Samsung A100 Service Manual Trouble Shooting

7. Trouble Shooting

• Power On Failure.

• SIM Recognition Failure.

• Battery Charging Failure.

• Audio Failure ( Microphone, Speaker )

• Keypad Failure

• Ring Indicator Failure

• Back Light Failure

• Call Failure ( DCS, GSM Rx and Tx part )

7.1 Flow Chart of Troubleshooting

7.1.1 SGH-A100 Power ON

N

‘POWER ON’ does not work

Y

Y

Check the current

consumption more than

100 mA

Download again

N

Y

Check the

Battery Voltage more

than 3.3V

Charge the Battery

N

Y

Check the pin

38 of U401 is more than

3.2 V

Check to the path from CN601 to pin

38 of U400 and keypad

N

Y

U401 pin 28,30

= 2.8V

Change U401

N

Y

END

Y

Check the clock signal

at R116

Check the clock generation circuit

(related to U401 and OSC101)

Check the initial operation

Flow Chart of Troubleshooting

7.1.2 SGH-A100 Initial

N

Initial Failure

Y

Y

Check the “Reset_B”
signal at the pin 2 of

U401 is “High”

Check the U101 (IA)

N

Y

Check the pin 10

of U401 is “High”

Check the U201 (M46)

N

Y

Check the pin 11 of U401

is “High”

Check the U401 (PMIC)

Y

Check the connections and
initialization using Factory

Test Program

END

Y

Check LCD connector CN603,

and resolder bridge

Flow Chart of Troubleshooting

7.1.3 SGH-A100 SIM Part

Phone can’t access SIM card

Y

Check the pin 1, 5 of

CN401. voltage is 2.8V ?

Y

Check the SIM

connector’s CN401

Connection to

SIM card

Y

Check the circuit around U513

(Serial EEPROM) and data stored in it

Y

END

N

N

Check the SIM related circuit of the U401

Resolder CN401

7.1.4 SGH-A100 Charging Part

Abnormal charging part

Y

Flow Chart of Troubleshooting

the pin 9 of CN601

Check

is around 12V

Y

Check the pin 2 of U609

is “Low”

Y

Check the

pin 3 of U607 is more

than 0.5V

Y

Check the

Voltage of pin 10 of

U605 is between 3.2 V

and 4.2 V

Y

N

N

N

N

Replace TA

Check the U201

Resolder R638, R643,L607

Resolder ZD609

END