(From: Fred Noble) Fred_Noble@msn.com)). Monitors are very susceptible to electromagnetic fields. If any of the following is "yes" it may point to an 'electrical' cause of the Monitor problem. * Do you have a ceiling fan in the same room turned on? * Do you have a wireless telephone in the room? * Do you get similar effects on your TV? * Are you near a large transformer, substation, or high voltage overhead wires? * Is your computer located close to the meter on the other side of the wall? * Do you have speakers next to the monitor? Are they shielded? * Do you have a phone or other device with a magnet in it near the monitor? * Is the cabling routed too near a printer cable? * Do you have a surge/power strip or UPS near your monitor? Reposition the monitor or move it to a different location. Also make sure that you are turning the monitor on first and then the system to ensure that the video card is properly recognizing the monitor. Check cable connections (make sure no other cables are crossing the monitor cable. If you have an extension on the monitor output cable then remove it as well. Try swapping out the monitor to verify if it really is the monitor or take your monitor to another system and see how it responds there. If you are plugging the monitor into a surge strip, remove it from there and plug the monitor directly in the wall outlet. Discussion: There might be an ambient RFI/EMI electrical or magnetic field present around your computer location. Some of the electrical field or the conducted RFI/EMI electrical "noise" causes are considered here. Rough summary of excessive magnetic & electric fields: * Cause: Electrical wiring errors. Electrical wiring errors such as inappropriate or non-NEC code neutral to ground bonds in the facility (not at the common bus in the mains), and other non-NEC Code wiring that results in the HOT wire fields not being OFFSET by the neutral wire fields. Incorrect wiring will be aggravated (and will be noticed first) on a circuit where there is an Air Conditioner, copier, laser printer. Correction: This is an electrical problem that has resulted in a *net current* flowing in the facility and is also a shock hazard. Don't use devices that dump current onto the neutral line, and have an electrician correct the wiring to NEC code. * Cause: Magnetic flux linkages. It is normal for transformers to use magnetic flux linkages (to couple primary to the secondary). Correction: Keep transformer based equipment away from sensitive equipment. There are other corrective measures here that can be discussed on the design level and on the application level. If the transformer is used to power a "noisy" load (high harmonics) perhaps a good harmonic filter can be used between the transformer and the load (example a good UL 1283 noise filter or Surge suppressor with UL 1283 filter). * Cause: Motors also use magnetic flux linkages in normal usage. Correction: Keep large, active, motors away from sensitive equipment (and try to keep them on a different circuit if possible). The use of a good harmonic filter on that circuit will help reduce the harmonics (for example, a good surge suppressor with a UL 1283 RFI/EMI filter, or a Line Conditioner). * Cause: UPSs, especially when on inverter (during brownout or blackout) create magnetic & electric fields. Correction: Keep them away from sensitive loads, and advise manufacturer of problems encountered with the UPS. The UPS may have a faulty inverter circuit or part, or may be in need of a re-design.
If there is a general loss of picture but there is light on the screen if the brightness is turned all the way up, then this is a video input, video amplifier, RGB driver, or power supply problem. If it recovers after being off for a while, then you need to try a cold spray in the video/controller to identify the component that is failing. Take appropriate safety precautions while working in there! If it stays broken, then most likely some component in the video circuitry, controller, or its power supply as failed. There is a good chance that it is a bad colder connection - the trick is to locate it!
