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This will work with any IBM type monitors (the ones with digital RGB), or Monitor/TV combos (a la Panasonic Omni and others), or whatever. Be SURE you have _c_m_p_l_e_t_e technical knowledge. I'm not just talking about digital electronics and wiring, folks. If you stick your finger in an ST, maybe you'll blow a chip or two from static, and if it's powered you might get a nasty shock (come on, now, you DO hold your other hand away from ground, don't you?). When working inside any CRT device (TV Set, Monitor, whatever), if you hit your hand where it isn't supposed to be (EEVVEENN IIFF IITT''SS OOFFFF), you could very well get 20kV at several mA (yes, that's 20 _t_h_o_u_s_a_n_d volts). The current is easily enough to kill you. The reason for this is that any CRT (Cathode Ray Tube) acts like a capacitor (it is physically similar to a Leyden Jar except much more efficient). The high voltages have been known to remain for up to a _m_o_n_t_h after last use. I repeat (and I can't repeat it enough) -- if you don't feel confident working with deadly voltages, don't work on this! You won't be actually working in the high voltage section, but one slip and you're in a lot of trouble! I take _N_O responsibility for any damages to you, your ST, your monitor, or anything else. I would STRONGLY recommend that you get schematics for your monitor (and in fact I'm assuming you already have). But, if you can't or are feeling brave/foolish/suicidal, I'll describe how to guess your way along, so go ahead. After all, it's not my monitor. Also, read through this entire file (even if part of it doesn't apply to you) before doing anything. It might save you a lot of grief. SSAAFFEETTYY PPRREECCAAUUTTIIOONNSS AANNDD SSUUGGGGEESSTTIIOONNSS 1. When working with any high voltages (or whenever in question), either keep one hand behind your back or in the air, or wear rubber gloves. This will prevent any voltages from going across your chest via your cardiac muscle. 2. Wear rubber soled shoes and work on carpet or wood or linoleum, but not concrete if you can help it. 3. Keep everything (including you) dry. 4. NNEEVVEERR I repeat NNEEVVEERR use stranded wire inside any electronic device. Stranded wire is meant for cables and longer wires -- not for jumpers or modifications. If so much as one strand comes loose during operation or construction, you can do anything from burn out a minor chip all the way to sending 45,000 volts into your ST. 5. If in doubt about working with the high voltages inside the monitor, don't do it. Get a friend or a professional to help. 6. If you don't want to work with the anode voltage present (that's the high voltage that stays around so long) and know how to handle high voltages, then drain the anode voltage (see below, DRAINING THE ANODE VOLTAGE). 7. Work in a low-static area, or wear an anti-static armband (yes, I know it's uncomfortable). 8. Do soldering in a ventilated area. The smoke from solder contains burnt rosin, which many people think smell bad (though frankly I kind of like it). More importantly, I recently learned it also contains lead vapor (hmm ... maybe that's why I've been a bit slow recently). 9. If you've never soldered electronics, use rosin-core solder, and practice about a year before trying any project like this one, and in the mean time, why are you reading this? 10. Use only a low-powered soldering iron, and either run from battery power, or ground the soldering iron tip, or if all else fails at least plug the soldering iron into a surge-protector. 11. Avoid touching the CRT. Aside from high voltages, you could break it. Most CRTs now have implosion protection to keep shards of glass from flying into you, but CRTs are _v_e_r_y expensive, so it's best not to break them. 12. If you get frustrated by a problem, take a break and clear your head. I've had plenty of problems that were unsolvable until I stopped pounding my skull trying to solve them. WWHHAATT WWIILLLL WWOORRKK AANNDD WWHHAATT WWIILLLL NNOOTT I'm going to assume that you've tried out your ST with the monitor in unmodified form and gotten at least some sort of output that isn't an analog output and can't be made analog through the brightness and contrast controls. See the appendix section for pin connections for IBM monitors. If you haven't checked the monitor for compatability, do so. If you don't get an output at all, then tweak the brightness and contrast and go through the monitor instructions again. If it still doesn't help, you can go ahead anyway, but I won't guarantee that the monitor is modifiable. Of course, if the