INDEX ƒ TEXT ƒ MONITOR 3ƒ LETTER Jƒ PARTS N ƒ MODERN Wƒ TEXT TEXT WORK FILE BYPP MONITOR MONITOR BYPP LETTER COVER LETTER BYPP PARTS PARTS LIST BYPP MODERN LETTER BYPP @ @ Have you marveled at the quality and clarity of the new @color video monitors that have appeared on the market and @been envious of the people who can afford their high price @tags ? Well, thanks to a single integrated circuit, eight @transistors, a handful of small parts, and a little old- @fashioned horsetrading, a color video monitor rivaling the @commercial units can be had for a fraction of the cost ! @ @This monitor can give you an incredible color picture via @the composite video signal from your VCR,video disc player, @home color computer(Radio Shack, Commodore64, Colecovision, @Atari,etc.) or satellite dish receiver. If you need audio, @use the audio amp described here, or, in the case of a VCR, @disc player, or satellite receiver, use your home stereo @system. Most color computers on the market today have @separate video and audio outputs. @ @ The decline of the arcade video game business because of @home computers and home video games is a boon to @the electronics hobbyist. Flea markets, distributors, auc- @tions and foreclosures have put these arcade video games on @the market for a fraction of their original cost--sometimes @as low as $25 a game. Inside these games is a wondrous @parts bonanza for the experimenter--just about everything @needed for a high quality color video monitor and then @some . @ @ The first step in our project is to get one of these @arcade video games. The reason we want a video game @monitor rather than the guts from a used TV is that these @monitors have special picture tubes and associated elec- @tronics which give them much better color dot resolution @and wider bandwidth (a home TV has a bandwidth of 3-5 Mhz; @a video game monitor has up to a 15 Mhz bandwidth). @ @ Probably the least expensive source is an auction or @foreclosure sale. Surprisingly, many auctions are @held in major motels in large cities. An eye on the news- @paper or a tip from a local video game distributor may @provide the clue you need. Go with cash in hand and, un- @less you count on tearing it down in the parking lot, a @truck. Video games are heavy and bulky . Since these guys @don't want to take them back, you'll probably be able to @negotiate the price. Flea markets occasionally have arcade @video games, but usually at higher prices. Sometimes the @people selling a working game may have a nonworking one @stashed somewhere. The same goes for your local video game @distributor. Take the time to find just the right one to @suit your needs. These monitors are well designed and will @take much more abuse than your home TV. Don't worry if the @game doesn't play (usually the video electronics go bad), @but be sure the monitor has a raster. Expect to pay $25 - @$100 . The video games come in a variety of sizes and @shapes--some upright, some sitdowns ("cocktails", in the @trade). All have 13" or 19" monitors(either sitting side- @ways like a regular TV or vertically--it doesn't matter @except for mounting) made by Electrohome, Wells- @Gardner, Disco, Nanemco, etc. All are basically the same. @Be sure to get a "raster scan" monitor (which scans like a @TV) as opposed to an "X-Y or quadrant" monitor. About 90% @are raster scan. Usually X-Y monitors give themselves @away by having a burn spot in the center of the screen or, @if working, only half a picture vertically or horizontally. @Try to get a monitor that doesn't have a faint outline of @the old game on it--the phosphors get burned with long use, @although this outline will gradually fade with use and @time. @ @ Once you get the video game home, you may as well dis- @assemble it in the driveway or garage. Take what you need @and junk the rest! Here's what you want and how to get it. @ @1. The Monitor-- @.DEL @ a.The monitor is usually powered by a cord running to an @ isolation transformer or to the power supply--unplug @ or clip this lead. @ b.Clip the 5 or 6 smaller wires going to the monitor, @ leaving them as long as possible--usually they are @ colored red, green, blue, white or yellow, and black. @ c.The picture tube neck and neck assembly are very @ fragile. Wear glasses and handle with