These fall into the category of wavey lines, contour lines, or light and dark bands even in areas of constant brightness. These may be almost as fine as the dot pitch on the CRT or 1 or 2 cm or larger and changing across the screen. If they are more or less fixed on the screen and stable, then they are not likely to be outside interference or internal power supply problems. (However, if the patterns are locked to the image, then there could be a problem with the video board.) One cause of these lines is moire (interference patterns) between the raster and the dot structure of the CRT. Ironically, the better the focus on the tube, the worse this is likely to be. Trinitrons, which do not have a vertical dot structure should be immune to interference of this sort from the raster lines (but not from the horizontal pixel structure). You can test for moire by slowly adjusting the vertical size. If it is moire, you should see the pattern change in location and spatial frequency as slight changes are made to size. Changes to vertical position will move the patterns without altering their structure - but they will not remain locked to the moving image. If they are due to the raster line structure - your focus is too good - the patterns will remain essentially fixed in position on the face of the CRT for horizontal size and position adjustments - the patterns will remain fixed under the changing image. How to eliminate it? If moire is your problem, then there may be no easy answer. For a given resolution and size, it will either be a problem or not. You can try changing size and resolution - moire is a function of geometry. Ironically, I have a monitor which is nicer in this respect at 1024x768 interlaced than at 800x600 non-interlaced. Some monitors have a 'Moire Reduction Mode' switch, control, or mode. This may or may not be of help. One way to do this is - you guessed it - is to reduce the sharpness of the beam spot and make the picture fuzzier! Another approach adds a high frequency dither to the beam spot position which may result in a headache! You might find these cures to be worse than the disease. Another cause of similar problems is bad video cable termination creating reflections and ghosting which under certain conditions can be so severe as to mimic Moire effects. This is unlikely to occur in all colors with a VGA display since the termination is internal to the monitor and individual resistors are used for each color (RGB). I think it is ironic that some people will end up returning otherwise superb monitors because of moire - when in many cases this is an indication of most excellent focus - something many people strive for! You can always get rid of it - the converse is not necessarily true!
(From: Bob Myers (firstname.lastname@example.org)). The density of the holes in the shadow mask set an upper limit on the resolution supported by that monitor. Lower resolutions work just fine; there is no need to have the logical pixels in the image line up with the physical holes in the mask (nor is there any mechanism to make this happen), and so you can think of this as the "larger pixels" of the lower-res image simply covering more than one hole or slot in the mask. As the effective size of the pixels in the image approach the spacing of the mask holes, individual pixels are no longer guaranteed to cover enough phosphor dots on the screen to ensure that they are constant color or constant luminance, but an image will still be displayed which ON AVERAGE (over a reasonably large area) looks OK. Actually, the specified "top end" format ("resolution") for most monitors usually is at or slightly beyond this point - the effective pixel size is somewhat UNDER the dot pitch.
"I've got a desktop computer with a VGA monitor above it. To the left of it (a few inches away), I have a VCR with a Commodore composite monitor above it (1084 model). I don't have Cable TV or anything special, just a simple antenna connected to the VCR to pick up the two local TV stations. The reception is pretty good with the computer off, but the problem arises when I turn the computer on. The VCR is already plugged into a different outlet than the computer. Since I am into video production, I need this setup as it is laid out (close together). So, how can I shield the VCR from the interference from the computer? Can I do something with the antenna to make the signal stronger, or can I place some kind of material between the VCR and computer?" Your PC is a serious RF emitter. Areas of leakage include the case as well as the possibly the monitor and cable. Turn off the monitor and/or unplug the video cable to see if it is the latter. You PC's case may not have adequate shielding. Better cases have grounding fingers and proper RF shielding throughout - that is one reason they are more expensive. This may be an option. The VCR may be picking up the interference internally or via its antenna. There may be some options but you first need to determine where the interference is coming from and where it is being picked up.
"I have an old vga monitor that I screwed up. I plugged it into the vga card upside down. Now I know that seems impossible, but believe me, it isn't. Now the vertical is fine, but the horizontal is all screwy. (is that a word? screwy?) It's about 8" wide and can't be adjusted to normal size. The result is a very, um, interesting image. Is it possible that I did some minor damage like blowing a cap, diode, or horizontal transistor?" I'll give you 100:1 odds that you bent the H sync pin and it is now bent over and not inserted in its hole. Remove the connector, and examine the pins - if this is the case, take a pair of needlenose pliers and **very carefully** straighten it out. If it was pushed in, grab hold and pull it out to the same length of the other pins and if necessary, put a drop of adhesive at its base to prevent it from being pushed in again. If it breaks off or is unreachable, you will need to replace the connector (unless the shell comes apart which is usually impossible or at least not easy on newer monitors).
These could be a problem with the video source - bad pixels in the video card's frame buffer or bad spots on a camcorder's CCD, for example. Or, they could be dirt or dead phosphor areas in the CRT. Except for problems with the on-screen character generator, it is unlikely that the monitor's circuitry would be generating isolated spots. You can easily distinguish between video problems and CRT problems - missing pixels due to the video source will move on the screen as you change raster position. CRT defects will remain stationary relative to the screen and will generally be much more sharply delineated as well. There is a specification for the number and size of acceptable CRT blemishes so you may have to whine a bit to convince the vendor to provide a replacement monitor under warranty.
