ViewSonic Vx2255wmb-2 Service Manual

							
 
 
 
 
 
6.5 Backlight can’t be turned on 
 58 
ViewSonic Corporation 
Confidential - Do Not Copy    VX2255wmb-2 
  VX2255wmh-2  
						

							
6.6 Black Screen and backlight turn on 
 
Black Screen
Check VCC 
5V Power Fail 
Check VCC 3.3V a n d  
VCC 1.8V  Check  
FB103
Check Reset 
Waveform Check C151 
Check Crystal pin(96,97)waveform Check 
Check CCFL 
Enable Check 
pin10 of 
Invert fail 
U104 fail 
Check R147,R111,R112, 
and Q106 
NG
OK
OK
OK
OK
NG 
OK OK
NG
NG 
NG
Check Crystal Waveform 
Check 
FB102
NG
 59 
ViewSonic Corporation 
Confidential - Do Not Copy    VX2255wmb-2 
  VX2255wmh-2  
						

							
6.7  White Screen 
 
LVDS cable 
reinser
t 
NG 
Change LVDS 
cable 
NG 
Check VLCD   
Is 5V 
NG 
Check panel Enable 
of Panel Enable 
OK 
Check 
Q101,Q103 and 
END 
OK
OK
OK Check VLCD
sin
gals
Workmanship 
LVDS cable NG 
OK
Panel Fail 
Check CN104 
White Screen 
 60 
ViewSonic Corporation 
Confidential - Do Not Copy    VX2255wmb-2 
  VX2255wmh-2  
						

							
6.8 Bad  Screen 
 
 
 
 
 
 
 
  Bad Screen   
LV D S   
Cable 
    
Reinsert   
NG   
Change LVDS   
Cable  
NG   
Check  Stalcry pin   
127 and pin128   
OK   
CheckU105and 
SDO/SCZ/SCKSDI /RSTN   
OK
 
NG  
Workmanship  
Check X1,C150 and 
C152 
  
SDO/SCZ/SCK/SDI 
 61 
ViewSonic Corporation 
Confidential - Do Not Copy    VX2255wmb-2 
  VX2255wmh-2  
						

							
 62 
ViewSonic Corporation 
Confidential - Do Not Copy    VX2255wmb-2 
  VX2255wmh-2 
7. Block Diagram 
EMI Filter Circuit
5V Switch 
to Panel
 
Power 
Switch 
transformer
Regulator (5Vto 1.8V
)
 Inverter Circuit 
OZ9938G 
Rectifier/ filter 5V Output 
Photocoupler
Protection feedback
EEPROM 
AT24C04N
(VGA)
Key & LED
Sampling Voltage feedback
 
EEPROM 
24C04 
Audio Input AC Input VGA Input Key Input 
Speaker
 
 
Panel 
Back lamp 
Regulator (5V to 3.3V
)
Rectifier& 
Filter Circuit
Rectifier/ filter 
16V Output Sampling 
Voltage
 
feedbac
k
VGA Input 
Circuit
 
 
 
SCALER 
& MCU 
( TSUMU58J)
Audio Amplifier (TDA8496L) MCU 
Volume Control 
16V Input 
ON/OFF  
& Brightness
ON/OFF 
PWM Control 
NCP1337 
EEPROM 
AT24C04N
(DVI) 
DVI Input(HDCP)   
DVI Input 
Circuit(Option)
Flash memory
F/W Code
MOSFET 
Switch 
  
						

							
 63
 
ViewSonic Corporation 
Confidential - Do Not Copy    
VX2255wmb-2 
  VX2255wmh-2 8. Schematic Diagrams  
Model
TitleDate Rev:ViewSonic Corporation
DC to DC
From Power
& Inverter
From keypad
LED_A
LED_G
Backlight_ON/OFF
Backlight_ON/OFF Adjust_Brightness
Adjust_Brightness LED_A
LED_G
VLCD
VCC5V
VCC1.8
VCC3.3
VCC3.3VCC3.3
VCC3.3
VCC5V
VCC5V
C107 0.1/16V
R104 20K
R107 1K
C109 0.1/16V
U101
AP1084K33LA
3
1
2
VIN
ADJVOUT
R112 100
C110
1u/16V
R101 4K7
R110 4K7
R108 4K7
C105 0.1/16V
R109 220
R106 4K7
C103 0.1/16V
Q106
PMBT3904
1
32
Q104
PMBT3904
1
32
U102
LD1117AL-1.8V
3
1
2
VIN
ADJVOUT
R105 220CN102
2x4P 2.0mm
12345678
1
3 2
Q102
PMBT3906
CN101
8P 2.0mm
123456781
2
3
4
5
6
7
8
Q101
AP2305GN1
3
2
C111
NC/1u/16V
1
3 2
Q105
PMBT3906
D101
SKS20-04AT
R103 51
R102 1K
C106 0.1/16V
C101 0.1/16V
C104 0.1/16V
Q103
2N70021
32
+C108 100u/16V
R111 4K7
+C102 100u/16V
LED_G_C 4
LED_A_C 4
Panel_Enable
VLCD 4
CCFL_Enable 4
VCC1.8 4
VCC3.3
3,4
Volume
4Mute
4
Brightness_PWM 4
RIGHT 4AUTO 4MENU 4LEFT 4POWER 4 
						

