fault remains, make sure that the X831 and X832 connectors are not mechanically
damaged or incorrectly soldered.

If the fault remains, send the unit on according to the local company directives.

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4.3 Microphone out of order

Replace the flip and try again.

Open the phone and check for liquid damage.
Make sure:

• X830 is not mechanically damaged or incorrectly soldered.

• The microphone cable is not mechanical damaged and check specially the connectors.

• The microphone cable is correctly connected to X830 and the flip.

If the fault remains, measure the resistances of R814 (0 ohm), R812, R817, R819 (1 kohm)
and R818 (20 kohms).
If all the resistances are correct, replace C818 and C819.

If the fault remains, send the unit on according to the local company directives.

4.4 Hands free microphone out of order

The fault arises when the audio path is interrupted somewhere between the hands free
microphone (connected through the system connector) and the input of N800. The audio path
is shown in Fig.4.1.

Fig. 4.1

Open the phone and check for liquid damage, especially around the system connector.
Make sure the system connector is not damaged or incorrectly soldered.

Make sure all the components in Fig. 4.1 (R814, R825, R802, R803, R805, R850, C810,
C812, C817, C835 and C850) are mounted at the circuit board.

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Measure the resistances of C810 (>60 kohms), C812 (>1 Mohm), C817 (>1 Mohm), R802
(3.9 kohms), R805 (15 kohms), R803 (1 kohm), R814 (0 ohm), R850 (47 kohms) and C850
(>90 kohms). Replace if incorrect.

If the fault remains, send the unit on according to the local company directives.

4.5 Hands free speaker out of order

The fault arises when the audio path is interrupted somewhere between the output of N800
and the hands free microphone (connected through the system connector). The audio path is
shown in Fig. 4.2.

Fig. 4.2

Open the phone and check for liquid damage, especially around the system connector.

Make sure the system connector is not damaged or incorrectly soldered.
Measure the resistances of R804 (100 kohms), R640 (10 ohms) and C813 (>1 Mohm).

Replace if incorrect.
Measure the resistance from C813, the pin close t o C835, to pin 10 of J602 (10 ohms).

If the resistance is incorrect, replace R640.

If the fault remains, send the unit on according to the local company directives.

4.6 The hands free microphone and speaker out of order

Replace J602.

If the fault remains, send the unit on according to the local company directives.

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4.7 The phone sounds strange

If there is a noise when the illumination is on, replace N750.

If there is distortion or the sound is “chopped”, measure VDIG (2.75 V) at R900 and R902, at
the pins close to D900.
If the voltages are incorrect, measure the resistance of R900 and R902 (10 kohms). Replace if
incorrect.

If the resistances are correct, send the unit on according to the local company directives.

If the voltages are correct, measure the resistance of R904 (1.0 kohms), R914 (0 ohm), R907,
R908 and R909 (100 kohms). Replace if incorrect.

If the resistances are correct, replace D900.

If the fault remains, send the unit on according to the local company directives.

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5 Display/illumination problems

5.1 Display

Insert a fully charged battery into the phone and start it up by pressing the On/Off key.
If the phone does not start, go to chapter 3, On/off problems.
If the display is missing one or more segments, go to section 5.1.1.
If nothing shows in the display, go to section 5.1.2.

5.1.1 Segments are missing

Open the phone and check for liquid damage.
Replace the display.

5.1.2 Nothing shows in the display

Open the phone and check for liquid damage.
Replace the display.

If the fault remains, power up the board and start it up.
Measure the voltage at pin 1 of V611 (3.80 ± 0.20 V).

If the voltage is incorrect, measure the resistance of R639 (10 ohms).
If the resistance is incorrect, replace R639.

If the resistance is correct, replace C639.
If the fault remains, send the unit on according to the local company directives.

Measure the voltage at pin 2 of V608 (5.90 - 6.20 V).
If the voltage is incorrect, measure the resistance of C637 (>100 kohms).
If the resistance is too low, replace C637.

If the resistance of C637 is correct, measure the resistance of R610 (0 ohm).
If the resistance of R610 is incorrect, replace R610.

If the resistance of R610 is correct, replace V608 and V611.
If that does not help, replace C635 and C636.

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Measure the voltages on the display pads (H623).
Pad 1: VLCD 5.90 – 6.20 V
Pad 2: VDIG 2.75 V
Pad 3: I

2

CDAT 2.70 – 2.85 V
Pad 4: Gnd
Pad 5: I

2

CCLK 2.70 – 2.85 V

If I2CDAT or I2CCLK voltage is missing, check the VDIG voltage (2.75 V).
If the VDIG voltage is incorrect, go to chapter 3 (“On/off problems”).

