【 Weak current College 】 homemade projector utility maintenance technical information (3)---Power By 【 China power house network 】

6, projection distance
Projector from the projection screen of effective distance.
7, screen aspect ratio
An image or screen width and height of the projection ratio, aspect ratio 4: 3, 16: 9 is also compatible.
8, color
Is the projection screen to reflect the richness of color. Higher numbers indicate projector can provide richer colors, almost all of the projector color number can reach 16.7 millions of colors. This number is a combination of ASP from RGB color. That is, 256 × 256 × 256 = 16777216.
9, effective scanning frequency
Divided into horizontal scan frequency (row frequency) and vertical scanning frequencies (field frequency). Horizontal scan frequency: video projector horizontal scan frequency is fixed, as 15.625KHZ (PAL) or 15.725KHZ (NTSC) projector can automatically track the input row frequency, by phase-locked circuit and input signal row frequency of full synchronization. Horizontal scan frequency is important to distinguish between projector quality indicators: the frequency range in 15KHZ-60KHZ projector is commonly referred to as data projectors; more than the maximum frequency is usually called graphics 60KHZ projectors. Vertical scan frequency: vertical scanning frequency is also called refresh frequency, it indicates that the image is the number of times per second refresh. Vertical scanning frequency is generally not less than 50HZ, otherwise the image will flicker.
10, input terminals
Projector to the input signal interface. RCA connector: used in most stereo equipment and recorders, audio and video input jacks. BNC connector: typically used for workstation and coaxial cable connector. BNC cable 5 connector to receive the red, green, blue, horizontal and vertical synchronization signal synchronization.
11, output terminals
Projector to output video signal interface. DIN connector: one for the 4-core round S-VHS.
12, nominal values for brightness uniformity
I.e. Unifoumity, refers to the lightest projector image and darkest parts of the differences in value, generally speaking, the lightest projector will be part of the center of the screen, the darkest places on the edge of the screen. So when the higher the degree of uniformity to the center of the screen edge, the higher the consistency, uniformity and less bright than a picture of the situation is more serious.
13, video signal mode
The world's leading standard for PAL and NTSC. NTSC (national television system Committee, United States), North America, Japan, South America and some countries of the television standard. NTSC has 525 lines of resolution with 60 Hz refresh rate. NTSC is the video or TV signal. PAL (phase-by-row), Western Europe, Asia, Australia, Africa and South America and some countries of the television standard. PAL 625 lines of resolution and refresh rate of 50 Hz.
14. light bulb
Early projector common metal halogen bulb, as the 1990s Sharpe company of projectors, video machines, such as 315, 370, 3300, 7000, T2Z, PN500, etc. The advantages of metal halogen lamp is cheap, the disadvantage is that the short half-life, general use 1000 hour brightness decreases to about half of the original, and due to the high fever, on projector thermal system requirements, it is not advisable to do long time (4 hours) projection used. Now the most recently used for UHE, cold light source lamp UHP, mainly for multimedia projector. UHE lamp advantage is affordable, with 4000 hours ago brightness almost no decay. Due to the low power consumption, customarily referred to as cold light source. UHE lamp is currently widely used in the mid-range projector ideal light source, UHP bulb advantage is long life, can be generally more than 4000 hours of normal use, and brightness falloff is very small. UHP is an ideal cold light source, but as a result of higher prices, generally apply to high-end projectors, special note: use a different brand of projector bulbs generally cannot be used interchangeably,so buy projector must be understood, so as to avoid the lamp after use and can not buy the right light bulb, projector scrap. Second, the maintenance of the projector
After using the projector for a long time, like screen turned yellow, gray, brightness, blur, and most projectors are used for a variety of entertainment, the user does not pay attention to maintenance, in the course of time the projector will appear in a wide variety of failures. According to the survey most projectors are used and fault caused by improper maintenance. As we all know, the projector is set, light, electricity, machinery for the integration of high-precision equipment, due to the small size of the projector lamp, built-in high temperature generally fan cooling, this inevitably will dust into the air in the tank, if long-term not clean, will result in the build-in thermal performance, insulation capacity, the drop shadow effect and decrease with life, the main problems: the LCD Board damage, the main devices of premature ageing, Polaroid roast bad, etc. Therefore, regular maintenance and upkeep of the projector is to reduce the damage to the equipment's primary task. Instead of normal control their optical path cleaning every maintenance personnel must be available, below the import of domestic projectors and professional multimedia projector Optics Engine cleaning methods for details.
1, domestic chip projector Optics Engine cleaning
Because single-chip LCD optical engine simpler, easier to clean. As Figure 5 and 6:

Cleaning except reflective Bowl, coated reflector, LCD, available in the dishwashing detergent to clean water, distilled water cleaning conditions available, and the results are particularly good, do not use alcohol and organic solvent, such as banana water for cleaning. In addition,As a result of domestic reflective Bowl, coated reflector of poor quality, can only be used tobrush gently brush xiaomao surface dust, if dirt too much and cannot be removed, you can only replace a new one. Which Bowl and imported reflective coated reflector is available for cotton wool and water cleaning, wipe the lens cleaning paper mirror available for scrubbing.