monitor works as is, there is no need to do anything. So far, I've either verified myself or heard second hand that all IBM digital RGB monitors can be converted. But DON'T go out and buy a monitor without checking out the schematic. What your monitor needs to have is an input which feeds from the RGB connector to some digital logic gates, and then into a series of analog (transistor, resistor, op-amp, etc) circuits and _n_o_t back into digital IC's. For those unfortunate souls out there without schematics, digital IC's will usually be 74nnn, 74Snnn, 74LSnnn, 74Cnnn, or 40nn. Analog chips can be anything, but you're most likely to see op-amps (741, 1458, LM3900, TL084C, etc.) or comparators (LM339 is most common). By the way, you should know all of this (if you don't, you're most likely getting in a little too deep). For the purpose of this explanation, if you find a comparator in your signal path, consider it a digital chip. It probably acts as such. One other chip type you may find is what's called a "silicon switch" or a "bilateral switch", and is common with TV/Monitors or with monitors that accept both composite and RGB (or any two different types of inputs). I've seen the 4053 and the 4066 used for this. If it's anything else, check in a reference book. It's an analog chip, not a digital, and will rarely have to be bypassed or replaced. OOPPEENNIINNGG TTHHEE MMOONNIITTOORR Now that that is out of the way, we can safely proceed to the actual modification. First, unplug your monitor and let it sit for at least 1 hour. This won't get rid of the CRT charge but it will reduce it, and will also get rid of normal capacitor charges. If it's a TV as well as a monitor, short the 300 Ohm inputs together briefly, and the cable input (use an unbent paper clip; push one end in the center and touch to the shield contact). The reason for this seemingly idiotic little procedure is that some TV's with hot chassis that I've worked on seem to keep a charge at their cable inputs. By the way, make sure you don't short them yourself (as in with your hand). Once you've gotten rid of any spare charges, you are ready to proceed. Remove any face plates on the front of the monitor. If there are any buttons or knobs that pull off (give a small tug and they should pop right off), do so now. Put the monitor face down onto a THICK carpet at table level (ie where you have to stand to work at it). Locate any screws (use a flashlight if you can't see them) and use an appropriate screwdriver. If the 'screws' have hexagonal holes, you can get hex drivers at most hardware stores. If they have square holes, good luck! If you can't find quad drivers at hardware stores (it's a European standard, I think), you can try a regular screwdriver placed in diagonal to the square. Remove the screws. Carefully lift up the top. If it won't go, check for screws you haven't found. If it still won't, see if there are any panels or cords on the back that disengage from the back cover. If it's heavy, then you're probably pulling the CRT back too. In that case, put the cover back on, and tip the entire monitor so that it is in normal position (front facing front, top facing up, etc), and try pulling the front off. Once you get the cover off, familiarize yourself with the internals. Locate the CRT and look at it well. You should see an "anode cup" which sits on the CRT's top or side or bottom, but not at the end or neck (the neck is the narrow part where most of the wires attatch to the end). The anode wire traces back to the flyback transformer. This is the place you want to avoid. The anode wire is usually insulated heavily, but don't count on the insulation to always work. Ozone from high voltages will erode and crack most insulations. DDRRAAIINNIINNGG TTHHEE AANNOODDEE VVOOLLTTAAGGEE If you feel _c_o_m_p_l_e_t_e_l_y safe avoiding the anode area, skip this section. Otherwise, you will want to ground the anode voltage. Take a heavy wire, and clip one end to the chassis. Put a 500 K high power resistor (10 watts or so) on the other end. Put a 120 volt neon lamp (available at Radio Shacks) in series with this resistor. Then connect another wire to the other side of the neon lamp, with a probe at the other end. Make sure the resistor is away from you or anything else conductive. If you can take the cup off easily and with confidence that you won't touch anything, do so. If you can, then ground the anode lead from the flyback transformer first, then touch the probe to the inside of the hole where the anode lead used to fit. If you didn't remove the anode cup, then stick the probe under it and move it until it hits