							
 64
 
ViewSonic Corporation 
Confidential - Do Not Copy    
VX2255wmb-2 
  VX2255wmh-2 
Model
TitleDate Rev:ViewSonic Corporation
Input
DETECT R
B G
G
B
R
DETECT
DAT0-
DCLK- DAT1+
DCLK+ DAT2-
DAT0+ DAT2+
DAT1-
SDA_DVI SCL_DVI DAT0-
DAT1-
DCLK- DAT1+ DAT0+
DAT2+
DDCA_SDA DDCA_SCL DDCA_SCL
DCLK+
DAT2- DDCA_SDA
SCL_DVI
SDA_DVI
PC5V_VGA
VCC3.3PC5V_VGA
VCC3.3
VCC3.3
DVI5V
DVI5VVCC3.3
VCC3.3
C114 0.047u/16V
CN201
DVI-D_CON
123456789101112131415161718192021222324
RX2-
RX2+ GND
RX4-
RX4+
SCL
SDA VS
RX1-
RX1+ GND
RX3-
RX3+ 5V
GND HP
RX0-
RX0+
GND
RX5-
RX5+
GND
RXC+
RXC-
R202 100
D103
BAV99
1
3
2
C201 0.1/16V
R115 100R126 100
R215 10 1%
D201
BAV991
3
2
R217 10 1%
C122 33p/50V
ZD101 5V6
CN103
DZ11AA1-H5W6-4F
162738495
1112131415
10
1617
D104
BAV99
1
3
2
R205 4K7
R201 10 1%
ZD102 5V6
R120 470
R128 75 1%
R207 4K7
R114 100
D204
BAV991
3
2
C113 0.047u/16V
ZD202 5V6
R124 100R117 100
R214 10 1%
D105
BAV99
1
3
2
C202 0.1/16V
C115 0.047u/16V
R216 10 1%
D207
BAV991
3
2
R123 1K
U103
AT24C02BN
1234
5678
A0
A1
A2
GND SDA SCLWP
VCC
C125 0.1/16V
ZD103 5V6
R133 4K7
R116 100
C112 0.047u/16V
R203 100
C120 NC/33p/50V
D205
BAV991
3
2
R213 10 1%
R131 2K2
C119 NC/33p/50V
R118 100
C117 0.047u/16V
R211 10 1%
R122 10K
ZD203 5V6
U201
AT24C02BN
1234
5678
A0
A1
A2
GND SDA SCLWP
VCC
ZD104 5V6
D208
BAV991
3
2
R129 75 1%
1
3 2
Q201
PMBT3906
FB101
120Ω
R134 4K7
C116 0.047u/16V
C124 NC/0.1/16V
D206
BAV991
3
2
R119 100R125 100
ZD201 5V6
R212 10 1%
R218 4K7
C121 NC/33p/50V
D106
BAV70
3
21
R132 2K2
C123 220p/50V
R204 4K7
D102
BAV99
1
3
2
R206 4K7
ZD105 5V6
D203
BAV991
3
2
R127 100
R130 75 1%
C118 0.047u/16V
D202
BAV70
3
21
D209
BAV991
3
2
GNDR 4GIN 4GNDG 4RIN 4SOG 4
VSYNC 4
GNDB 4BIN 4
HSYNC 4DET_VGA 4
VCC3.3
2,4
DET_DVI 4HP_CTRL 4
WP_DVI 4
B- 4B+ 4G- 4CLK- 4R+ 4CLK+ 4R- 4G+ 4
WP_VGA 4
DDCA_SCL 4DDCA_SDA 4
SCL_DVI 4SDA_DVI 4 
						

