ViewSonic Va703b3 Service Manual

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ViewSonic Corporation
  Confidential - Do Not Copy  VA703b-3_VA703m-3 
Factory Defaults 
Item Defaults  Item Defaults 
Contrast 70%  Volume 50% (
 for VA703m only )
Brightness 100%  Balance N/A 
Color Temperature  6500K  Treble  N/A 
Sharpness 0% Bass N/A 
OSD H. Position 50%  720x400/640x400  720x400 
OSD V. Position 50% 640x480@60Hz 
720x480@60Hz  640x480@60Hz 
OSD Time Out 
15 Sec 
In SOG and Composite, 
720x480@60Hz 
640x480@60Hz  N/A
 
OSD Background  Enabled 
In SOG and Composite,...

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ViewSonic Corporation
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TFT LCD PANEL 
 
1st  Panel Source  INN MT170EN01 V7 
Type TN, 
LVDS 
Active Size  337.92 mm (H) x 270.336mm (V) 
Pixel Arrangement RGB Vertical Stripe 
Pixel Pitch  0.264 mm 
Glass Treatment Anti Glare (Hard coating 3H) 
# of Backlights 4 CCFL edge-light  
Backlight Life  50,000 Hours (Min) 
Luminance –Condition: CT = 6500 K 
Contrast = Max, Brightness = Max 280
 cd/m2 (Typ after 30 minute warm up) 
250  cd/m2 (Min after 30...

  
ViewSonic Corporation
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3. Front Panel Function Control Description 
 
 
Adjusting the Screen Image
Use the buttons on the front control panel to display and adjust the OSD controls which display 
on the screen. The OSD controls are explained at the top of the next page and are defined in 
“Main Menu Controls” on page 10.
Main Menu
with OSD controls
Front Control Panel
shown below in detail
Scrolls through 
menu options and 
adjusts the 
displayed...

 
ViewSonic Corporation
  Confidential - Do Not Copy  VA703b-3_VA703m-3 
Do the following to ad just the display setting:
1. To display the Main Menu, press button [1].
NOTE:  All OSD menus and adjustment screens  disappear automatically after about 15 
seconds. This is adjustable through the  OSD timeout setting in the setup menu.
2. To select a control to adjust, press SorT to scroll up or down in the Main Menu.
3. After the desired control is se lected, press button [2]. A cont rol screen like the...

 
ViewSonic Corporation
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12
Main Menu Controls
Adjust the menu items shown below by using the up  S and down  T buttons.
Control Explanation
Auto Image Adjust  automatically sizes, centers, a nd fine tunes the video signal 
to eliminate waviness and distortion. Pr ess the [2] button to obtain a sharper 
image.
NOTE: Auto Image Adjust works with most common video cards. If this 
function does not work on your LCD display, then lower the video refresh rate...

 
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13
Control Explanation
User Color  Individual adjustments for red (R), green (G),  and blue (B).
1. To select color (R, G or B) press button [2].
2. To adjust selected color, press Sand T.
Important: If you select RECALL from the Main Menu when the product is 
set to a Preset Timing Mode, colors  return to the 6500K factory preset.
Information  displays the timing mode (vid eo signal input) coming from the 
graphics card in the...

 
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14
Control Explanation
Fine Tune  sharpens the focus by aligning te xt and/or graphics with pixel 
boundaries.
NOTE:  Try Auto Image Adjust first.
Sharpness  adjusts the clarity and focus of the screen image.
Setup Menu  displays the menu shown below:
Language  Select allows the user to choose th e language used in the menus and 
control screens.
Resolution Notice  displays the Resolution Notice menu shown below.
Resolution Notice...

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4. Circuit Description 
 
2.1 Switching Mode Power Supply 
2.1.1 AC Current Input Circuit
 
P801 is a connector for connecting AC Power. F801 is a fu se to protect all the circuit. AC input voltage is from 
90V to 264V. R820 and R821 joined between two inputting main  circuit to prevent man from shock. L801 is used to 
clear up low frequency wave. C801 and C806 are used  to discharge the waves that L801 produced. High 
frequency...

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ViewSonic Corporation
  Confidential - Do Not Copy  VA703b-3_VA703m-3 
 
The current flowing through CCFL is sensed and regula ted through sense resistor R509, R534. The feedback 
voltage connected to Pin5 (ISEN), then compared with a refere nce voltage (1.5V) via a current amplifier, resulting in 
PWM drive outputs to PUSH-PULL switches.
  
 
2.2.2 Protection  circuit 
 
Over Voltage Protection and over-current protection are monitored by  the voltage on VSEN(Pin 6) During 
normal operation , if a...

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3. FACTORY PRESET TIMING TABLE 
 
TIMING FH(KHz) 
FV(Hz) 
Sync 
Polarity 
Total 
(Dot/Line)
Active 
(Dot/Line)
Sync Width 
(Dot/Line)
Back Porch 
(Dot/Line) 
Pixel 
Freq.(MHz)
31.469 +  800  640  96  48 640*350@70Hz 
70.086 −  449 350  2  60  25.175 
31.469 
−  800 640  96  48 IBM 
640*400@70Hz 
70.086 + 449 400  2  35  25.175 
31.469 
−  900 720  108 54 IBM 
720*400@70Hz 
70.087 +  449 400  2  35  28.322 
24.700 
−  800 640...