the metal piece. When you touch the probe to the CRT itself (or the anode cup if it's still in place), the neon lamp should flash rather brightly (by the way, it might not be useful after this, so feel free to use one from your junk box). If it doesn't flash, scrap the neon light and just connect your probe to the resistor and try again. You won't be able to know when you've made contact, so you'll just have to trust your instincts (and any sparking noises you hear). Replace the anode cup, and you're all set and much safer. If you don't want to do this yourself, ask any TV technician to do it for you -- you can take your monitor in, have him drain the anode voltage, and then take it back and work on it. RREEMMOOVVIINNGG TTHHEE CCIIRRCCUUIITT BBOOAARRDD To do any soldering, you will need to either have easy access to the bottom of the circuit board, or remove it. The circuit board in question is the one where the RGB connector goes to first. If you can get to both sides of the board easily, fine. Just make sure you aren't going to be bumping into the CRT or high voltage section (usually noticable with thickly insulated wires), and you will most likely want to drain the anode voltage (see previous section). I recommend you remove the circuit board. First remove any screws that may be in place, taking care to catch them and any nuts that may be behind them. Next, check to see of the board is "hard-wired" to anything else. If you can take out the board simply by unplugging connectors, you are fine. Remember to mark the connectors so you'll know what goes where. If you have wires that are actually soldered into the circuit board you want to remove, try tracing them to their destination. Chances are they have connectors there; if so, mark them and remove them. If not, just try and give yourself a lot of room without tugging on the wires. If you still don't have much space, you'll have to desolder the wires temporarily and resolder them when you are done. Again, mark them. TTRRAACCIINNGG TTHHEE CCIIRRCCUUIITT If you have no schematic, you'll have to follow the circuit by looking at the monitor. If you do have a schematic, follow through using the schematic and not the monitor. What you're trying to do now is to find out what chips in the RGB input section you'll have to get rid of or bypass. First, find the three wires that come directly from the R, G, and B input pins; for an IBM monitor with an 8-pin connector, see the diagram below. Always check the monitor manual -- it may be different from what you expect. I'm going to describe ONE signal path (in this case Red, though it doesn't matter which). But trace them all -- a sure indication you've lost your place is that things start to look too different between them. SCENARIO ONE: TYPICAL This is the most common signal path I've found, so I'm including it first. If you don't have this type, don't worry; I describe several others. The first thing you'll see is probably a resistor of about 100 ohms separating the connector line from the rest of the circuit. This helps to keep circuit drain from getting too high. Next you'll find a pulldown or pullup resistor of about 1K. A pulldown resistor connects to the line and to ground, and a pullup resistor connects to a line and to a positive voltage supply. They define what state the line is when there isn't any input). Neither of these must be there; but they usually are. You may also see a zener diode connecting the signal and ground; this simply keeps the voltage input from becoming too high. A zener diode usually looks like any other diode; there may be a voltage printed on it. Next the signal will probably go into some kind of level correction chip. It will be a digital chip, quite possibly a 7409 or 74LS132. Check with a IC reference guide. You should see the words "schmitt trigger" or "level correction" in the description. If you don't, it really doesn't matter now, but if you feel up to it, write the monitor manufacturer a nasty letter for me. If it isn't a schmitt trigger, it'll probably be a gate of some kind. Most likely it's an AND gate, a NAND gate, a NOR gate, or a buffer. Check with the diagrams for pin outputs. Trace the other input to the gate. If the gate is an AND or NAND, it should go to either a voltage supply or the first input (ie both inputs are connected). If it's an OR or NOR, it should go to ground or to the first input. If it's a buffer or a NOT gate, it has no other input. And if it's an XOR gate, you've read your chip numbers wrong. At this point, trace the signal out of this gate. It should go to some transistors or Op-Amps. If it goes into