care! @ @2. The Power Transformer-- @ a.There may be one main transformer or separate ones--if @ there is more than one, determine which is the monitor @ isolation transformer. You MUST use an isolation @ transformer. Either use the one in the cabinet or get @ a 110VAC:110VAC, 1 amp isolation transformer(see Parts @ List). But if you should find one huge transformer on @ a chassis, you should still opt for the isolation @ transformer. The huge transformer draws alot of @ current to derive voltages you don't need although it @ does have the necessary isolation. There may be a @ switching power supply with a separate isolation @ transformer which you may want to save. @ @3. The line cord, fuse block, and EMI filter (if there is @ one) can be used. The flourescent light and speaker @ come in handy for other projects. There are few, if @ any usable parts on the large PC board(s). You may want @ to save the bezel (if there is one) and some of the @ particle board for later construction of a cabinet. @ Now that you have your monitor, let's look at our simple @RGB (red,green,blue) Decoder. A look at the block diagram @will give you an idea of the signals we need from our com- @posite video signal and how they are used (see Fig.1). The @heart of our decoder is a 28 pin marvel of a chip. It is @available as a UPC 1352, UPC 1372, SK 9016, or ECG 1416. A @.DEL @detailed description of all its attributes would take many @pages, but suffice is to say that it automatically corrects @brightness, contrast, clarity, color, and tint. Although @we have allowed for external control of these functions, @the only necessary external control may be tint to allow @for the occasional off color tape in a VCR. Otherwise, @set it and forget it. Since the chip has an on-board reg- @ulator, we use it for the rest of the power requirements @as well. There are no real tuned circuits to worry about. @The eight transistors are used in various configurations to @derive the necessary drive signals for the decoder chip and @monitor from the composite video. These include chroma, @sync, luminance, and blanking. The use of a PC board is a @big help although layout (other than short leads) isn't @critical. I was able to make my decoder for about $35 . @All parts are standard, off-the-shelf items, and can be had @from the suppliers listed (see Parts List). @ @MONITOR CHECKOUT AND SET-UP: @ @ If your monitor hasn't been adjusted since it became a @video game, little or no readjustment is necessary. It @can be checked easily. Be sure you have an isolation @transformer in place. @ 1. Of the five or six small wires coming from the mon- @itor, temporarily ground the red, green, and blue ones to @the black wire. You should have a uniform gray raster. If @you do not have one, then carefully adjust the blue and @green drive pots on the neck PC board to get a gray raster. @ 2. Separate the red, green, and blue wires and alter- @nately put a flashlight battery (1.5-3VDC), minus end to @black and plus to colored wire, and adjust the red, green, @and blue cut-off pots on the neck PC board to get an equal @amount of each color on the screen. @ 3. Adjust the screen control (may be on the neck PC @board or under the focus control near the flyback trans- @former) until the raster is barely visible. @If you feel uneasy about or don't understand this pro- @cedure thoroughly, I recommend you take your monitor to a @service shop or technician and have him do it. Remember @that these monitors use very high, deadly voltages. Don't @disturb the yoke assembly or the series of magnets behind @it since this will throw color purity and dot convergence @off. Since the isolation transformer can also upset the @purity and convergence, it's best mounted outside the @monitor chassis. Many new-design isolation transformers @(see Parts List) come with Mu-metal shields and can @successfully be mounted inside the chassis but away from @the picture tube. The decoder board can be mounted @anywhere inside or outside the chassis. @ @DECODER TUNE-UP: @ @ Tune-up is simple. Hook up your decoder referring to Fig. @2. Set brightness, contrast, tint, and video gain to mid- @point; color and chroma, fully counter-clockwise. Alter- @nately adjust video gain, contrast, and brightness for best @black and white