Written Report ICT

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Bicol University

College of Arts and Letters

Academic Year 2010-2011, First Semester

Written report

On

Output Devices

Prepared by:

Frondoso, Kenneth Raeneil B.

Gonzales, Je-Ann H.

Lasala, Lea B.


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Table of Contents

I. Introduction to Output Devices.

II. The Kinds of Output devicesa. The Monitor

1. Brief History of the Monitor

2. Kinds of Monitor

3. Parts of a monitor

b. The Printer

1. The History of Printer

2. Kinds of Printers

3.


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Introduction to Output Devices


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Kinds of Output Devices

a. The Monitor

1. The Brief History

Until the early 1980s most monitors were terminals. They were boxy video displayterminals (VDTs) combined with an attached keyboard. A terminal could be configuredto work with just about any computer on the market.

Terminals were attached to computers by a serial interface. In those days, the VDTwas commonly referred to as CRT(Cathode Ray Tube).

Before the DOS, the dominant operating system(OS) for 8 computers was CP/M(Control Program for Microprocessors). Early CP/M machines were originally designedto use separate memory-mapped video display devices and discrete keyboards thatplugged into the machines- not unlike video display cards used later. The most well-

known was the VMD-1. Terminal manufacturers recognized this lost market andbegan to market mainframe and mini-style terminal to the CP/M community. The salespitch of just like a real(mainframe at the time) computer paid off. CP/M computerssoon used terminals most exclusively.

Apple II computers and the early game machines(such as those made by Atari, colecoor Nintendo) hooked to a monitor not a terminal. The apple was built with a keyboardas part of the system. All that was missing was a monitor once the Apple II wasplugged in.

These monitors unlike terminals looked like television sets without the tuner. Insome cases they were actually television sets. Many computers- such as theCommodore Vic20, 64, and 128, could be used with any television set with a specialRF adapter that hooked to the antenna of the TV.

The IBM came out with PC-DOS computers, which are dubbed three-piececomputers. One explanation according to a prominent used car dealer MoonieBronstein was that many of the early marketers/ hucksters advising the techies of theearly computer era had their start in the competitive world of auto sales where suchterms as 3 piecers and four piecers were popular marketing and sales terms. Otherexplanations for this marketing term was because the computers included three maincomponents i.e.- the monitor, the keyboard and the CPU box.

Ironically, when the IBM PC-DOS computers arrived on the scene with separatemonitor and keyboard- the monitor connected directly to the computer. Just like theearliest personal computers through a display device connection. These new monitorsused video cards that were either IBM monochrome(MDA), IBM color graphicscards9(CGA), or Hercules (the first third party ad-on cards.)


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2. Kinds of Monitor

A computer display is also called a display screen orvideo display terminal (VDT). A monitor isa screen used to display the output. Images are represented on monitors by individual dotscalledpixels. A pixel is the smallest unit on the screen that can be turned on and off or madedifferent shades. The density of the dots determines the clarity of the images, the resolution.

Screen resolution: This is the degree of sharpness of a displayed character orimage. The screen resolution is usually expressed as the number of columns bythe number rows. A 1024x768 resolution means that it has 1024 dots in a lineand 768 lines. A smaller screen looks sharper on the same resolution. Anothermeasure of display resolution is a dot pitch.

Interlaced/Non-interlaced: An interlacedtechnique refreshes the lines of thescreen by exposing all odd lines first then all even lines next. A non-interlacedtechnology that is developed later refreshes all the lines on the screen from topto bottom. The non- interlaced method gives more stable video display thaninterlaced method. It also requires twice as much signal information as interlacedtechnology.

There are two forms of display: cathode-ray tubes (CRTs) and flat-panel display.

y Cathode Ray Tubes (CRT)

A CRTis a vacuum tube used as a display screen for a computer output device. Althoughthe CRT means only a tube, it usually refers to all monitors. IBM and IBM compatiblemicrocomputers operate two modes unlike Macintosh based entirely on graphics mode. Theyare a text mode and a graphics mode. Application programs switch computers into appropriatedisplay mode.