more digital chips, keep following until it exits the digital chips and enters the transistors or op-amps. If you don't find any transistors or op-amps, you've probably lost your way. If you still don't find any, then I suggest you consult the schematic. You need to find the exact point where the signal exits the digital section and enters the analog. This may be accompanied by a change in circuit boards (if so, you're in luck, but I doubt it will). This is the point where you will be inserting your new circuitry. SCENARIO TWO: LESS COMMON It is possible that right after the isolation resistor and pulldown/pullup resistor, you find a transistor or Op-Amp or two. Just ignore these and follow the signal until it gets to digital chips like those described above. SCENARIO THREE: UNCOMMON I've never seen this one but I've heard it can exist. Instead of using digital chips to make the signal level correct, some monitors use comparators. If you find a comparator early on in the signal path, chances are it's being used for this purpose. Consider it the same as a level correcting digital IC. SCENARIO FOUR: ANYTHING ELSE If you're completely lost, E-mail me a letter describing your schematic. My ID number is 71451,755. PPRROOCCEEEEDDIINNGG WWIITTHH TTHHEE MMOODDIIFFIICCAATTIIOONN The first step you have to do is to trace all three (R, G, and B) signals and verify you've got it right. They should all go into the same level correcting IC, and that IC will probably have one unused gate. Check the inputs and outputs on that gate. If the output is not connected, or if the inputs go to a voltage source or ground, then you can safely remove the IC. Otherwise, it's probably got a secondary function. Remove the chip. If the chip is in a socket, you're in luck. If not, desolder the chip and then scrap it. Desoldered chips are often dead and almost always damaged. If the chip has a secondary function, buy a new one at Radio Shack or mail order. In the mean time, solder in an IC socket where the chip was. Solder in three jumper wires to let the signal pass through where the IC's gate was. Solder one end of a jumper where the signal comes in, and the other end where the signal goes out. Always consult an IC pin diagram to make sure you aren't shorting anything out. Also remember to solder onto the BACK (where the circuit traces are), and note that the IC pins are going to be backwards (ie what was on the left with the IC facing up is now on the right with the IC facing down). For jumper wire, I suggest the type used in making prototype breadboards. If you need to re-insert the chip because of a secondary function, then bend back all the input and output pins for the R, G, and B signals. Plug the chip back in. TTAAKKIINNGG CCAARREE OOFF TTHHEE IINNTTEENNSSIITTYY PPIINN There's one more thing that must be done. There is an "intensity" pin on all IBM monitors which controls whether the selected color is normal or dimmed (which is what allows the IBM to get 16 colors, not 8). This has to be taken care of, or your colors will all be dim (or worse). There are two ways to take care of your problem. The first, best if you don't like to do a lot of wiring, involves wiring the intensity pin to a 5V supply. Simply locate a 5V supply. A 5V supply will connect to the voltage supply pin of any 74nnn (or 74Snnn or 74LSnnn) IC. Follow the 5V supply to a suitable place where you can attatch a small wire. For this use I suggest "wire wrap" wire available at Radio Shack stores. Strip using your fingernails or a wire wrap stripper, but never with a knife or wire strippers. Solder one end to the 5V supply, and the other end to the intensity pin on the connector. A slightly better version of this involves soldering a 1K resistor in series with the 5V supply. If you have space, then do this. Solder from the 5V supply to the resistor, and from the resistor to the intensity pin. Remember to insulate all the connections; in fact I suggest slipping a piece of heat-shrink tubing over the resistor and its leads, and then shrinking it to cover all exposed bare wire. The second method, which is better but involves more wiring, requires you to trace the intensity signal until it splits into three signals. These three signals (one for red, one for green, one for blue) should go either to transistors or to resistors. Taking red as an example, what we need to do is disconnect the lead of the resistor (or transistor) that attatches directly to the intensity signal. Then, solder a new wire onto the resistor or transistor lead that you now have floating in air. Connect the other side of this wire directly to the R input