Samsung SCH-A302 Service 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

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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(F

TX + 130.38 MHz)

2nd(260.76 MHz)

RX Local Freq. 1st(F

TX + 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

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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 (F

TX + 130.38 MHz)

2nd (260.76 MHz)

RX Local Frequency 1st (F

RX + 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

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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

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2-1

2. SCH-A302 Trouble Shooting

1. Logic Section

1-1. No Power

U501 pin38 Input=HIGH

Check Q507, Q509 and its

neighboring circuits

U501 pin6 & pin10

output=2.8 V?

Check U501 pin6 & pin10 and its

neighboring circuits

U501 pin39

Input=HIGH?

Check R536 and its neighboring

circuits

END

Press PWR button

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2-2

SCH-A302

Trouble Shooting

1-2. Abnormal Initial Operation

TCXO CLK

applied to U609 pina17/U404

pin7?

Check VCTCXO output.

Replace if required.

TCXO CLK

signal outputted from OSC401

pin3?

Check OSC401 and its neighboring

circuits. Replace if required.

TCXO CL

signal outputted from OSC401

pin4?

Check OSC401 and its neighvoring

circuits. Replace if required.

TCXO CL

signal outputted from OSC402

pin4?

Check OSC402 and its neighvoring

circuits. Replace if required.

LED on?

Check the LED and its neighboring

circuits. Replace if required.

Normal initial

display on LCD?

Check the LCD pins and its

neighboring circuits. Replace if

required.

Press PWR Key

END

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2-3

SCH-A302

Trouble Shooting

1-3. Abnormal Backlight Operation

‘L’ level outputted

from U501 pin1?

Check U501 pin1 and its neighboring

circuits. Replace if required.

‘L’ level outputted

from U501 pin2?

Check U501 pin1 and its neighboring

circuits. Replace if required.

Press any button on the phone

Backlight LED on

1-4. Abnormal Key Data Input

Scanning signals

outputted from U609 pins C2,

A3, E4, D3, C1?

Check keypad dom switch.

Replace if required.

Check initial status

END

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2-4

SCH-A302

Trouble Shooting

1-5. Abnormal Keytone

CLK wavefrom outputted

from U609 pin L16 & pin M17?

Check the U609 pin and its

neighboring circuits.

Replace if required.

CLK waveform outputted

from CON500 pin 5?

Resolder CON500 and its neighboring

circuits. Replace if required.

Key tone waveform

applied to C561?

Check C631. Replace if required.

Normal Keytone?

Replace the SPK assembly.

Abnormal Keytone

END

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2-5

SCH-A302

Trouble Shooting

1-6. Abnormal Alert Tone

CLK waveform outputted

from U609 pin C14.

Check the U609 pin and its

neighboring circuits. Replace if

required.

CLK waveform applied to

Q511 Base?

Check R552, Q511 and its neighboring

circuits. Replace if required.

Is the buzzer connection

correct?

Connect the buzzer correctly.

Abnormal Keytone

Check the buzzer and

replace if required.

2. Transmitter Section

Abormal transmitter section

Turn On Max PWR

Check U402 local level.

Check U204 TX RFT

out level OK?

Check U201 PWR AMP

out level OK?

-10~0 dBm

CDMA : 25~26 dBm

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2-6

SCH-A302

Trouble Shooting

3. Receiver Section : CDMA MODE

Check CDMA Rx path.

Setup CDMA call.

OK?

Normal CDMA

SVC & ROAM OK?

Check Transmitter.

Start CDMA mode

Measure CDMA FER

Normal CDMA RF?

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2-7

SCH-A302

Trouble Shooting

4. Repair Guide

4-1. TX Part Check Point

Using commands in test mode

-01, 09 (0363), 07, 34, 71 (380)

(1) 130.38 MHz (TX IF) output line

- RFT3100 (U204) PIN #14,#15 (about -30 dBm)

- IF TXIF problem Then Check TX 2ndLOCAL (260.76 MHz)

- TX 2ndLOCAL check - RFT 3100 PIN #19 (about 23 dBm)

(2) TXRF (824~849 MHz) out lines.

