Service manual

C193
100U
1
2
V33
RSTn
SW1
SW_MOM_4P
1
2
4
3
U19
CAT809RTB
RESET
R
VCC
I
GND
G
R140
5.6K
V33
R141
2.2K_NC
RESET
RESET IC
MSP4440K,PWM2030
To RESET TUNER, HDMI
To RESET PW106
U20
74LVC1G126
1
2
4
3
5
C194 .1
V33
RESETn P{2,4,12,14,15}
v. PANELVCC ON
In the period of POWER ON, the signal of control PANELVCC output a Hi level signal from PW328
I/O port PNLPWR, PANELVCC will supply power to Panel via LVDS output Header J4.
For 37" LG AUO Panel
For 32" Samsung Auo Panel
L119 PBY20-221
L120 PBY20-221
Q21
AP4435M
S1
1
S1
2
S1
3
G1
4
D1
8
D1
7
D1
6
D1
5
C503
.1
C502
100U
12
R334
10K
Q22
3904
CE
B
R335
10K
R331 10K
PNLPWRP{9}
VCC
PANELVCC
V12
PANELVCC ON/OFF
vi. INVERTER ON
When POWER ON, the signal of control Backlight-ON will output from I/O port BKLTPWR of U18
PW328 via Q20, Q19 to 13
th
pin of J11 and sends to Switching Power supply. Then Switching
Power Supply forwards the signal to the Inverter of Panel and turn it on.
INVERTERON/OFF
C492
.1
R318 0_NC
R322
510
R319
0
R325 10K
C493
10U_NC
1
2
R326
10K
J11
1
2
3
4
5
6
7
8
9
10
11
12
13
BKLTPWRP{9}
VCC
Vsub
V12IN
Q19
2N7002
D
G
S
For 32" Power
For 37" Power
Q20
3904
C
E
B
R324
10K
Vsub
Backlight ON=4.5V
vii. BACKLIGHT ADJUST
The signal of Backlight Adjust which output from PWM I/O port of U18 PW328 sending a PWM
signal to U42 C491 converged into a DC signal then forward to Inverter of Panel via 12
th
pin of J11
to adjust the brightness of Backlight.
ViewSonic Corporation Confidential - Do Not Copy N4261w-1M
9