on the connector. Of course, for green and blue intensity signals, you want to use the G and B inputs, respectively. CCLLEEAANNUUPP Make sure that all leads that are "floating" are insulated. Check all soldering for sharp points and solder bridges. Solder bridges (solder which shorts two separate signals) may be corrected by heating the bridge to melt and then sliding a piece of thin, stiff paper between the two signal points. Check the surface where you soldered in the IC socket. It should be smooth and not too big. If you can get it, put a piece of adhesive foam onto it, so as to protect any components underneath. RReemmeemmbbeerr ttoo rreeccoonnnneecctt tthhee aannooddee ccuupp to the CRT if you disconnected it!! TTEESSTTIINNGG TTHHEE MMOODDIIFFIICCAATTIIOONN At this point, it's time to test the monitor. Re-assemble the cover of your monitor, putting everything back. Disconnect the monitor cable. Power up the monitor, and using a voltmeter, check the R, G, and B inputs on the monitor. If ANY of them show voltage, check the current with an ammeter. If the current is above 20 mA, you've got a problem. You CAN use diodes to make sure that the voltage only flows into the monitor, but I'd be more inclined to go back over my wiring and make sure I didn't do something wrong. If everything checks out OK, then plug in the monitor cable, turn on the monitor, and power up the ST. You should get a screen of some kind. Now, go to the control panel, and make the colors various shades of grey. Adjust the color and contrast on your monitor for the best variation of shade. If you get a good range of brightness, the black should be completely black, the white should be bright, and the greys should blend smoothly. If you don't see the darkest grey (color 111), don't worry; you probably won't with an ST monitor anyway. If it isn't the right color, don't worry either. For now you are concerned with the luminance, not the color. If your brightness range is good, you can correct any color problems by skipping to the section marked CORRECTING COLOR BALANCE. IIFF IITT DDOOEESSNN''TT WWOORRKK PROBLEM: The colors "cut off" too soon. Using the control panel, the higher RGB colors (such as 777, 666, and 555) have different brightness, but the lower colors (such as 111, 222, and 333) are all black or very dark (no interference lines). CAUSE 1: The contrast is too high. SOLUTION: Decrease the contrast and increase the brightness. CAUSE 2: There is some kind of comparator in the signal path, which is 'killing' the signal if it falls too low. SOLUTION: Bypass the comparator, like you did the level corrector. CAUSE 3: Intensity signal is making response nonlinear. SOLUTION: See section below, INTENSITY SIGNAL CORRECTION. CAUSE 4: Response is nonlinear for other reasons. SOLUTION: This one is difficult. Trace the signal and look for several transistors in the signal path after the (former) digital section. If there are several in a signal path, then you can try bypassing one by desoldering it (taking care because you may have to replace it), and replacing it with a jumper. To do this, you MUST have a schematic to know where the output is (it might be the emitter or it might be the collector). If this fails, then the only thing I can suggest is to replace a transistor with an op-amp, which requires some more work. See the schematics for details on how to do this. In any case, do NOT remove any power transistors! PROBLEM: The darker colors have curious interference fringes or patterns, usually looking cross-hatched or specked, and the pattern often jumps around rapidly. CAUSE 1: There is signal interference due to outside equipment. SOLUTION: Make sure your monitor cable is short, and preferably shielded. CAUSE 2: There is internal interference; jumpers are too long. SOLUTION: Keep the jumper wires as short as possible. CAUSE 3: There is internal interference from an IC with bent-back pins. SOLUTION: Connect the bent-back input pins of the IC together, and then connect them to ground. CAUSE 4: Something in the signal path is unstable. SOLUTION: If this problem only occurs with one color (for instance, the red but not the green or blue), replace the components near where you soldered for that particular color. If the problem occurs with all colors, then your problem is more complicated, which brings us to: CAUSE 5: Signal components themselves are unstable. SOLUTION: Select a color that you know has interference lines. Set the entire ST screen to that color (foreground, background, and all intermediate colors). Using an oscilloscope, check the signal as it passes through the TV. Note that this