Monochrome Monitors

A monochrome monitor has two colors, one for foreground and the other for background.The colors can be white, amber or green on a dark (black) background. The monochromemonitors display both text and graphics modes.

ColorMonitorsA color monitor is a display peripheral that displays more than two colors. Color monitors

have been developed through the following paths.

o CGA: This stands forColor Graphics Adapter. It is a circuit boardintroduced by IBM and the first graphics standard for the IBM PC.With a CGA monitor, it is harder to read than with a monochromemonitor, because the CGA (320 X 200) has much fewer pixelsthan the monochrome monitor (640 X 350). It supports 4 colors.

o EGA: It stands forEnhanced Graphics Adapter. EGA is a videodisplay standard that has a resolution of 640 by 350 pixels andsupports 16 colors. EGA supports previous display modes andrequires a new monitor.

o VGA: VGA stands forVideo Graphics Array. This is a videodisplay standard that provides medium to high resolution. In a text


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mode, the resolution of this board is 720 by 400 pixels. It supports16 colors with a higher resolution of 640 by 480 pixels and 256colors with 320 X 200 pixels.

o SuperVGA: This is a very high resolution standard that displaysup to 65,536 colors. Super VGA can support a 16.8 million colorsat 800 by 600 pixels and 256 colors at 1024 by 768 pixels. A high-

priced super VGA allows 1280 by 1024 pixels. Larger monitors(17" or 21" and larger) with a high resolution of 1600 by 1280pixels are available. VESA (Video Electronics Standards

Association) has set a standard for super VGA.

y Flat Panel DisplaysPortable computers such as a lap top use flat panel displays, because they are more compactand consume less power than CRTs. Portable computers use several kinds of flat panelscreens:

Liquid-Crystal Displays (LCDs)

A display technology that creates characters by means of reflected light and is commonly usedin digital watches and laptop computers. LCDs replaced LEDs (light emitting diodes) becauseLCDs use less power. LCDs are difficult to read in a strong light, because they do not emit theirown light. Portable computers wanted to have brighter and easier to read displays. BacklitLCDsare used for the purpose now.

o Backlit LCDs: This is a type of LCD display having its own lightsource provided from the back of the screen. The backlit makesthe background brighter and clear, as a result the texts andimages appear sharper. However, this still is much less clear thanCRTs. Thus, better technology is needed.

o Active Matrix LCDs: This is an LCD display technique in whichevery dot on the screen has a transistor to control it moreaccurately. This uses a transistor for each monochrome or eachred, green and blue dot. It provides better contrast, speeds upscreen refresh and reduces motion smearing.

Electroluminescent (EL) DisplaysA flat panel display technology that actively emits light at each pixel when it is electroniccharged. This provides a sharp, clear image and wide viewing angle. The EL display type of flatpanel is better than LCD.

Gas Plasma DisplaysThis is also called a gas panel or a plasma panel and is another flat screen technology. A

plasma panel contains a grid of electrodes in a flat, gas filled panel. The image can persist for along time without refreshing in this panel. The disadvantages of the gas plasma displays arethat they must use AC power and cannot show sharp contrast.


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3. Parts of a Monitor

Most common parts to check

Ball links To check a link pull on it and see if it comes off. If it comes off with light

pressure or you see side to side slop of it on the ball then it is time to

replace it.

The links that wear out most often are the ones close to the ground. This

would be the one at the back of the tail control rod and the ones on the

throttle link. Note: If you put a new link on and it is still loose then what

happened is dirt got embedded into the old link and it wore down the ball.

You have to change both the ball and the link when this happens.

Fuel line inside

tankOne of the number one causes of engine tuning problems is from detoriated

clunk line. At the end of a flight the tank is full of hot exhaust gases that

break down the silicon fuel tubing. This makes the line soft and soggy. It

can also crystalize.