							
 65
 
ViewSonic Corporation 
Confidential - Do Not Copy    
VX2255wmb-2 
  VX2255wmh-2 
Model
TitleDate Rev:ViewSonic Corporation
SCALER
4
5
6
7
8
F_WP
I2C_MDA HDCP_WP
EEP_W P
I2C_MCL SDO
SCK
7
SDI 4
SCZ 6 5
I2C_MCLEEP_WP
I2C_MDA F_WP
8
HDCP_WP
76
845
VCC3.3
VDDP_33
VDDC_18
VCC1.8
AVDD_18
AVDD_33
VCC3.3
AVDD_33
VCC5V
VDDP_33
AVDD_18
VDDC_18
VDDP_33
AVDD_33
VLCD
VCC3.3
VCC3.3
R140 4K7
R146 4K7
C139 0.1/16V
C161 0.1/16V
C158 0.1/16V
R154
1K
C145 0.1/16V
C159
0.1/16V
R141 10K
R147 4K7
C130 0.1/16V
C141 0.1/16V
U105
SST25VF010A
12
34
56
78
CS#SO
WP#
GND SI SCK
HOLD# VCC
FB102
60Ω
C143 0.1/16V
R168 10K
C146 0.1/16VC135 0.1/16V
R136 4K7
R142 10K
C134 0.1/16V
R167 NC/0
R158 100
R135 4K7
CN104
FFC-CON1 2
3 4 6 8 10 12
14 16 18 20 22
24 26 28 30
7 9 11 13 15 17
19 21 23 25 27
29
5
C127 0.1/16V
R210 4K7
C152 22p/50V
R169 NC/0
R155 1K
R148 4K7
R137 4K7
R143 4K7
X1
14.31818MHz
FB103
60Ω
R209 4K7
R159 1KR1561K
C153 0.1/16V
C132 0.1/16V
C148
1u/16V
C144 0.1/16V
TSUMU58JU104
2825262327242232337313041434244
5180
128127
818283848586919293949596979899100797877
111
9101213
8
15161819
172952
104
87
37
103
112
343556
118
14
107
3673119120121123124
117116115
3839
108
34
5374
4059
7288101
7675
102
109
126
114
111110
20
9089
1222
113
5655
57
61647067
21
106105
474648504945
68696362
60656671
125
5458
RIN0P
GIN0P
SOGIN0
BIN0P RIN0M
GIN0M
BIN0M
HSYNC0
VSYNC0
REXT
REFP
REFM
SDO
SCK CSZ
SDI GPIO_P24/PWM2
LVACKM
XIN
XOUT
LVA2P
LVA2M LVA1P
LVA1M LVA0P
LVA0M
LVB3P
LVB3M
LVBCKP
LVBCKM LVB2P
LVB2M LVB1P
LVB1M LVB0P
LVB0M
LVACKP LVA3M
LVA3PGND
GNDRX2P
RX2N
RX1P
RX1N
AVDD_33
RX0P
RX0N
RXCKP
RXCKN
GND
GND
GND
VDDC
VDDP
MODE
VCTRL VDDP
DDCA_SDA/RS232_TX
DDCA_SCL/RS232_RX
DDCD_SDA
DDCD_SCL
NC AVDD_33
VDDP
GPIO_P22/PWM1 GPIO_P04
GPIO_P00/SAR0
GPIO_P01/SAR1
GPIO_P02/SAR2
GPIO_P06
GPIO_P07
NC NC NC
I2C_MDAI2C_MCL
RST GPIO_P15
GPIO_P16
VDDC
VDDC
VDDP
VDDP
GND
GND
GND
LVA4M LVA4P
BYPASS GPIO_P25
VDDC
VDDP
NC
NC AVDD_33
LVB4M LVB4P
GPIO_P03/SAR3
GPIO_P14/PWM0
GND
NC
NC NC
NC
NC
NC
NC AVDD_18
GND GND
GPIO45
GPIO46 GPIO44
GPIO42
GPIO43
GPIO47
GND
GND
GND
GND
VDDP
VDDP
VDDP
VDDP
GPIO_P13/PWM2
VDDP VDDP
R164 4K7
R149 4K7
C131 0.1/16V
R208 4K7
R162 100
R138 4K7
R144 4K7
+C151
10u/25V
+C126 22u/25V
U202
AT24C04N
1234
5678 A0
A1
A2
GND
SDA SCL WP
VCC
R150 4K7
R160
1K
C150 22p/50V
U107
AT24C04N
1234
5678
A0
A1
A2
GND
SDA SCL WP
VCC
R163
390 1%
R139 4K7
R157 100
C149 0.1/16V
R151 4K7
C128 0.1/16V
C133 0.1/16V
C136 0.1/16V
C140 0.1/16V
R161 100
C154
0.1/16V
C160 0.1/16V
R165 10K
C157 0.1/16V
C137 0.1/16V
R153
1K
+C142 22u/25V
R166 NC/10K
R152 4K7
C138 0.1/16V
C147 0.1/16V
C129 0.1/16V
DDCA_SDA
3
VCC5V
SDA_DVI
3
B+
3G+
3R-
3CLK+
3G-
3CLK-
3R+
3B-
3
HSYNC
3VSYNC
3SOG
3GNDG
3GNDR
3RIN
3GIN
3GNDB
3BIN
3
DDCA_SCL
3
AUTO 2LED_A_C 2LED_G_C 2CCFL_Enable 2DET_VGA 3Brightness_PWM 2WP_DVI 3Volume 2WP_VG A 3Mute 2Panel_Enable 2HP_CTRL 3MENU 2DET_DVI 3LEFT 2POWER 2RIGHT 2
SCL_DVI
3 
						

