Samsung STH-A225 User manual

SERVICE
TDMA MOBILE
TELEPHONE
STH-A225
2
C
ABC
4
GHI
13
DEF
5
JKL
6
MNO
7
PQRS
8
TUV
0
9
WXYZ
Manual
TDMA MOBILE TELEPHONE CONTENTS
1. Trouble Shooting
2. Electrical Parts List
3. Exploded Views and Parts List
4. Block Diagrams
5. PCB Diagrams
6. Circuit Description &
Circuit Diagrams

©Samsung Electronics Co.,Ltd. December. 2001
Pinted in Korea.
Code No.: GH68-01930A
BASIC.
ELECTRONICS

SAMSUNG Proprietary-Contents may change without notice
1-1
1. STH-A225 Trouble Shooting
1. Baseband Section
1-1. Program No Running
N
Need to check
Q204, U311
N
Replace dome S/W
N
Need to check
Q204, U311
N
Need to replace
Memory(U206)
N
Need to check neighbor part
Need to check OSC302,
U202 & neighbor part
Press END Key
Y
Y
Y
Y
Y
Y
ON_SW=H
VBAT>3.2V
VCTCXO_IN=14.4 MHz
32K_XIN=32.768 kHZ
Memory (U206)
control signal OK?
VCC=3.0V
V_VCTCXO=3.0V
RST=3.0V
IVCC=2.2V
BOOT=H
Program Running
VCC, ADD(0:21), DATA(0:15),
FLASH_CS, SRAM_CS, UBE,
MEMOEB, MEMWEB

SAMSUNG Proprietary-Contents may change without notice
1-2
STH-A225 Trouble Shooting
1-2. Abnormal LCD display ,EL Baob Light, Vibrator & Speaker Operation
Y
LCD module
Good
N
Replace LCD module
Y
Speaker Output OK?
N
Need to check
CN101 & neighbor part
N
Need to check
CN101
START
Y
Y
LCD Control
Signal OK?
Y
Y
EL_EN=H
N
Y
EL Back light
OK?
VCC, ADD(2), DATA(0:7),
DISPLAY_CS, RST
LCD Display Running
Send Command EL
enable(Test mode:176)
N
Need to check
CN101
Y
Y
VIBRATOR=H
N
Replace LCD module
Y
Vibrator Run
OK?
LCD Display Running
EL Back lingt Running
Send Command Vibrator
enable(Test mode:180)
N
Need to check CN101
& neighbor part
Y
SPK+,SPK-
Signal OK?
LCD EL Vibrator OK Send Command
Main Audio Receiver Path ON
(Test mode:031, 131, 134, 185)
Need to check U106 out pin5
2.8 V al control pin3 ‘H’

SAMSUNG Proprietary-Contents may change without notice
1-3
STH-A225 Trouble Shooting
1-3. Abnormal Key, Mic, LED’S operation
N
Need to check CN102-1
& neighbor part
N
Need to check CN102-1,
Q102 & neighbor part
Press Keys
Y
Y
Key Dispaly
OK?
Y
Key Display Good
Send Command Main Audio Path ON
(Test mode:031, 131, 136, 187)
Talking Voice at MIC+
N
Need to check
CN102-1 & neighbor part
Y
Y
Y
LED Operation
OK?
Key Display Good
Mic Path Good
Send Command ALT_LED_ON
Send Command SVC_LED_ON
Send Command LED_ON
(Test mode:178)
Audio signal output
at Speaker?
GOOD

SAMSUNG Proprietary-Contents may change without notice
1-4
STH-A225 Trouble Shooting
1-4. Abnormal Buzzer Operation
START
Y
N
Need to check
U104 & AU101
Y
Y
Ringer Signal
OK?
Send Command Ringer Path ON
(Test mode:183)
N
Replace AU101
Y
Buzzer Sound Output
OK?
Buzzer Operation
Good

SAMSUNG Proprietary-Contents may change without notice
1-5
STH-A225 Trouble Shooting
1-5. Abnormal external Ear_Mic Jack operation
START
Y
N
Need to check Q103,
U102 & neighbor parts
Y
Y
HS_SENSE=H
Hock Up Ear_Mic Phone in the Jack(U313)
Send Command MIC_BIAS_EN enable Send
Command AMP_EN enable
Audio set Path=HS
(Test mode:187, 185, 032)
N
Need to check Q103,
U102 & neighbor parts
Y
Y
SEND_END=H
Press Button on the Ear-Jack
Ear_Mic phone
Operation Good

SAMSUNG Proprietary-Contents may change without notice
1-6
STH-A225 Trouble Shooting
2. RF Section
2-1. Call processing and Online Test
N
DONE
START
Y
Y
Normal SVC?
Check RX path
N
Y
Set up Call OK?
Check TX path
N
Y
Measure SINAD/BER
Good?
Check RX path
N
Y
Measure
Tx Power Good?
Check TX path

SAMSUNG Proprietary-Contents may change without notice
1-7
STH-A225 Trouble Shooting
2-2. Receiver Section (Offline test)
1
Y
Y
N
Need to check
U209, U208, U207
Y
N
Need to check
F306
U301_8=-54dBm
N
Need to check
F304 & neighbor parts
Y
RF_BAND=L, RX_BAT=H
PLL_ON=H, PON_LC=H
VCTCXO_PC=H, IF_ON=H
PON_VRF3=H
set up 8920B basestation for RX test
Set Base station RX Lev=-50 dBm
Send Command RX path ON
Send Command channel selecton
(Test mode:031)
START
N
Y
V_LNA_CELL=H
U208_1=H
U207_1=H
Need to check
U301 & neighbor parts
F304 input=-34dBm
2
U304_45=-35dBm

SAMSUNG Proprietary-Contents may change without notice
1-8
STH-A225 Trouble Shooting
2
N
N
AMPSTDMA
N
Replace U304
Replace
F302
Need to check OSC301,
neighbor parts & U304_1,2,3
Need to check
U207 & neighbor parts
N
Y
Y
Y
Y
YRF loal check
U304_48 Lev=-5dBm
Freq=adjusted freq?
1
U304_41 Lev=-19dBm
Freq=130.05MHz
U304_34 Lev=-26dBm
Freq=130.05MHz
NNeed to check
U304, L303, C308, L301, C307
U304_37 Lev=4dBm
Freq=450kHz
Y
NReplace F301 or
Need to check R302, R304, C301
U304_25 Lev=-2dBm
Freq=450kHz
MODE
U304_40, 42=3.0V
43