If the VDIG voltage is correct, measure the resistances of R619 (6.8 kohms), R620 (6.8
kohms), R615 (0 ohm) a nd R614 (0 ohm).
If any of the resistances are incorrect, replace the corresponding resistor.

If there is no VLCD voltage, check the resistance from pad 1 of H623 to pin 2 of V608 (0
ohm).
If the resistance is incorrect there is a foil damage, send the unit on according to the local
company directives.

If the fault remains, send the unit on according to the local company directives.

5.2 Background light and LED

Insert a dummy battery and a SIM-card into the phone and start it up by pressing the On/Off
key.
If the background illumination does not light up at start, go to section 5.2.1.

Wait for the phone to get SERV (towards the test instrument or the net).
If the top indicator does not start to flash green when the phone has got SERV, go to section

5.2.2
When the phone has got SERV and the top indicator flash green, reduce the battery voltage to

3.2V. By doing that the top indicator should start to flash red, the battery indicator show an
empty flashing battery and the phone should warn with a beep.
If the battery indicator shows an empty flashing battery but the top indicator does not flash
red, proceed to section 5.2.2.

If none of the above mentioned things happen the phone needs a battery calibration.
Send the unit on according to the local company directives.

5.2.1 Background illumination glows faintly or does not work at all

Use the menu to set the light on (Settings/Profiles/Edit Profiles/Light/On).
Open the phone and check for liquid damage.
Wash around X750 if needed (Fig.5.1).
Replace the illumination panel.

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Fig. 5.1

Power up the board start and it up.
Measure the voltage at pin 10 of N750 (3.7 ± 0.05 V).

If the voltage is incorrect, measure the resistances of L750 (7 ohms), C751 (>1 Mohm) and
the resistance from L750, at the pin close to C667, to VBATT (0 ohms).
If any of the L750 or C751 resistances are incorrect, replace the corresponding component.
If the resistance from L750 to VBATT is incorrect there is a foil damage, send the unit on
according to the local company directives.

If the voltage at pin 10 of N750 is correct, measure the voltage at pin 5 of N750 (2.70–

2.85V).
If the voltage at pin 5 of N750 is correct, replace C752.

If the voltage at pin 5 of N750 is incorrect, measure the resistance from C703, at the pin close
to C834, to pin 5 of N750 (0 ohm).
If the resistance is incorrect there is a foil damage, send the unit on according to the local
company directives.

Measure the resistance of R750 (18 kohms at board revision up to R1D, 22 kohms at board
revision R1E and later).
If the resistance is incorrect, replace R750.

If the resistance is correct, replace N750.

If the fault remains, send the unit on according to the local company directives.

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5.2.2 Red or green top indicator out of order

Open the phone and check for liquid damage.
Make sure the double LED (H650) is not incorrectly soldered.
If the solder joint is correct, power up the board and start it by pressing the ON/Off key.
Measure the voltage at pin 1 of H650 (2.70 – 2.85 V).

If the voltage is correct, replace H650. Assemble the phone and test as described in section

5.2.
If the voltage at pin 1 of H650 is incorrect, measure the resistance of R646 (220 ohms).

If the resistance is incorrect, replace R646.
If the resistance is correct there is a foil damage, send the unit on according to the local

company directives.

If the fault remains, send the unit on according to the local company directives.

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6 Capacity/Charging Problems

Make a visual check of the battery connector and the system connector. Replace them if
needed.

Insert a charged battery into the phone and start it up by pressing the On/Off key. Turn the
phone of and connect a charger to the system connector to make sure the fault remains.

Open the phone and check for liquid damage.

Measure the resistance of R710 (0.1 ohm).
If the resistance is incorrect, replace R710.

If the resistance of R710 is correct, measure the resistance of R711 (0 ohm).
If the resistance is incorrect, replace R711.

If the resistance of R711 is correct, replace V710.

If the fault remains, send the unit on according to the local company directives.

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7 SIM Problems

7.1 What is SIM-fault

Insert a functional SIM-card and a charged battery into the phone.
If “Wrong card” or “Insert correct card” is displayed on the display when starting the

phone it means that the phone is SIM-locked.

NOTE! If the phone shall be SIM-locked, make sure that a correct SIM-card is used.