requires working on the TV while it is powered up, so do nnoott attempt this unless you know what you are doing! When you find the place where the signal changes from a smooth one to a spiky one, you have found your bad component. Chances are that it is digital. If it is, bypass it. If it isn't, E-mail me (I'm 71451,755) and tell me what it is. I'll work on it. CAUSE 6: Intensity signal wiring is unstable SOLUTION: See INTENSITY SIGNAL CORRECTION below. PROBLEM: No picture. CAUSE 1: Cable is miswired. SOLUTION: Verify cable wiring with ohmmeter or continuity tester. CAUSE 2: Jumpers are improperly placed. SOLUTION: Check jumpers CAUSE 3: "Unused" gate was actually used. SOLUTION: Reconnect removed IC(s) "unused" gate by bending back the pins as described above. CAUSE 4: Contrast and/or brightness are misadjusted. SOLUTION: Adjust contrast and brightness. PROBLEM: Color levels "bleed"; in other words, if you set full red (700), it has green and/or blue in it, whereas black (000) doesn't. CAUSE 1: Solder is "bridging" two pins on the IC socket. SOLUTION: Check soldering. If a bridge is present, heat up the bridge and run a piece of paper between the two pins to separate the solder bridge. CAUSE 2: Intensity signals miswired. SOLUTION: Check to see that the intensity signal for Red goes to the R input, and so on. PROBLEM: One or two of the three colors are absent. CAUSE 1: Jumpers are not making connection. SOLUTION: Check jumper soldering. CAUSE 2: Soldering damaged other components. SOLUTION: Replace any components in doubt. PROBLEM: Vertical or horizontal sync is missing. CAUSE 1: "Unused" gate in removed IC was actually used. SOLUTION: Replace IC, with color signal pins bent up, as described below. CAUSE 2: Components for sync circuit damaged by soldering. SOLUTION: Troubleshoot yourself and replace damaged components, or get monitor repaired. PROBLEM: Entire monitor failure (will not turn on, or performs erratically). CAUSE: Wire and/or solder has bridged signal lines. SOLUTION: Examine monitor for stray wires and/or solder bridges. Remove all. CAUSE: Permanent damage to monitor. SOLUTION: Troubleshoot yourself if you have the equipment (a good oscilloscope is necessary), or have repaired. PROBLEM: Computer doesn't work, and won't work on an ST monitor after your test of the modified monitor. Key click is still heard, and disk still boots. CAUSE: Computer has been damaged (most likely VDG chip). SOLUTION: Have computer video circuitry repaired. PROBLEM: Same as above, except no key click and no disk access. CAUSE: Entire computer has been damaged. SOLUTION: Scream, swear, cry, and/or give up. IINNTTEENNSSIITTYY SSIIGGNNAALL CCOORRRREECCTTIIOONN It is possible that you are having problems because of the way your monitor interprets the intensity signal. After all, it is entirely possible that your monitor was not designed to respond in a linear fashion to input voltage, because nobody really wanted it to be linear in the first place. If your brightness levels look "funny", or the colors don't increase in brightness evenly, this might be the problem. First, make _s_u_r_e that you've tried changing the Contrast control. Nonlinearity can usually be fixed this way. If the problem isn't nonlinearity, or can't be fixed that way, then you'll have to do this. You need first to remove the jumpers that bypassed the old digital IC. The next step depends on whether that chip was a comparator or a logic gate IC. If it was a comparator, first plug it back in. Then, find the resistors that define the reference voltage. Remove any one of the three resistors and connect two long wires into the holes where this resistor was. Connect a variable resistor of similar value as the old one onto the two wires. What you now have is a "remote" resistor. Replace the cover loosely, and bring the variable resistor out where you can work at it. Connect your ST to the monitor. Select whatever color you replaced the resistor for. Tune the resistor until any problems disappear. If they don't disappear, E-mail me a description of your problem. Once you determine the proper resistance, get a resistor as close to that value as you can and replace the old resistor with it (removing the remote wire, of course). Do this for all three colors (R, G, and B). If it wasn't a comparator, you've got work to do. You have to build a "piggyback" board. I'm including in the schematics a simple drawing and schematic for this board. Essentially, you must first remove the IC socket you put in (or one that was already there) where your jumpers were. Then, get a small circuit board (I suggest Radio Shack) about 