ViewSonic VA902B Service Manual - Page 26

8 After repair, to ensure the quality you should do the following test and adjustment Item Test OSD function Contrast Check Content 1.Signal is set as 1280x1024@60Hz 2. LCM button are from left to right, checking whether each single function key and compound function key can be worked. 1. Set input mode to 1280x1024@60Hz 2. Set Pattern to 32 gray shades 3. Set contrast to the max. The brightest 5~6 shades brightness cannot be distinguished. Equipment Chroma Signal Generator Chroma Signal Generator Color Temperature 1. Do "Auto color" at 1280 x 1024@60Hz, 32gray shades 2. Measure color temperature, check it complies with the following temperature: 5400K x=0.335 +/- 0.02, y=0.350 +/- 0.02 6500K x=0.313 +/- 0.02, y=0.329 +/- 0.02 9300K x=0.283 +/- 0.02, y=0.298 +/- 0.02 Chroma Signal Generator and color analyzer Modes switching check 1. Use Chroma Pattern Generator to make sequence. VESA (640x480 800x600 1024x768 1280x1024), MAC 832x624 DOS (640x350 720x400), the detail supported modes and power saving signal. 2. Confirm the above timing modes must be full screen and the picture must be normal. 3. LED is Orange at power saving mode. Chroma Signal Generator Y measurement at default setting Panel Flicker check 1. Set brightness to default value 100 and contrast to default value 70 at 6500K 2. At full white patter, Measure Y, which should be >=200cd/m² Chroma Signal Generator and Color Analyzer 1. Mode: 1280x1024@60Hz 2. Set Brightness& contrast to default value 3. Do "Auto Image Adjust" 4. Shut down PC to check whether there's glitter on the center of the picture. Equipment:: Chroma Signal Generator & PC Power saving 1. Mode: 1280x1024@60Hz 2. Pattern: full white 3. Brightness: Max. 4. Contrast: Default 5. Check power consumption at each modes State Power Consumption Normal ＜40Ｗ Stand By ＜1Ｗ Power Key Off ＜1Ｗ LED color Green Orange No Chroma signal generator and Power meter AC input: 230V/50Hz ViewSonic Corporation Confidential - Do Not Copy VA902/b 23