If the fault remains, send the unit on according to the local company directives.
If the phone displays “Phone lock” on the display it means that the customer has locked the

phone with a personal code. It will be unlocked in the reset program. (Available in the Built
Swap process)

If “PIN:” or “Enter PIN:” is displayed, it means that the SIM-card has been locked with a
personal code.

It is only SIM-fault if “Insert card” is displayed.

7.2 Type of fault

Open the phone and check for liquid damage.

Replace J603.
Measure the resistance from pin 1 to pin 5 of J603 (>1 Mohm).

If the resistance is incorrect, replace C734, C736.
Measure the resistance of R734 (10 kohms).

If the resistance is incorrect, replace R734.
Measure the resistance from R733, at the pin close to R731, to pin 1 of J603 (15 kohms).

If the resistance is incorrect, replace R730.
Measure the resistance from R733, the pin close t o R731, to pin 7 of J603 (33 ohms).

If the resistance is incorrect, replace R733.
Measure the resistance from R731, at the pin close to R730, to pin 2 of J603 (33 ohms).

If the resistance is incorrect, replace R731.
Measure the resistance from R732, at the pin close to R731, to pin 3 of J603 (0 ohm).

If the resistance is incorrect, replace R732.

Replace C735.

If the fault remains, send the unit on according to the local company directives.

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8 Key/Flip Problems

8.1 Type of keyboard and flip fault

Insert a fully charged battery and a SIM-card into the phone. Start it up by pressing the
On/Off key.

If the phone does not start at all, go to chapter 3 (“On/off problems”).
If the phone starts but none of the keys are functional, go to section 8.2.

Press all the keys (including the volume key) to verify which of the keys that are functional.
The verification is most easily done this way:

1. Go to “Menu/Settings/Sounds&Alerts/Key sound” and choose “Click”.

2. Press the 1, 2, 3…*, 0, # keys. A clicking sound should be heard and the corresponding

symbol should appear in the display at every key pressed. Then press the “Yes”, “No”,
“clr”, “<” and “>” keys. When pressing the “Yes” key the phone should try to connect a
call and when pressing the “No” key should make it disconnect the call. The “clr” key
makes the phone erase the symbols in the display one by one while the “<” and “>” keys
make you skim through the menu.

3. Move the volume button down. A Status menu shows on the display. Press the volume

button down and up some times to look trough t he menu. Check that the button springs
back.

If only t he volume key is faulty, go to section 8.3.

4. With the telephone ON, wait until the background light has gone off, then close or open

the Flip. The light should now be turned on if the light is set to automatic in the Settings

menu.
If not, go to section 8.4.
The flip does not stay in closed position, go to section 8.4.

8.2 One or more of the keys out of order

Open the phone and check for liquid damage.
Remove the dome foil, clean the pads and mount a new dome foil.
Test the keys as described in section 8.1 again.

If the fault remains, send the unit on according to the local company directives.

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8.3 Volume key out of order

Replace J820.

If the fault remains, send the unit on according to the local company directives.

8.4 Flip function out of order

The flip does not stay in closed position, replace the front and flip.

The active flip function is out of order.
Open the phone and check for liquid damage.
Measure the voltage at pin 1 of N600 (2.70 – 2.85 V).

If the voltage is incorrect, send the unit on according to the local company directives.
If the voltage at pin 1 of N600 is correct, measure the voltage at pin 2 of V630 (3.70

±

0.05V).

If the voltage at pin 2 of V630 is incorrect there is a foil damage, send the unit on according
to the local company directives.

If the voltage at pin 2 of V630 is correct, replace V630 and V631.
If that does not help, replace N600.

Measure the resistance over R685 (100 kohms), i f incorrect replace it.

If the fault remains, send the unit on according to the local company directives.

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9 Alert Problems

9.1 Type of fault

Insert a dummy battery and a SIM-card into the phone and start it up by pressing the On/Off
key. Wait for the phone to get SERV (towards the test instrument or the net).

If the phone does not beep at start-up, use the menu to increase the ring volume (not from full
to “step”, as that does not generate any sound).
If the sound is faint or there is no sound at all, go to section 9.2.

Use the menu to set the vibrator to ON mode. If the phone does not vibrate when the settings
are stored, go to section 9.4.

9.2 Buzzer faint or dead

Open the phone and check for liquid damage.
Make sure the buzzer (H600) is not incorrectly soldered.

If the solder joints are correct, replace H600.
Assemble the phone and try again as described in section 9.1.