From RFT3100 (U204) pin #15 to CELLA_OUT

- F201 input and output is ok? - Pin #2 and #5 (about 16 dBm)

- PAM input is ok? U201 pin #2 (about 20 dBm)

- PAM voltage is ok? U201 pin #3 (3 V), 1,4 (3.7 V)

- PA output is ok? U201 pin #5 (about +10 dBm)

- Duplex input and out put is ok? Duplex input is same with PAM output. Output is You can check CN302 #2 (about 10 dBm)

4-2. RX Part Check Point

(1) RX RF (869~894 MHz) Signal input lines.

- HP Equipment setting

- RF ch 363 (RX:880.89 MHz, TX:835.89 MHz)- at CALL CTRL MENU

- sctr A pwr : -25 dBm (for more easy to check use Spectrum Analyzer)

- Rf Lvl offset : -1.4 at config screen

- Spectrum Analyzer Setting

- center Freq: 880.89 MHz (when check RXRF in 363 Ch)

- span : 5 MHz

- RF input line from Duplex to Mixer check point

- CN302 input and Duplex out (You can check Duplex out at C652) is ok?

- LNA (U360)input ,output and operating voltage is ok?

:Operating voltage-pin#1 (2.5 v) in & out (#3 66 dBm,#4 49 dBm)

- F303 input and output is ok? #2,#5 (about 50 dBm)

- RX Mixer (U361) input is ok? #1 (about 49 dBm)

(2) RF IF circuit (Received RXRF Signal + 1stlocal = RX IF (85.38 MHz fixed)

- 1stlocal is ok? U361 #4,#5 (about 13 dBm)

- Voltage is ok? U361 pin #3 3.0v

- Mixer output is ok? U361 pin #6 RXIF (85.38 Mhz-fixed) (about 50 dBm)

- F301 input and output is ok?

(3) IFR (U302) neighbor circuit

- IF input is ok? U300 pin #11,12 (about 75 dBm)

- RX 2ndlocal is ok? U300 pin #21,22 (about 25 dBm)

- 3.0 V IF (3.0IF) lines are ok? IFR operating voltage

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2-8

SCH-A302

Trouble Shooting

4-3. PLL Part Check Point

(1) VCO (Voltage Controlled Oscillator)

- Operating voltage is ok? OSC402 pin #7

- VT voltage is ok? OSC402 pin #5 (VT voltage was changed according to CH)

- Out is ok? OSC402 pin#1 output 1stlocal frequency each CH

(2) PLL(Phase Looped Lock)

- Operating voltages are ok? It use + 3.0 VR lines voltages

- TCXO_IN input is ok? U402 pin#8 It use TCXO Freq (19.68 MHz) for Reference.

4-4. Power Line Check Point

(1) U501 VBATT - #4 check

Reset - #B7 check

(2) X501 (Sleep X-tal) 32.768 MHz (pk-pk 2.7 v)

(3) TCXO(OSC401) 19.68 MHz

(4) IFR3000(U302) - #37 check TCXO-N (4.96 MHz) TCXO/N

#38 check CHIP X8-(9.84 MHz)

4-5. Reference Regulators

PM1000 U501 RESET : B7 RESET SIGNAL OUT

3.0_RX : H5 - RX CIRCUIT OPERATING VOLTAGE

3.0_TX : G5 TX CIRCUIT OPERATING VOLTAGE. (Controlled By Idle Signal)

3.0_IF : H7 RFT3100,IFR3000 AND Etc.

4-6. SAMPLING REPAIR RESULT (SCH-A302)

(1) No.1 : 24108148669 Tx Power Problem

- TX IF does not out from RFT3100 (U204) pin#1,2.

- 2ndlocal and operating voltages (3.0 IF,3.0 VR,VDC) are ok.

- Estimated factor: IFT After replace IFT It working ok.

(2) No.2 : 24108205255 - Tx Power Problem

- TX IF does not out from RFT3100 (U402)pin#6,7.

- 2

local and operating voltages (3.0_MP, 3.0_TX, 3.0_TX_IF, 3.0_TXRF, 3.0_TX_LO) are ok.

- PA ON signal does not out from MSM.

- MSM also failed to J-TAG Tester.

