Samsung SGH-D428 Service Manual

GSM TELEPHONE

SGH-D428

GSM TELEPHONE

CONTENTS

1. Specification

2. Flow Chart of Troubleshooting

3. Exploded Views and Parts List

4. Electrical Parts List

5. Block Diagrams

6. PCB Diagrams

This Service Manual is a property of Samsung Electronics Co.,Ltd.
Any unauthorized use of Manual can be punished under applicable
International and/or domestic law.

ⓒ

Samsung Electronics Co.,Ltd. Dec. 2004
Printed in Korea.

Code No.: GH68-06337A

BASIC.

1. SGH-D428 Specification

1. GSM General Specification

GSM900
Phase 1

Freq. Band[MHz]

Uplink/Downlink

ARFCN range 1~124

Tx/Rx spacing 45MHz 45MHz 95MHz 80MHz

Mod. Bit rate/

Bit Period

Time Slot

Period/Frame

Period

Modulation 0.3GMSK 0.3GMSK 0.3GMSK 0.3GMSK

MS Power 33dBm~13dBm 33dBm~5dBm 30dBm~0dBm 30dBm~0dBm

890~915
935~960

270.833kbps

3.692us

576.9us

4.615ms

EGSM 900

Phase 2

880~915
925~960

0~124 &

975~1023

270.833kbps

3.692us

576.9us

4.615ms

DCS1800

Phase 1

1710~1785
1805~1880

512~885 512~810

270.833kbps

3.692us

576.9us

4.615ms

PCS1900

1850~1910
1930~1990

270.833kbps

3.692us

576.9us

4.615ms

Power Class 5pcl ~ 15pcl 5pcl ~ 19pcl 0pcl ~ 15pcl 0pcl ~ 15pcl

Sensitivity -102dBm -102dBm -100dBm -100dBm

TDMA Mux 8 8 8 8

Cell Radius 35Km 35Km 2Km -

1-1

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SGH-D428 Specification

2. GSM TX power class

TX Power

control level

5 33±2dBm

6 31±2dBm

7 29±2dBm

8 27±2dBm

9 25±2dBm

10 23±2dBm

11 21±2dBm

12 19±2dBm

13 17±2dBm

14 15±2dBm

15 13±2dBm

GSM900

TX Power

control level

0 30±3dBm

1 28±3dBm

2 26±3dBm

3 24±3dBm

4 22±3dBm

5 20±3dBm

6 18±3dBm

7 16±3dBm

8 14±3dBm

9 12±4dBm

10 10±4dBm

DCS1800

TX Power

control level

0 30±3dBm

1 28±3dBm

2 26±3dBm

3 24±3dBm

4 22±3dBm

5 20±3dBm

6 18±3dBm

7 16±3dBm

8 14±3dBm

9 12±4dBm

10 10±4dBm

PCS1900

16 11±2dBm

17 9±2dBm

18 7±2dBm

19 5±2dBm

11 8±4dBm

12 6±4dBm

13 4±4dBm

14 2±5dBm

15 0±5dBm

11 8±4dBm

12 6±4dBm

13 4±4dBm

14 2±5dBm

15 0±5dBm

1-2

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2. SGH-D428 Flow Chart of Troubleshooting

1.Baseband

1. Power ON

'Power On' does not work

Yes

Check the current

consumption more

than 100mA

Yes

Check the VBAT
more than 3.3V

Yes

Check the pin
11 of U102 is

more than 2.8V

Yes

U102 pin 33,39

=2.8V

Yes

No

No

No

No

Download again

Charge the Battery

Check the C117

U102 pin 9

=1.8V

Yes

No

Check U102 and C116

Check the clock

signal at pin4 of

OSC801

Freq=13MHz ?

Vrms≥300mV ?

Vpp is around

900mVpp ?

Yes

Check the initial operation

END

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No

Check the clock generation

circuit

2-1

SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams

2. Initial

Initial Failure

Yes

Check the signal at the

pin 21 of U102 is

"High" when the phone

is boot on

Yes

Checkthekeymetrix

of the U601

Yes

Check the VCCD,VCC_1.8A

Check LCD connector CN201 in the main

PBA and the FPCB connector

of U601

Yes

Check the vccd of

U601 is around 2.8V

Yes

Yes

END

No

No

No

No

Check the pin 46,20 and Q103

Check the key program and

the key pcb

Check the soldered status of U601,

OSC601

Check the soldered status of

U601,osc601

3. Sim Part

Phone can't access SIM card

Yes

Check the pin 1 of

CN101. voltage 3V ?

Yes

Check the SIM

connector's (CN101)

connection to SIM

card

Yes

Check the circuit around CN101

Check the circuit around U601

and vlotage supply circuitry

input

circuitry

Yes

output

Yes

END

2-2

No

No

No

No

Check the circuit related to

U102

Resolder or change CN101

Check the related circuit of

CN101

Check the related circuit of

U601 and U102

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4. Charging Part

Abnormal charging part

SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams

Yes

Check the pin 17, 18

of CN300 is

TA_VEXT>4?

Yes

Check the pin 2 of

U101 is "low"?