Open the phone, power up the board and start it by pressing the On/Off key.
Measure the voltage at pin 3 of H600 (3.70 ±

0.05 V).

If the voltage is incorrect, replace R603.
If that does not help there is a foil damage, send the unit on according to the local company
directives.

Measure the resistance of R651 (1 kohm).
If the resistance is incorrect, replace R651.

If the resistance is correct, replace V606.
If that does not help, replace V605.

If the fault remains, send the unit on according to the local company directives.

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9.3 Vibrator does not work

Open the phone and check for liquid damage.

Fig.9.1

Make sure:

• There is no cable breakage.

• The connector is not damaged or incorrectly mounted.

• X680 is not dirty or damaged.

Power up the board and start it by pressing the ON/Off key.
Measure the voltage at pin 2 of V621 (3.70 ±

0.05 V).

If the voltage is incorrect there is a foil damage, send the unit on according to the local
company directives.

Measure the voltage at pin 3 of V623 (3.65 ±

0.05 V).

If the voltage is incorrect, measure the resistance of R683 (100 kohms).
If the resistance is incorrect, replace R683.

If the voltage at pin 3 of V621 is correct, replace V621 and V623. Make sure R627, R628 and
C681 are mounted and correctly soldered. Measure the resistance of R682 (1 kohm).
If the resistance is incorrect, replace R682.

If the fault remains, send the unit on according to the local company directives.

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10 Data Communication Problems

Make a visual check of the system connector. Replace it if needed.
Measure the resistance over R634 (220 ohms).

If the resistance is incorrect, replace R634.
Measure the resistance over R625 (220 ohms).

If the resistance is incorrect, replace R625.
Measure the resistance over R626 (10 kohms).

If the resistance is incorrect, replace R626.
Measure the resistance over C657 (>3 Mohms).

If the resistance is incorrect, replace C657.
Measure the resistance over R636 (470 ohms).

If the resistance is incorrect, replace R636.
Measure the resistance over R622 (470 ohms).

If the resistance is incorrect, replace R622.
Measure the resistance over R650 (100 kohms).

If the resistance is incorrect, replace R650.
Measure the resistance over C656 (100 kohms).

If the resistance is incorrect, replace C656.

If the fault remains, send the unit on according to the local company directives.

11 Software Problems

11.1 Characters in Phone Book

If the customer has complained about the characters in the Phone Book, make a reset of the
phone.

If the fault remains, send the unit on according to the local company directives.

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12 Other Problems

12.1 RTC

12.1.1 Figure out the fault

Start the phone with a SIM-card and a fully charged battery. Set the correct time. Remove the
battery and re-insert it after one minute.

If the phone clock says 00:00, go to section 12.1.2.
Compare to the correct time.
If the clock is halted or speeding, go to section 12.1.3.

12.1.2 The clock says 00:00 after re-inserting the battery

Open the phone and check for liquid damage.
Make sure that t he backup capacitor (C720) and R700 are correctly soldered. Measure the

resistance of R700 (3.3 kohms).
If all are correct, replace C720.

If the resistance of R700 is incorrect replace it.

Assemble the phone, start it up and set the correct time. Wait a few minutes for the backup
capacitor to charge. Remove the battery and re-insert it after a minute. Make sure the fault has
been fixed (the backup capacitor needs 20 minutes of charging before reaching full capacity).
Compare to the correct time. If the clock is halted or speeding, go to section 12.1.3.

If the fault remains, send the unit on according to the local company directives.

12.1.3 The clock is halted or speeding

Open the phone and check the solder joints on B600.
If they are correct, replace B600.
If that does not help, replace C690 and C691.

Assemble the phone and compare to the correct time.

If the fault remains, send the unit on according to the local company directives.

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13 Revision History

Rev. Date Changes / Comments

C 1999-12-15 Convert from FrameMaker to Word.

Division into chapters/ chapter headings changed.
Pictures removed.
Component placement reference added in chapter 1.
Pin placement – N200 changed and N600 added.
Action added in chapter 2.2, chapter 2.3, chapter 3.1, chapter 3.3,
chapter 4.3 and chapter 5.1.2.
Action removed in chapter 7.2
Chapter 8.1 and chapter 8.4 changed

D 2000-03-10 Documents title and layout changed.

Pin placing - J603 added.
Action added in chapter 5.2.
Action changed in chapter 5.2.2.
Voltage tolerances added in chapter 1.1.

E 2000-03-28 Action added in chapter 3.4 and 3.5.2.

Value on R750 changed on board revision R1D in chapter 5.2.1.
Chapter 4.7 added.
Chapter 5.2.1. changed.