Samsung SCH-A302 User manual

SERVICE
Cellular Phone
SCH-A302
Manual
Cellular Phone CONTENTS
1. Specification
2. Trouble Shooting
3. Tune-up Procedure &
Test Procedure list
4. Frequency Synthesizer Circuit &
Spurious Radiation
Suppression Circuit
5. NAM Programming
6. Electrical Parts List
7. Exploded Views & Parts List
8. Block Diagram
9. PCB Diagrams
10. Circuit Description &
Circuit Diagrams

©Samsung Electronics Co.,Ltd. December. 2001
Pinted in Korea.
Code No.: GH68-02488A
BASIC.
ELECTRONICS

1. SCH-A302 Specification (REF TIA/EIA/IS-137-A-1)
1. GENERAL
SAMSUNG Proprietary-Contents may change without notice
1-1
ITEM CDMA
TX Freq. Range 824 ~ 849 MHz
RX Freq. Range 869 ~ 894 MHz
Channel Bandwidth 1.23 MHz
Channel Spacing 30 kHz
Number of Channels 20 FA
Duplex Separation 45 MHz
In/Output Impedance 50 Ω
TX Intermediate Freq. 130.38 MHz
RX Intermediate Freq. 85.38 MHz
TX Local Freq. 1st(FTX + 130.38 MHz)
2nd(260.76 MHz)
RX Local Freq. 1st(FTX + 210.38 MHz)
2nd(170.76 MHz)
TCXO freq. 19.68 MHz
Freq. Stability (FRX - 45 MHz) ± 350 Hz
Operating Temperature -30 °C ~ +60 °C
Supply Voltage + 3.8 V
SMALL : 81 x 42 x 21 mm 84 g
Size and Weight MIDDLE : 81 x 42 x 22 mm 87 g
LARGE : 81 x 42 x 25 mm 98 g

SAMSUNG Proprietary-Contents may change without notice
1-2
SCH-A302 Specification
2. 800 MHz CDMA
2-1. GENERAL
TX Freq. Range 824 ~ 849 MHz
RX Freq. Range 869 ~ 894 MHz
Channel Bandwidth 1.23 MHz
Channel Spacing 30 kHz
Number of Channels 20 FA
Duplex Separation 45 MHz
In/Output Impedance 50 Ω
TX Intermediate Frequency 130.38 MHz
RX Intermediate Frequency 85.38 MHz
TX Local Frequency 1st (FTX + 130.38 MHz)
2nd (260.76 MHz)
RX Local Frequency 1st (FRX + 85.38 MHz)
2nd (170.76 MHz)
TCXO Frequency 19.68 MHz
Freq. Stability (FRX - 45 MHz) ± 150 Hz
Operating Temperature -30 °C ~ +60 °C
Supply Voltage + 3.8 V
2-2. TRANSMITTER
Waveform Quality 0.944 or more
Open Loop Power Control
-25 dBm -57.5 dBm ~ -38.5 dBm
-65 dBm -17.5 dBm ~ +1.5 dBm
-104 dBm +18.0 dBm ~ +30.0 dBm
Minimum TX Power Control Below -50 dBm
Closed Loop TX Power Control Range ± 24 dB
Maximum RF Output Power 200 mW (+24.5 dBm)
Occupied Band Width 1.32 MHz
Conducted Spurious Emission @900 kHz -42 dBc / 30 kHz
@1.25 MHz -54 dBc / 30 kHz

SAMSUNG Proprietary-Contents may change without notice
1-3
SCH-A302 Specification
2-3. RECEIVER
Rx Sensitivity and Dynamic Range -104 dBm, FER=0.5 % or less
-25 dBm, FER=0.5 % or less
Conducted Spurious Emission
869 ~ 894 MHz < -81 dBm
824 ~ 849 MHz < -61 dBm
All other Frequencies < -47 dBm
Single Tone Desensitization
Rx Power level -101 dBm
Tone Power level -30 dBm Lower than 1 %
Tone Offset from Carrier ± 900 kHz
Intermoculation Spurious Response Attenuation
Tone 1 offset from carrier = ± 900 kHz
Tone 2 offset from carrier = ± 1,700 kHz
-Test 1, 2
Rx power = -101 dBm
Tone 1 power = -43 dBm
Tone 2 power = -43 dBm
-Test 3, 4 Lower than 1 %
Rx power = -90 dBm
Tone 1 power = -32 dBm
Tone 2 power = -32 dBm
-Test 5, 6
Rx power = -79 dBm
Tone 1 power = -21 dBm
Tone 2 power = -21 dBm

