Samsung SGH-S300 Troubleshooting

6. S GH -S3 00 Flow Chart o f Troublesho oti ng and Circuit Di agram s

1.Baseband

1. Power ON

'Power On' does not

work

Check the current

consumtion more than

100mA

YES

Check the

Vbat(battery+O)

Voltage more than

3.3V

YES

Check the pin

15 of U100 is more

than 2.8V

YES

U100 pin 46,39

= 2.8V

NO

NO

NO

NO

Downloader again

Charge the Battery

Check U100 and C113

Check U114 and C116

YES

U100 pin 13

= 1.8V

YES

Check the clock signal

at

pin4 of U801

Freq=13MHz ?

Vrms°√300mV ?

Vpp is around

900mVpp

YES

'Power On' does not

work

END

NO

NO

Check U112

Check the clock generation circuit

(related to OSC801 and U801)

SAMSUNG Proprietary-Contents may change without notice

6-1

SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams

2. Initial

Ini tial Failure

Check the signal at the

pin 28 of U100 is

"High" when the phone

is boot on

YES

Check the pi n 22 of

U100 is "High"

YES

Check the pin 4 of

OSC801 is around 2. 8V

YES

Chec k and resolder LCD connector CN200

if there is solder bridhe between the pins

YES

NO

NO

NO

Chec k U100

Chec k the U700

Check the soldered status of

OSC801, R803, U100

3. Sim Part

END

Phone c an't access SIM card

Check the pin 1 of CN100.

Voltage = 3V?

YES

Check the SIM

connector's (CN100)

connector's to SIM card

YES

Check the circuit around CN100 input

circuitry

YES

Check the ci rcuit around U601 output

and voltage supply c ircuitry

NO

NO

NO

NO

Check the ci rcuit related to

resolder or change CN100

Check the related ci rcuit of

Check the related ci rcuit of

U100

CN100

U601 and U100

YES

END

SAMSUNG Proprietary-Contents may change without notice

6-2

4. Charging Part

Abnormal c ha rging part

SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams

Check the pin 17,18 of
CN302 VEXT is > 4V?

YES

Check the pin 2 of U103

is "LOW"?

YES

Check the pin 3 of Q101

is "LOW"?

YES

Check the pin 5 of U102

is "3.2~4.2"?

YES

Check if ICHRG is 1V

(during charging) and

around 180mV(full

chargi ng)

YES

NO

NO

NO

NO

NO

Chec k U100

Chec k the U700

Chec k the Q101

Chec k the U102

Resolder or change R 111

END

SAMSUNG Proprietary-Contents may change without notice

6-3

SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams

5. Microphone Part

Microphone does not w ork

6. Speaker Part

Spea ker does not w ork

Check the assembled

status of microphone.

YES

Chec k the reference

voltage on mi c path

C418 =2. 5V

YES

Is mic rophone ok?

YES

END

NO

NO

NO

Reassembl age microphone

resolder or change

C400,R 428,R 409,R 405,R406)

Chec k U700

Check the connection

status spk to CN200

YES

Check the PIN 1 of

U402 = 'High' ?

YES

Check U700, R 201, R202

YES

Is s peaker ok?

YES

END

SAMSUNG Proprietary-Contents may change without notice

NO

NO

NO

NO

Resol der and check the board

to board connector

Chec k U601

Cha nge or resolder

U700, R201, R202

Change Speaker

6-4

7. Back Light

Check the soldered status of EL pad

SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams

Backlight does not work

YES

Backlight "ON" mode in

the meue?

YES

Check the PIN 3 of

200-1 = 2.8V?

YES

Chec k the connection

from CN202 to LCD

Module

YES

LCD bac klight on?

YES

END

NO

NO

NO

NO

Sel ect backlight "ON" mode

Chec k the U601

Replace FPCB CONNECTOR

Cha nge L CD Module

SAMSUNG Proprietary-Contents may change without notice

6-5

SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams

8.Alert Tone

Abnormal Al ert tone

Alert tone On by pushing the key

*#0289#

Check the P IN 17, 18 of

CN200-1

Is there alert w ave?

YES

Check the connection
from CN200-1 to LCD

Module

YES

Alert is ok?

YES

END

NO

NO

NO

Check the ci rcuit related to

U400, U401

Change Speaker

Cha nge L CD Module

SAMSUNG Proprietary-Contents may change without notice

6-6

2.RF

1. GSM Receiver

CONTINUOS R X ON

RF INPUT : 62CH

Cell power : -50dBm

SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams

NORMAL CONDITION

catch the channel?

YES

F1002 CHECK

pin13 ≥ -65dBm?

YES

F1002 CHECK

pin1,2 ≥ -65dBm?

YES

U901 CHECK

pin21,22 ≥ -65dBm?

YES

U901

pin 12, 13 ≥

20dBm?

YES YES

NO

NO

C1012,L1015,C1002 contact?

NO

resolder or change

NO

res ol der or change

NO

C1007,L1001,C1011

resolder or change

U902 CHECK

pin5,25, 28 : 3V?

U902 CHECK

pin 7 : 13MHz?

CHECK

CN1001

F1002

NO

NO NO

U100, P IN39, C116

chec k or res ol der

OSC801 CHECK
pin 3 : 13MHz ?
V p-p : 950mV?

NO

OSC801 CHECK

pin 4 : clean

3V?

U901 CHECK

pin14,23,26,32 :

3V?

YES

U901 Pin3,4

Vp-p:240mV ?

YES

U901 Pin1,2

Vp-p:250mV ?

YES

U900

Pin2,3,4,5

Vp-p:100mV ?

NO

L1006,C1015,C1019

resolder or change

NO

NO

NO

YES

YES YES

U902

change or resolder

U100, P IN 46, C114

res ol der or change

U900 CHECK

pi n 6,20 : 2.8V?

YES

U900

res ol der or change

NO

C808, R805

resol der

YES

OSC801

change

SAMSUNG Proprietary-Contents may change without notice

6-7