Modern monitors are usually designed to permit software to control various levels of power saving ('green') features from blanking the screen to totally shutting down. Problems can occur if the software to control these features is not compatible with the monitor or not set up correctly or is attempting to control a monitor that lacks power saving modes or is defective or incompatible. A monitor that behaves normally under most conditions but emits a high pitched whine when the computer attempts to direct it into power saving mode is probably not understanding the commands or does not have the appropriate power saving features. It probably behaves about the same as if there is no video signal - which indeed may be the case as far as it is concerned. Many monitors not receiving proper sync signals are perfectly happy driving everyone in the office insane with that high pitched whine. Others will blow up eventually. Recommendation: don't use power saving until you have the proper software. Of course, your monitor could be defective and your current software is actually fine. Check your user manuals to determine compatibility and setup parameters. Also see the sections: "Monitor life, energy conservation, and laziness" and "Implications of power saving modes".
Problem: I have a 17" monitor that has an image that EVER SO SLIGHTLY drifts to the left (and stops) after a long day's work (heat, I suppose). Also, the vertical height shrinks a little bit. Is this at all normal/acceptable? How much is 'ever so slightly'? There are a fair number of components whose values could alter the position/size of a monitor image. I do not find it at all surprising that there should be a small shift due to heat. It really depends on many factors including the basic design, quality of components, ventilation/cooling, etc. Of course, it is possible to have a monitor that has a component that is worse with respect to temperature. Could also be related to line voltage depending on the regulation of your monitor's power supplies. In general, my feeling is that if it is not objectionable (a 1/2" shift would be objectionable) AND it's severity is not changing with time, you can ignore it. Many monitors do this. TVs do this but you are not aware of it since they are already 5-10% overscanned for just this reason, as well as compensating for component aging and line voltage fluctuations. A can of cold spray or a heat gun will be useful to track down the bad component but it could be a frustrating search.
It could be the monitor's components have drifted and are now marginal at your one or more of your scan rates. However, first check with an oscilloscope if possible to confirm that your horizontal and vertical timing are indeed as expected. Some video cards modify horizontal and vertical frequency as part of their software size adjustment in their Setup program. For example, with ATI cards, even though the general resolution option in the DOS Install program may be 800x600 at 75 Hz, adjusting the horizontal size can actually vary the horizontal frequency over a greater than 10% range. A similar variation is possible with the vertical rate. Does just the picture go away or does power die to the monitor? If you can see the neck of the CRT, the filaments glow orange when it is operating. Does this glow disappear indicating that the deflection/HV is shutting down? There could be a number of possibilities - no way of knowing if it will be easy or inexpensive to repair without testing. It could be power supply, HV supply, X-ray protection, etc.
This is almost certainly a software problem. First, try moving the monitor away from the PC as far as the cable will stretch. If it still occurs, then it is probably not the monitor. Could have to do with power saving (just a guess) or some other incompatibility. Nothing the PC does should affect the monitor in any way once the refresh rate is set.
Do you actually mean buzz - low frequency as in 50 - 120 Hz? Or, do you really mean high pitched whine. If the latter, see the section: "High pitched whine or squeal from monitor with no other symptoms". The size of the monitor is not a strong indicator of the severity of the problem but there will be some relationship as the power levels are higher for larger sets. * If it is from inside the monitor - make sure it is not your multimedia speakers or sound card picking up interference - it is in the deflection (probably vertical) or power supply. Either of these can vary in severity with picture content due to the differing current requirements based on brightness. It could be a power supply transformer, deflection yoke, or other magnetic component. Even ferrite beads have been caught buzzing when no one was looking :-). Any of these parts could vibrate if not anchored securely or as they loosen up with age. Some hot-melt glue, RTV silicone, or even a strategically wedged toothpick may help. A new part may or may not quiet it down - the replacement could be worse! For yoke noise, see the section: "Reducing/eliminating yoke noise". * There is a slight possibility that the AC power in your home or office has some harmonic content - the waveform is not sinusoidal. This might be the case if you try to run on the same circuit as an active dimmer or something else with thyristor control. Proximity to heavy industry could also cause this. Relocating the offending device to another branch circuit may help. You could also try a line conditioner (not just surge suppressor) which includes filtering. Else, petition to have that paper manufacturer move out of the neighborhood :-). * Sometimes, it is simply a design or manufacturing defect and the only alternative is a replacement - possibly a different brand. It may be more difficult to quiet down a buzz than a high pitched whine. * Some monitorss are simply poorly designed. You cannot infer the severity of this annoyance from any specifications available to the consumer. It is strictly a design (e.g. cost) issue. The size of the monitor is not a strong indicator of the severity of the problem but there will be some relationship as the power levels are higher for larger units. The best you can do is audition various monitors very carefully to find one that you are satisfied with. * One those rare monitors that have a cooling fan, its bearings may be worn or in need of cleaning and lubrication, or a blade may be hitting something.