picture, paying attention to highlights and @picture detail. Adjust color and chroma to full CW to be @sure you have color, then adjust color, chroma, tint, and @the trimmer capacitor for best color. @ @ADDING AUDIO: @ @ The easiest way to add audio is through a stereo system @since the sound quality will be vastly improved, especially @if you are using a VCR, disc player, or satellite re- @ceiver. A computer can use any external audio amplifier @or the one described here. Use the 15VDC from the decoder @board or a separate power supply. @ @CONCLUSION: @ @ The enhancements that can be made to this basic project @are limitless. For the advanced experimenter, the addition @of a stereo decoder or the construction of a complete @component video system including a separate tuner are @easily and reasonably within reach. My own system has two @monitors--one for the two VCRs and another for a component @TV using the famous Zenith 9-151-03 tuner-IF-video-audio @module. The picture quality and color purity is truly @amazing! @ @ @ @ @ @ @ @ @ @September 10, 1985 @ @ @Mr. Art Kleiman @Radio-Electronics Magazine @Gernsback Publications, Inc. @200 Park Avenue South @New York, New York 10003 @ @Dear Mr. Kleiman, @ I have had this article written for several months, but @was dismayed by Neil Heckt's article in the August and @September, 1985 issues of Radio-Electronics due to their @similarities. I felt compelled to submit mine since it @has a different approach to the subject. My way is less @expensive, and since most VCR's, disc players, and @satellite receivers already have comb filters, much easier @to build. Computer generated video has little use for a @comb filter. @ It is with these thoughts in mind that I enclose this @article for your consideration. I think it would be a @fine addition to your already great magazine. @ @Sincerely, @ @ @Michael Anderson @4150 Pembrook Place Suite 315 @Austintown, Ohio 44515 @1-216-793-8034 @Resistors: (All 1/4 W, 5% unless indicated) @.DEL @R1 91 ohms @R2 500 ohm trim pot @R3, R21 68 K @R4 12 K @R5, R46, R47, R48 270 ohms @R6, R44, R45 1 K @R7, R9, R18 100 ohms @R8, R19 560 ohms @R10, R28, R34, @R37, R40 10K trim pot @R11, R32 150 ohms @R12 470 ohms @R13 6.8 K @R14 5.6 Megohms @R15 75 K @R16, R22 2.4 K @R17, R25 1.8 K @R20, R23 10 ohms @R24 3.9 K @R26 100 ohms, 1 Watt @R27, R30, R31, R38, @R41, R42 10 K @R29, R35, R39 30 K @R36 47 K @R43 220 K @ @Capacitors: @.DEL @C2 68 pf disc @C1, C3, C8, C9, C10 @C12, C13, C14 10 uf, 16 VDC electrolytic @C4 .33 uf Mylar @C5 150 pf disc @C6 100 uf, 25 VDC electrolytic @C7 .1 uf disc or Mylar @C11 33 pf disc @C15, C26, C27, C28 100 pf disc @C16 390 pf disc @C17, C18 .01 uf Mylar @C19 1uf, 16 VDC electrolytic @C20 4.7 uf, 16 VDC electrolytic @C21, C22, C23 .22 uf, 16 VDC electrolytic @C24 39 pf disc @C25 4-34 pf trimmer capacitor @C29 2200 uf, 25 VDC electrolytic @ @Miscellaneous: @.DEL @T1 12 VAC, 120ma. transformer (Radio Shack 273-1360 @BR1 1 Amp Bridge Rectifier (Radio Shack 276-1161) @F1 .5 Amp fast blow fuse and holder @D1 1N914 silicon diode @Q1 2N3904 transistor @Q2 2N3906 transistor @Q3-Q8 2N3904 transistor @U1 UPC 1352, UPC 1372, SK 9016, ECG 1416 decoder @X1 3.58 color burst Xtal (Radio Shack 273-1310) @ 28 pin DIP socket @ 110 VAC:110 VAC, 1.2 Amp. Isolation Transformer @Available from: The Wireless Works @ 4150 Pembrook Place Suite 315 @ Austintown, Ohio 44515 @ $27.00 ppd. @.DEL @.DEL @.DEL @ @November 20, 1985 @ @Mr. Art Salsberg @Modern Electronics @76 North Broadway @Hicksville, New York 11801 @ @Dear Mr. Salsberg, @ I am submitting an article for your consideration to be @included in your new magazine, Modern Electronics. I had @previously submitted it to Radio-Electonics. I enclose @copies of my cover letter and their return response. @ Since writing the article, I have made several proto- @types and have had more than favorable response regarding @color, clarity, and resolution. Although money is avail- @able to "kit" the unit, I've been a hobbyist for some 30 @years. I would rather share my creation with others who @are just getting started in our great hobby. Popular @Electronics, Radio-Electronics, etc. have lost sight of @the needs of the hobbyist. @ @Sincerely, @ @Michael E. Anderson @4150 Pembrook Place Suite 315 @Austintown, Ohio 44515