Yes

Check the pin 3 of

Q101 is "low"?

Yes

Check the pin 5 of

U101 is "3.2~4.2V"?

Yes

Check the ICHRG is

1V(during charging)

and around

180mV(full charging)?

No

No

No

No

No

Replace TA,Check CN300-1

Check the U101

Check the Q101

Check the U101

Resolder or change R111

Yes

END

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SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams

5. Microphone Part

Microphone does not work

Yes

6. Speaker Part

Speaker does not work

check the soldered

status of microphone.

Yes

Check the reference
voltage on mic path

C411≒2.5 V

Yes

Is microphone ok?

Yes

END

No

No

No

Resolder microphone

Resolder or change

R413,C420,R414,C410,R411,R40

8

Check U701

Yes

Check the FPCB from

CN201 to CN11

Yes

Check the PIN 4 of

U401='High' ?

Yes

Is speaker ok?

Yes

Is speaker ok?

Yes

END

No

No

No

No

Retry connection the FPCB from

Check componants near the U402

CN201 to CN11

Check U401 and the audio

path of U701

and control line of U402

Change Speaker

2-4

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2.RF

1. EGSM RX

NORMAL CONDITION

catch the channel?

pin13≥-65dBm ?

pin1, 2≥-65dBm ?

YES

F1001 CHECK

YES

F1001 CHECK

YES

NO

NO

NO

SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams

CONTINUOUS RX ON

RF INPUT : 62CH

CHECK

ANT1001,L1002 contact ?

C1003, C1006

resolder or change

F1001

resolder or change

AMP : -50dBm

U1002 CHECK

pin20,21≥-65dBm ?

YES

U902

pin 26,32: 2.8V ?

YES

U903 CHECK

pin 7 : 13MHz ?

Vp-p : 950mV?

YES

U902

pin1,2,5,6 Vp-p

:120mV?

YES

U702,R701

resolder or change

NO

NO

NO

NO

U102 pin39, C112

change or resolder

OSC801

change or resolder

resolder or change

C1005,C1006,L1003

resolder or change

U902

2-5

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SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams

2. DCS RX

NORMAL CONDITION

catch the channel?

YES

NO

CHECK

ANT1001,L1002 contact ?

CONTINUOUS RX ON

RF INPUT : 698CH

AMP : -50dBm

F1001 CHECK

pin13≥-65dBm ?

YES

F1001 CHECK

pin3, 4≥-65dBm ?

YES

U902 CHECK

pin21,22≥-65dBm ?

YES

U902

pin 26,32: 2.8V ?

YES

U903 CHECK

pin 7 : 13MHz ?

Vp-p : 950mV?

YES

U902

pin1,2,5,6 Vp-p

:120mV?

NO

NO

NO

NO

NO

NO

U102 pin39, C112

change or resolder

change or resolder

resolder or change

C1008,C1009

resolder or change

F1001

resolder or change

C1008,C1009,L1004

resolder or change

OSC801

U902

YES

U703,R704

resolder or change

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3. PCS RX

NORMAL CONDITION

catch the channel?

YES

F1001 CHECK

pin13≥-65dBm ?

YES

F1001,F1002 CHECK

pin6≥-65dBm ?

YES

NO

NO

NO

SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams

CONTINUOUS RX ON

RF INPUT : 660CH

CHECK

ANT1001,L1002 contact ?

C1012, F1013

resolder or change

F1001,F1002,R1011

resolder or change

AMP : -50dBm

U902 CHECK

pin16, 17≥-65dBm ?

YES

U902

pin 26,32: 2.8V ?

YES

U903 CHECK

pin 7 : 13MHz ?

Vp-p : 950mV?

YES

U902

pin1,2,5,6 Vp-p

:120mV?

YES

U704,R705

resolder or change

NO

NO

NO

NO

U102 pin39, C112

change or resolder

change or resolder

C1012,F1002,C1013,R1011,L1006

resolder or change

OSC801

U902

resolder or change

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SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams

4. EGSM TX

F1001 pin 12 :

about 2~3

F1003, C1003

check&change

NO

YES

U1001

pin 5 : 3.7 V?

YES

U1001

pin 6 : 1.2V ?

U1001 pin7

about : -5dBm ?

NO

NO

YES

YES

F1001

pin13:2.8V?

U1001 pin9 :

about 4~5dBm?

F1001,C1015

check & change

NO

BATTERY, U102

check & change

NO

YES

YES

U701

check

NO

U701,U702

check & change

CONTINUS TX ON CONDITION

TX POWER DAC: 550 CODE APPLIED

CH : 62

RBW : 100KHz

VBW : 100KHz

SPAN : 10MHz

REF LEV. : 10dBm

ATT. : 20dB

U102 pin39,C112

change or resolder

U1001

pin 3 : 3V?

YES

U1001

change or resolder

NO

change or resolder

NO

U701

check

U902

pin14,26,32 : 2.

8V ?

NO

U701

YES

U903

pin7 : 13MHz ?

Vp-p : 950mV?

U902

pin1,2,4,5:100m

U902

change or resolder

YES

YES

NO

change or resolder

OSC801

2-8

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