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A-arm rods Check the metal rod at the bottom of the A-arms. If the holes in the A-armsare tight it can cause the rod to eventually work its way out.

Rubberbands One is on the radio tray helping to hold the receiver and battery in place

and the other one to check is holding the antenna wire at the back.

Less common parts to checkBall Links

screwsIt has not happened to me but a few times, but sometimes when looking for

slop in the control system I have found the screw(s) that hold the balls on are

loose just enough that the ball moves on it.

Check pitch

armThe two screws that hold the pitch arm on can back out sometimes and cause

side to side slop.

Check

clutchIf you have the engine out and you notice the edge on the back side of the

shoes are not parallel to the straight edge of the hub then the clutch liner got

too thin and now you have to change both the liner and the clutch. Ideally you

should check the gap between the liner and the clutch shoes and when the gap

is more than 0.010" per side then replace the liner before the clutch isdamaged. If you do not have feeler gauges then take the start shaft out and the

clutch off. Place the clutch in the bell and push it to one side against the liner.

Next see if a business card will squeeze between the clutch and the liner. If it

fits loosely then replace the liner.

Muffler

boltIf you bought a Raptor 30 and are using the stock two or three piece muffler

then the long bolt that goes through from front end to back will become loose

from time to time. It's best if you tighten the bolt immediately after a flight,

while everything is still warm.

Muffler

boltsThe bolts that hold the muffler on have spring washers which lose their spring

when they get hot. This makes the muffler vibrate loose, resulting in a very

lean engine which can quit if you keep flying. (submitted by Gary Benade,thanks Gary :)

Carb nuts

and bolts

1. The nut that holds the main needle on the carburetor could be loose from

the factory.

2. Also check the nut that holds the throttle lever arm on.

3. And the bolt that holds the barrel in. It is the one that goes in at an angle.

Dirt in

plastic links

If you find a loose link and find the plastic link still snaps on another ball fine,

then suspect dirt in the plastic link. This grinds on the metal ball. Change both

the link and the ball.

Tail blade

grips

Check for slop in the tail blade grips on the tail hub. If it is very loose that is a

sign that the nuts or set screw going into the hub has backed out. If it is just alittle slop that could just be the fit of the blade grips on the bearings. If that is

the case you can sand a little off the inside of one grip and that will allow it to

squeeze closer to the bearings.

Rotor head

double linkA flying buddy had an in-air boom strike that we believe to be caused by the

double link on the rotor head breaking, so check yours for fractures caused by

a previous crash and make sure they fit on the ball good. If you can easily pull


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them off then you need to replace it.

Locknut

loose on the

main shaft

As part of your pre-flight check, make sure the bolt and locknut on the

bottom of the main shaft is secure. Note: do not overtighten or this will cause

the autorotation hub not to work. (tip came from Bob Cardone, thanks Bob)

Boltthrough

auto hub

I found this bolt was broke in 3 places on a crashed Raptor of a friend ofmine. I helped him put the crashed Raptor back together then we flew a tank

through it and while fueling up again, we found the head of this bolt was gone.

A section of threads and another section of threads with the nut on it was all

that was left. This very easily could have caused another crash. So after a

crash or hard landing check this bolt. Also make sure the bolt is not tightened

too much. This will help cause the bolt to break.

Start shaft

bearing

block

After 534 flights Raptor #1 had worn out the start shaft bottom bearing block.

My guess is the bearing got too much dirt in it and eventually locked up

causing the bearing to rotate in the bearing block. It melted the frame and

covered the bearing with a coat of plastic.

Gyro tape I regularly check this by slightly pushing on the gyro to see if the tape tries toseparate. I typically have to replace the tape that came with my Futaba gy401

gyro about every 500 flights using 15% nitro fuel. If you fly 30% then it will

greatly shorten the lifespan of the tape.


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b. The Printer

1. The Brief History


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Documents

Written Report ICT