Sometimes this is continuous. In other cases, it comes and goes almost as though there is an intelligence at work attempting to drive you crazy. All the more so since a technician may not even be able to hear what you are complaining about if their hearing is not as sharp at high frequencies as yours. Even high resolution computer monitors running at high horizontal scan rates (beyond human hearing) can have these problems due to the switching power supplies as well as subharmonics of the horizontal scan rate exciting mechanical resonances in the magnetic components. If it is a new monitor and think the sounds will drive you insane, returning it for a refund or replacement may be best alternative. However, you may get used to it in time. Note: if the whine only occurs when the monitor is unplugged from the computer or the computer is turned off, this is probably normal. Without valid sync signals the monitor defaults to a horizontal rate which is within the audible range (less than 20 KHz). Any vibrating components will be readily heard. It is usually not a sign of impending failure. In most cases, this sound, while annoying, does not indicate an impending failure (at least not to the monitor - perhaps to your mental health) or signify anything about the expected reliability of the set though this is not always the case. Intermittent or poor connections in the deflection or power supply subsystems can also result in similar sounds. However, it is more likely that some part is just vibrating in response to a high frequency electric current. There are several parts inside the monitor that can potentially make this noise - the horizontal flyback transformer and to a lesser extent, the deflection yoke and associated geometry correction coils would be my first candidates. In addition, transformers or chokes in the switching power supply if this is distinct from the horizontal deflection circuitry. You have several options before resorting to a 12 pound hammer: * As much as you would like to dunk the monitor in sound deadening insulation, this should be avoided as it will interfere with with proper cooling. However, the interior of the computer desk/cabinet can be lined with a non-flammable sound absorbing material, perhaps acoustic ceiling tiles. Hopefully, not a lot of sound energy is coming from the front of the monitor. * Move the monitor out of a corner if that is where it is located - the corner will focus sound energy into the room. * Anything soft like carpeting, drapes, etc. will do a good job of absorbing sound energy in this band. Here is your justification for purchasing those antique Persian rugs you always wanted for your computer room :-). If you are desperate and want to check the inside of the monitor: * Using appropriate safety precautions, you can try prodding the various suspect parts (flyback, deflection yoke, other transformers, ferrite beads) with an insulated tool such as a dry wooden stick. Listen through a cardboard tube to try to localizing the source. If the sounds changes, you know what part to go after. Sometimes a replacement flyback will cure the problem unless it is a design flaw. You do not want to replace the yoke as convergence and other adjustments would need to be performed. Other transformers can be replaced. * Sometimes, tightening some mounting screws or wedging a toothpick between the core and the mounting or coils will help. Coating the offending part with sealer suitable for electronic equipment may quiet it down but too much may lead to overheating. A dab of hot-melt glue or RTV silicone may help. Even replacement is no guarantee as the new part may be worse. For yoke noise, see the section: "Reducing/eliminating yoke noise". * A few monitors have internal cooling fans. The whine may be due to worn or dry bearings. If this is the case, the fan must be serviced as it is not likely doing it job and damage due to excessive temperatures may eventually be the result. Note that the pitch of the whine - the frequency - may not even be audible to a technician assigned to address your complaint. The cutoff frequency for our hearing drops as we get older. Someone over 40 (men more so than women), you may not be able to hear the whine at all (at least you can look forward to silence in the future!). So, even sending the monitor back for repair may be hopeless if the technician cannot hear what you are complaining about and you are not there to insist they get a second opinion!