							
 66
 
ViewSonic Corporation 
Confidential - Do Not Copy    
VX2255wmb-2 
  VX2255wmh-2 
Model
TitleDate Rev:ViewSonic Corporation
Power
AC 264V  RMS
L
AC 264V  RMS AC 264V  RMS
DC 380V Max.
N
DC 700V Max.
DC
700V
Max.
TO SCALER BD CN101
AC 264V  RMS
VCC5V 3+16V3,4
ON/OFF 3BRIGHTNESS 3VOL4MUTE 4
F802
4A/125V
C823
2200p/400V
+
C817
470u/25V
R816
100R 1W
R824
3K 1%
+
C807
47u/25V
R822
4K7 1%
R818
NC / 200
D802
MUR1100ERL
C825
0.1/50V
R829 15K
+
C818
1000u/10V
IC802
NCP1337
1234
5678
BOFB
CS
GND
DRV
Vcc
NC
HV
ZD802
P6KE150A
+C815
1000u/25V
R811
510K
R814
NC/ 1K
ZD804
NC / 14V
C813
1000p/500VC814
1000p/500V
R832
750 1


R823
47K 1%
-+
D801
UL4-06
1
2
4
3
C806
4700p/400V
R807
680 1


ZD803
12V
R827 10R
C809
47p/1KV
R819
1K
R810
510K
R830
10K
R815
12K 1%
C803
0.47/275V
CN802
60mm 8P
1 2 3 4 5 6 7 8
1
3 2 Q803
NC/ PMBT3906
C811 0.1/50V
IC801
LTV817M
3
1
4
2
R817200R
R812
10K
C812
220p/50V
C805
2200p/400V NC
C826
12p/1KV
+C820
47u/25V
Q801
2PC1815GR1
3
2
R813 1K
R802
1M
D806
1N4148
C821
0.1/100V
R804
68R 1/2W12
+
C804
150u/420V
C822
0.1/50V
C808
100p/1KV
C
R
AIC803
TLV431ALP
L801
20mH
4
1
3
2
R821 1K
R805
0R18 2W
D803
A02-LF
F801
2.5A/250V
+
C827
47u/25V
R801
1M
R831
680 1


L803 5uH
D805
SRF1045CM
1
2
3
D804
UFF80-015CT
1
2
3
+
C819
1000u/10V
R820
1K
R806
10R
T801
EER28
12354
108976
R828 10R
C810
0.1/50V
RT801 NTC 5R
C802
2200p/250V
C801
2200p/250V
Q804
AP2761I1
23
R803
18K
L802 5uH
P801
AC_SKT1
2
3
R809
510KR808
510K
VCC5V 3 
						

							
 67
 
ViewSonic Corporation 
Confidential - Do Not Copy    
VX2255wmb-2 
  VX2255wmh-2 
Model
TitleDate Rev:ViewSonic Corporation
Audio
MIC JACK
For VSC 22W, Jumper J701/J702 are NC 
For Acer 22W, 20 and VSC 20 , CN702/CN703 are NC LEFT_SPEAKER+
Line_R
RIGHT_SPEAKER+
Line_L
MIC-
MIC+
+16V 2,3
MUTE
2VOL
2
+16V
+16V
+16V
Q702
PMBT3904
1
32
U701
TDA8496L
8
1115
5
4
3
2
6
1
7
910
14
13
12
S_GND
GND
GND
INL
VAROUT_L
VOLUME VAROUT_R
NC
INR
SVR
STBY MUTE OUTR
VSOUTL
R702
10K
R714
30K
CN703
5P 2.0mm/NC
5
4
3
2
1
C710 4700p/50V
C709 0.1/50V
R705
30K
R703
10K
R706
1K
R710 2K
+C702
470u/25V
R704
47K
R701
10K
C711 4700p/50V
+C707
470u/16V
R713 100
CN701
4P 2.0mm 90°1
2
3
4
+C705
470u/16V
+C712
470u/25V/NC
C703
0.1/50V
R712 5K6
C704 0.47/16V
R711
5K6
R709 2K
Q703
PMBT3904
1
32
+C701 10u/25V
P701
4321
R707 1K
Q701
PMBT3904
1
32
CN702
2P 2.0mm 90°/NC
1 2
+C708 220u/16V
C706 0.47/16V
R708 4K7