2 inches square, and with no circuit traces -- only copper "donuts" where the holes are. Get a wire wrapping IC socket (it's an IC socket with very long pins). Solder it onto the circuit board you bought, copper side of the board facing away from the socket and towards the end of the pins. You will be plugging _t_h_i_s into the old location of the IC on the monitor circuit board. Wire up the schematic on that board. Then, if you need to, put the original digital IC into the wire wrap socket. Make sure your circuit is correct. Cut out a cardboard (the stiff solid kind, not corrugated) sheild slightly larger than the board you bought. Push it onto the board, letting the pins of the wire wrap socket protrude through. This will insulate the board from the monitor circuitry. Push the wire wrap socket's pins into the holes in the monitor where the IC was, taking care to make sure it is in correctly. Solder it in place, and clip off the excess leads (but make sure they don't fall into the monitor!). You are now finished -- good luck getting the case back on over your piggyback board! BBAALLAANNCCIINNGG TTHHEE CCOOLLOORR Color balance may be corrected by tweaking with the color adjustments (NOT the color drive, on-screen control, or low level controls). They are usually marked White Balance and almost always come in only Red and Blue. If you don't have white balance, you can go ahead and use the color drive, but I don't advise it. FFIINNAALL CCOOMMMMEENNTTSS Make sure you've put everything back in place correctly. If you plan to be moving the monitor around a lot, and you put in an IC socket, you might want to scrap the IC socket and directly solder the IC. Don't crank up the brightness too much; you risk CRT burn-in. Of course, this is true for any monitor. If your lowest colors (such as 111) look black, don't worry. Most ST monitors I've seen also can't show the lowest colors well. Bill White 71451,755 AAPPPPEENNDDIIXX 11:: TTOOOOLLSS RREEQQUUIIRREEDD You _m_u_s_t have the following: A screwdriver to fit the screws on the monitor Low-powered (electronics) soldering iron with a pointed tip Rosin core solder, as thin as you can get it. Solid wire, about 22 gauge or smaller IC socket, the number of pins depends on what you need (see above) Wire clippers A voltmeter and an ammeter OR a digital multimeter (DMM) A continuity tester OR an ohmmeter OR a digital multimeter (DMM) An Atari ST A monitor cable to connect the ST with the modified monitor You _s_h_o_u_l_d have the following: A schematic for the monitor An anti-static wristband or anti-static work mat A well-stocked parts box A resistor color code index guide You may find the following helpful: An oscilloscope (20MHz or so) 3 silicon diodes (to protect the ST from back-voltage) AAPPPPEENNDDIIXX 22:: TTEERRMMSS UUSSEEDD Anode: In this document, the high voltage line that runs to the CRT from the flyback transformer. Chip: An integrated circuit. Color: 1. One of the three primary colors of light (Red, Green, or Blue). 2. When used with a three digit number, the RGB value that the ST uses (for example, 347 means R=3, G=4, 7=B), set using the Control Panel. CRT: Cathode Ray Tube Flyback transformer: The transformer that generates the signal to move the CRT beam back to the left-hand side of the screen during Horizontal Sync. Physically, a (usually) box-shaped metal frame with a torus-shaped (ie donut-shaped) coil placed on one side, with the frame going through the center of the torus. Gate: An individual logic element in a logic IC (which see). Horizontal Sync: The signal that tells the monitor to move the electron beam back to the left-hand side. Or, the time during which this occurs. IC: Integrated circuit. Logic IC: A digital IC which is composed of several logic gates (which perform logical operations on the incoming binary data). For example, an "OR" chip contains (usually) 4 "OR" gates which perform the logical OR of their inputs (two each). Logic ICs usually have four gates, except "NOT" and buffer IC's which usually have six. Logic ICs often have 14 pins. Op-amp: An Operational Amplifier; a linear IC which gives an output linearly proportional to the input (as opposed to a transistor, which gives an output logarithmically proportional to the input) Pin: On an IC, one of the external leads. On a connector, one of the prongs or individual sockets that connects to a wire. Tweak: One of the three methods of adjustment. TTwweeaakk means to adjust carefully and slowly until the optimum result is present, possibly while monitoring the signal with a voltmeter or oscilloscope. The other two types of adjustment are