(From: Bob Myers (email@example.com)). In standby, the monitor is not being supplied with horizontal sync, and so the horizontal deflection circuits are free-running. (If they're still powered up in a given monitor design when in standby mode, that is; there are no standards governing what actually gets shut down in the various power-saving states.) It's likely that in this case, the horizontal is free-running at a frequency which is audible, and you're hearing a whine from a vibrating transformer core (for example, the flyback). This will NOT have anything to do with the timing used when the monitor is on and running normally, so it's no surprise that changing the refresh rate didn't affect this. You can either have a technician try to track down the offending component and try to keep it from making the noise (usually by adding some "goop" to prevent or at least reduce the audible effects of the vibration), or you might try (if your system permits it) using one of the other power-management states instead of standby. Removing BOTH the horizontal and vertical sync signals places the monitor in the "off" condition (I'm assuming compliance to the VESA DPMS standard throughout this discussion), in which just about everything should be shut down. However, since this will remove the heater supply from the CRT as well, it WILL take longer to recover from the off state.
(From: Terry DeWick (firstname.lastname@example.org)). Carefully look under vertical core next to plastic liner, on top and bottom is a plate called the astigmatism shunt, it has come loose. Work RTV, epoxy, or service cement onto it to glue it down and noise should quit. (From: TVman (email@example.com)). I have fixed a total of 27 of these sets with noisy yokes by removing the yokes and using motor armature spray sealant. If you carefully mark the EXACT position of everything (yoke, purity magnets), and slide the yoke off the CRT, then once the yoke has been sealed with motor armature spray sealant and has dried thoroughly, put the yoke back EXACTLY where it was, there should be no problems. The only thing I have had to do was set the purity on one set, but it was off a little to begin with.
Was the set plugged in when the leak started? Any piece of equipment with remote power-on capability has some portions live at all times when plugged in and so there may have been damage due to short circuits etc. Substantial damage could have already been done. Otherwise, you may just need to give it more time to dry out. I have had devices with keypads getting wet that required more than a week but then were fine. There are all kinds of places for water to be trapped and take a long time to evaporate. If the monitor got wet while unplugged or it has a mechanical (hard) on/off switch, then give it a lot of time to dry out completely. Assuming all visible water is drained, a week represents a minimum safe time to wait. Don't rush it. Generally, some moisture will not do any permanent damage unless the set was on in which case you will simply have to troubleshoot it the old-fashioned way - one problem at a time.
If your work area is maintained like that of Nedrie in the movie "Jurassic Park, you might not even notice if one your monitors fell off the table! This is no way to treat a monitor. However, mishaps do happen. Assuming it survived mostly intact - the CRT didn't implode, you could still have a variety of problems. Immediately unplug the monitor! If you take it in for service, the estimate you get may make the national debt look like pocket change in comparison. Attempting to repair anything that has been dropped is a very uncertain challenge - and since time is money for a professional, spending an unknown amount of time on a single repair is very risky. There is no harm is getting an estimate (though many shops charge for just agreeing that what you are holding was once a - say - a monitor, or was it a fishtank?) This doesn't mean you should not tackle it yourself. There may be nothing wrong or very minor problems that can easily be remedied. The following are likely possibilities: 1. Cracked circuit boards. These can be repaired since monitors usually have fairly wide open single or two sided boards. 2. Broken circuit components. These will need to be replaced. 3. Broken solder connections particularly to large heavy components on single sided boards. Reflow the solder. If the trace is cracked or lifted, repair as in (1). 4. Broken mounting brackets. These are usually made of cheap plastic and often don't survive very well. Be creative. Obtaining an exact replacement is probably not worth the trouble and expense. 5. Components knocked out of line on the CRT envelope or neck - deflection yoke, purity magnets, convergence magnets and coils, geometry correction magnets. These will need to be reattached and/or realigned. Some CRTs use little magnets glued to the funnel portion of the CRT envelope. If any of these have come loose, it could be quite a treat to figure out where they went and in what orientation. 