Diagnostics and troubleshooting phones. Block diagram and principle of operation of a GSM telephone

Type of potential defect

Consequences of a potential defect

Potential causes of defects

Remedy

B, score

A point

E,

score

RPZ, score

Faulty display / sen-keyboard

Does not show

• Damaged LCD display;
• microcircuit malfunction;
• wrong LEDs;
• software failure;
• corrosive damage;
• processor failure.

• Replacing the display;
• software replacement;
• replacement of electronic components;
• replacement of defective items;
• controller replacement;
• contact the service center for diagnostics and repair.

eight

2

one

sixteen

No screen backlight

7

3

2

42

Single color screen

eight

2

one

sixteen

Stripes in the image

eight

2

one

sixteen

Dimmed image

five

four

2

40

Slow reaction to touch

five

6

2

60

It is impossible to enter the menu, dial a number, make a call or answer a call, manage the functions of another phone

eight

one

one

eight

Faulty microphone / speaker

I can not hear the interlocutor / you

• Faulty cable between microphone / speaker and PCB;

• damaged case;
• malfunction chip;
• processor failure;
• frequency generator malfunction;
• receiver and transmitter malfunction;
• filter failure;
• software failure.

• Replacing defective items;
• replacement of electronic components;
• microphone / speaker replacement;
• contact the service center for diagnostics and repair.

eight

four

one

32

You and the other person can hear, but bad

6

four

2

48

Sound Distortion / Noise

6

five

2

60

Missing / missing sound

7

four

one

28

Defective charge

Not charging

• Burnout of PP conductors
• battery failure (sharp drop in capacity);
• charger defective;
• sharp voltage drop;
• damaged charging connector;
• software failure;
• poor contact between the battery and the phone;
• failure of the power amplifier;
• defective voltage regulator;
• broken ceramic plate quartz resonator;
• virus type "Carib" (always turns on Bluetooth).

• Replacing faulty electronic components;
• replacement of components;
• replacement of the charging connector;
• replacement; battery;
• exclusion of voltage drops;
• stabilization of output parameters;
• remove the virus;
• contact the service center for diagnostics and repair.

eight

eight

2

128

Fast discharge

eight

eight

2

128

Phone disconnect

7

6

3

126

Does not show battery indicator

five

2

one

ten

No network / phone does not see the sim card

Barring outgoing calls / messages

• The sim card is not working;
• SIM card expired

- the contacts of the sim-receiver are broken;

• software failure
• damaged antenna;
• Failure of the operational amplifier;
• failure of other electronic components.

• Install another sim card;

• antenna replacement;

• replacement of defective items;
• replacement of electronic components;

• contact the service center for diagnostics and repair.

eight

2

2

32

Barring incoming calls / messages

eight

2

2

32

Cellular signal icon is not displayed.

five

four

one

20

The appearance of the inscription "emergency call"

7

four

one

28

No interaction with computer

Cannot use the phone as a modem

• Software failure;
• damaged USB wires;

• damaged USB connector.

• Software replacement;

• replacement of components;
• Replacing the USB-connector;

• contact the service center for diagnostics and repair.

four

6

3

72

Unable to exchange data

five

five

3

75

Internal memory malfunction

Cannot save files

• Software failure;
• processor failure;
• microcircuit malfunction;
• virus.

• Software replacement;
• CPU replacement;
• replacement of electronic components;
• remove the virus;
• contact the service center for diagnostics and repair.

five

four

3

60

The vibration does not work

No vibrating alert

• Failure of the vibration motor;
• defective loop between the vibration motor and the PP;
• chip malfunction.

• Replacing the vibration motor;
• replacement loop;
• contact the service center for diagnostics and repair.

five

6

one

thirty

No image when taking photos / videos

There is no possibility to photograph / record video

- Damage to the lenses;

- malfunction of the chip.

- the penetration of the electrolyte capacitor to PP.

• Lens replacement;
• contact the service center for diagnostics and repair.

five

3

2

thirty

Blueooth does not work

Cannot find another device / cannot find your device;

• Software failure;
• microcircuit malfunction;
• virus type "Carib".

• Software replacement;
• replacement of electronic components;
• remove the virus;
• contact the service center for diagnostics and repair.

five

6

2

60

Cannot transfer / receive files

five

five

3

75

Does not turn on / off

five

3

2

thirty

Mobile restarts / freezes

Not user friendly

• Software failure;
• failure of the power amplifier (consumes too much current);
• The battery is not working properly.

• Software replacement;
• replacement of electronic components;
• battery replacement.

6

five

3

90