ttwwiiddddllee, which means to adjust with less care until the results simply look best, and ffrroobb, which means to adjust for no apparent reason. Vertical Sync: The signal that tells the monitor to move the electron beam back to the top. Or, the time during which this occurs. Also called FIELD SYNC. AAPPPPEENNDDIIXX 33:: IIBBMM 88--PPIINN CCOONNNNEECCTTOORR +-------+ | 1 5 | | 2 6 | | 3 7 | | 4 8 | +-------+ (viewed from back of monitor) 1: Intensity 2: R (Red) 3: G (Green) 4: B (Blue) 5: GND (ground) 6: GND (ground) 7: Horizontal Sync 8: Vertical Sync Note that these are not necessarily the pin-outs to YOUR monitor; they just happened to be fairly common. AAPPPPEENNDDIIXX 44:: PPIICCTTUURREESS The pictures are included for your benefit. They are in medium res (I don't have high res), but in black and white so high-res users can load them with Degas or use a program to change graphics formats. They are in Degas uncompressed mode (PI2). They are as follows: 1: The three scenarios described above in TRACING THE CIRCUIT. 2: The new connections made in TRACING THE CIRCUIT. 3: The old and new connections for TAKING CARE OF THE INTENSITY PIN. 4: The piggyback board for INTENSITY SIGNAL CORRECTION. AAPPPPEENNDDIIXX 55:: HHOOWW TTOO CCOONNTTAACCTT MMEE General questions or errata may be left in the ATARI16 forum message area on CompuServe. Specific questions should be sent through E-Mail to me on CompuServe; my User ID is 71451,755. I will soon be getting onto BitNet, but that may take awhile. If all else fails, you can write to me (send me a self-addressed, stamped envelope): Bill White 7774 Country Club Rd Athens, OH 45701 (614)-592-1619 AAPPPPEENNDDIIXX 66:: CCOOMMIINNGG UUPP Soon I plan to modify an inexpensive high-res monochrome monitor chassis to work with the monochrome mode. The problem is that the Atari 16 bit machines use a 70Hz scan rate. I've heard that this is for higher quality. Actually, the human eye can't tell the difference. I think the real reason is that everybody's favorite person Jack T. didn't want third-party monitors being used (after all, an analog RGB monitor is hard enough to find from third-party even now, but monochrome monitors are everywhere). Anyway, when I finish modifying mine I'll try a couple of others, and when I get it down I'll send in the info. I know it can't be that hard. And I've seen NEW high-res monochrome monitor chassis for $50 or less in surplus magazines. Also coming up sometime Real Soon Now, I hope to build a physical Ram Disk (as in it plugs onto your computer like a disk drive but is fast like a ramdisk, and it holds its memory even when you power it down). The advantage is that it's fast, takes up no ST memory, AND unlike a normal ramdisk, if you lose your power, it'll still be in there. I'm undecided as to what port to use. Any suggestions? Bill White 71451,755 ******************************************************************** Deze diskette is samengesteld door de Stichting ST, Postbus 11129, 2301 RH Leiden. Onze bibliotheek van public domain programma's omvat op dit moment (zomer 1988) al zo'n drie honderd disks. Daarop vindt u programma's op elk gebied, van tekstverwerker en database tot de leukste spelletjes, de fraaiste tekenprogramma's en de handigste utilities. Ook bevat onze bibliotheek een speciale afdeling voor public domain disks met Macintosh software, die te gebruiken zijn onder de ALADIN emulator. Deze MAC-PD serie bevat tot nu toe ongeveer vijfendertig disks. ******************************************************************** U vindt in het twee maandelijks tijdschrift "ST" (Onafhankelijk tijd- schrift van en voor gebruikers van Atari ST computers) een overzicht en een bespreking van de inhoud van de nieuwe public-domain diskettes. Dit tijdschrift bevat tevens een bestelkaart zodat U vlot over de software kunt beschikken. De Stichting ST geeft ook een speciale PD catalogus disk uit. ************** Deze public domain disk is geproduceerd en gedistribueerd door: Stichting ST afd. Software Bakkersteeg 9A 2311 RH LEIDEN ************** Ondanks onze controle komt het af en toe voor dat een diskje niet goed is gecopieerd.Mocht U dit overkomen, aarzel dan niet en stuur de defecte disk aan ons terug. U krijgt dan direct een vervangende disk toegestuurd. ************************************************************************ Teneinde het voor ons mogelijk te maken om productie fouten op te sporen en vervolgens in de toekomst te vermijden, zijn alle disks, geproduceerd door de Stichting ST, voorzien van een groen productie nummer. ************************************************************************