SAMSUNG Proprietary-Contents may change without notice
2-1
2. SCH-A302 Trouble Shooting
1. Logic Section
1-1. No Power
Y
U501 pin38 Input=HIGH Check Q507, Q509 and its
neighboring circuits
N
Y
U501 pin6 & pin10
output=2.8 V?
Check U501 pin6 & pin10 and its
neighboring circuits
N
Y
U501 pin39
Input=HIGH? Check R536 and its neighboring
circuits
N
END
Press PWR button

SAMSUNG Proprietary-Contents may change without notice
2-2
SCH-A302 Trouble Shooting
1-2. Abnormal Initial Operation
Y
TCXO CLK
applied to U609 pina17/U404
pin7?
Check VCTCXO output.
Replace if required.
N
Y
TCXO CLK
signal outputted from OSC401
pin3?
Check OSC401 and its neighboring
circuits. Replace if required.
N
Y
TCXO CL
signal outputted from OSC401
pin4?
Check OSC401 and its neighvoring
circuits. Replace if required.
N
Y
TCXO CL
signal outputted from OSC402
pin4?
Check OSC402 and its neighvoring
circuits. Replace if required.
N
Y
LED on? Check the LED and its neighboring
circuits. Replace if required.
N
Y
Normal initial
display on LCD?
Check the LCD pins and its
neighboring circuits. Replace if
required.
N
Press PWR Key
END

SAMSUNG Proprietary-Contents may change without notice
2-3
SCH-A302 Trouble Shooting
1-3. Abnormal Backlight Operation
Y
‘L’ level outputted
from U501 pin1? Check U501 pin1 and its neighboring
circuits. Replace if required.
N
Y
‘L’ level outputted
from U501 pin2?
Check U501 pin1 and its neighboring
circuits. Replace if required.
N
Press any button on the phone
Backlight LED on
1-4. Abnormal Key Data Input
Y
Scanning signals
outputted from U609 pins C2,
A3, E4, D3, C1?
Check keypad dom switch.
Replace if required.
N
Check initial status
END

SAMSUNG Proprietary-Contents may change without notice
2-4
SCH-A302 Trouble Shooting
1-5. Abnormal Keytone
Y
CLK wavefrom outputted
from U609 pin L16 & pin M17?
Check the U609 pin and its
neighboring circuits.
Replace if required.
N
Y
CLK waveform outputted
from CON500 pin 5?
Resolder CON500 and its neighboring
circuits. Replace if required.
N
Y
Key tone waveform
applied to C561? Check C631. Replace if required.
N
Y
Normal Keytone? Replace the SPK assembly.
N
Abnormal Keytone
END

SAMSUNG Proprietary-Contents may change without notice
2-5
SCH-A302 Trouble Shooting
1-6. Abnormal Alert Tone
Y
CLK waveform outputted
from U609 pin C14.
Check the U609 pin and its
neighboring circuits. Replace if
required.
N
Y
CLK waveform applied to
Q511 Base?
Check R552, Q511 and its neighboring
circuits. Replace if required.
N
Y
Is the buzzer connection
correct? Connect the buzzer correctly.
N
Abnormal Keytone
Check the buzzer and
replace if required.
2. Transmitter Section
Abormal transmitter section
Y
Turn On Max PWR
N
Check U402 local level.
Y
Check U204 TX RFT
out level OK?
N
Check U201 PWR AMP
out level OK?
N
-10~0 dBm
CDMA : 25~26 dBm