6. Internal damage to the CRT - popped or distorted shadow mask, misaligned electron guns. Unfortunately, you will probably have no way of identifying these since you cannot see inside the CRT. They will not be apparent until all other faults have been remedied and the TV set is completely realigned. At that point, extremely severe purity or convergence problems that do not respond to the normal adjustment procedure would be one indication of internal damage. Give the TV a nice funeral. If you still want to tackle a restoration: As noted, unplug the monitor even if it looks fine. Until you do a thorough internal inspection, there is no telling what may have been knocked out of whack or broken. Electrical parts may be shorting due to a broken circuit board or one that has just popped free. Don't be tempted to apply power even if there are no obvious signs of damage - turning it on may blow something due to a shorting circuit board. Then, inspect the exterior for cracking, chipping, or dents. In addition to identifying cosmetic problems, this will help to locate possible areas to check for internal damage once the covers are removed. Next, remove the cover. Confirm that the main filter capacitors are fully discharged before touching anything. Check for mechanical problems like a bent or deformed brackets, cracked plastic parts, and anything that may have shifted position or jumped from its mountings. Inspect for loose parts or pieces of parts - save them all as some critical magnets, for example, are just glued to the CRT and may have popped off. Carefully straighten any bent metal parts. Replace parts that were knocked loose, glue and possibly reinforce cracked or broken plastic. Plastics, in particular, are troublesome because most glues - even plastic cement - do not work very well. Using a splint (medical term) or sistering (construction term) to reinforce a broken plastic part is often a good idea. Use multiple layers of Duco Cement or clear windshield sealer and screws (sheetmetal or machine screws may be best depending on the thickness and type of plastic). Wood glue and Epoxy do not work well on plastic. Some brands of superglue, PVC pipe cement, or plastic hobby cement may work depending on the type of plastic. Inspect for any broken electronic components - these will need to be replaced. Check for blown fuses - the initial impact may have shorted something momentarily which then blew a fuse. There is always a risk that the initial impact has already fried electronic parts as a result of a momentary short or from broken circuit traces and there will still be problems even after repairing the visible damage and/or replacing the broken components. This is most likely if the monitor was actually on but some modern monitors have circuitry that is energized at all times. (If power is controlled by a tiny tiny pushbutton this is the case.) Examine the circuit boards for any visible breaks or cracks. These will be especially likely at the corners where the stress may have been greatest. If you find **any** cracks, no matter how small in the circuit board, you will need to carefully inspect to determine if any circuit traces run across these cracks. If they do, then there are certainly breaks in the circuitry which will need to be repaired. Circuit boards in consumer equipment are almost never more than two layers so repair is possible but if any substantial number of traces are broken, it will take time and patience. Do not just run over them with solder as this will not last. Use a fine tipped low wattage soldering iron and run #22-26 gauge insulated wires between convenient endpoints - these don't need to be directly on either side of the break. Double check each connection after soldering for correct wiring and that there are no shorts before proceeding to the next. If the circuit board is beyond hope or you do not feel you would be able to repair it in finite time, replacements may be available but their cost is likely to be more than the equipment is worth. Locating a junk unit of the same model to cannibalize for parts may be a more realistic option. Degauss the monitor as any impact may magnetize the CRT. Power cycling may work but a manual degaussing is best. Once all visible damage has been repaired and broken parts have been replaced, power it up and see what happens. Be prepared to pull the plug if there are serious problems (billowing smoke or fireworks would qualify). Perform any purity, convergence, or other realignment as needed. Then proceed to address any remaining problems one at a time.
(From: Dr. Ludwig Steininger (firstname.lastname@example.org)). Often I get defective monitors, which are more than 5 years old, and have been run in offices for 8 to 10 hours/day. So, their case and pcbs usually are very dirty and dusty. What do I do (it's no joke!): After removing the case I carefully put them in a bath (on a flexible layer) and let them have a intensive shower of pure cold water (for 1 to 2 minutes). Additionally, the case is cleaned with soap or a detergent containing liquid (being careful, not to spill to much of it onto the PCBs). After rinsing with fresh clear water, dust and other kinds of dirt are removed and the monitors look new again. Then I allow all drops of water to run off. This can effectively be supported by turning the monitor on another side from time to time (duration: approximately 1 hour). Before turning on AC again, I let the wet monitor dry in ambient air for about 2 days (in the sunshine this can be finished in 1 day only). This procedure has been applied for many monitors. I've never had any bad experiences (it's very important to wait, until the pcbs are really dry!). Considering this experience, I just can't imagine, that it might not be possible, to "save" a TV set or computer monitor, which has been drowned or some liquid has been spilled, and AC has been plugged off ASAP (although I've never had such a case). I think, that in such a case, it's important to have a rapid shower in order to prevent corrosion and deposits. By the way: I know a German company, which uses water from cleaning PCBs of computer hardware for cleaning them after being contaminated by smoke from a fire. So, in case of spillage, one has nothing to loose. Just try to shower your monitor or TV set!Go to [Next] segment
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