- Estimated factor: MSM defect

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2-9

SCH-A302

Trouble Shooting

(3) No.3 : 24108167813 - Tx Power Problem

- All TX path is good from RFT 3100 to Mixer input port.

- Mixer output is lower than normal status.

- 1

local and operating voltages are ok.

- TX AGC ADJ voltage is too low.

- Estimated factor: Chip capacitor (C203) which connect to TX AGC ADJ

voltage line C203 Replace ok.

(4) No.4 : Tx Power Problem

- All TX path and voltages are ok from Duplex input to RFT3100 input

- CELLA_OUT (-pin#17) is ok, But U201 RF_IN (-pin#2)is not good.

- Estimated factor : F201 Replace ok.

(5) No.5 : 24108146584 When touch MSM, RX RSSI value has lost.

- All RX path is good from Duplex to Mixer input port .

- 1

local & TCXO did not oscillate.

- TCXO upper case pushed then case and inside components were short when B'D is twisted.

Estimated factor : TCXO After replace TCXO It working ok.

(6) No.6 : 24108221088 - Problem with display (When power on, display was abnormal working)

- LCD and neighbor patterns are ok.

- Estimated Factor: Broken data which is in E2PROM. Data Rebuilding OK

(7) No.7 : 24108134768 - RX problem (No SVC)

- Handset doe not acquire SVC then searching CH repeat very quickly.

- All RX value is good at Rx Part Check Point.

- Ec/Io value (in debug screen) is bad.

- Estimated factor : MSM does not decode receiving signal.

(8) No.8 : No Power on (Can't not power on)

- X501 Sleep X-tal (32.768 MHz) is O.K

- V_DC 3.0V is O.K

- CHIP X8 No output IFR #38

- TCXO_N No output IFR #37

- TCXO Not oscillator Pin # 3

- TCXO crack : TCXO replace O.K

(9) No.9 : 24108233382 - ESN INVALID

- ESN No was broken : 0000000

- ESN data at E2PROM was broken caused ESD or Electric shock.

- E2PROM replace and rewriting ESN number.

3. S CH-A302 Tune-up Rrocedure & Test Procedure list

1. List of Equipment

•

DC Power Supply

• Test Jig : HHP I/F TESTJIG GH80-10502C

• Test Cable : GH3900052A

• RF Cable : GH3900075A

• CDMA Mobile Station Test Set HP8924C, HP83236A, CMD-80, etc

•

Spectrum Analyzer(include CDMATest Mode) HP8596E

2. Configuration of Test

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3-1

RF cable

DUT

Data cable

Test Jig

T o A-Out

T o A-In

Directional

Coupler

DC Power Supply

(+3.93 V)

IN/OUT

Audio

OUT

Audio

HP8924C

RF IN

Spectrum Analyzer

• CAUTION : The test jig and data cable has a voltage drop of 0.15 V at FM Max power output,

you’d better set the DC power supply is 3.8 V for normal test condition. (Nominal voltage of battery is 3.8 V at cellular phone)

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3-2

SCH-A302 Tune-up Rrocedure & Test Procedure list

3-2. Test Cable Connections

1 MHC 172 2 RF CABLE (1.4 dB Loss for CDMA800 and AMPS, 2.1 dB Loss for PCS) 3 BNC CONECTOR (RF) 4 PLUG CONNECT TO SCH-A302 5 DATA CABLE 6 Dsub 25PIN CONNECTOR (DATA)

3. Test Cable Description for SCH-A302

3-1. Test Cable

Change to T

est Mode

A. To Change the phone’s state from Normal Mode to Test Mode, You should enter the following keys.

: Press [ 7 5 9 # 8 1 3 5 8 0 "(A+Y)"]

B. The Command “2 1” is mode and channel change.

“20363”

Channel number Mode : CDMA

and Push the [OK] Key to save. C. The command “0 1” is Suspend. D. To finish the Test Mode, You should enter the command “0 2”.

Channel Selection and Tx Power Output Level Control

1. CDMA

A. Enter to Test Mode [ 7 5 9 # 8 1 3 5 8 0 "(A+Y)"] B. The command “2 1” is mode and channel change.

“20363”

Channel number Mode : CDMA

Push the [OK] Key to save.

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