Monitor Maintenance

Monitors are an important, and widely ignored, component of the PC. Often a vendor will toss whatever monitor he has lying around in with your purchase, regardless of its quality, its compatibility with your system, or your own needs and preferences.

You need to insist on the best monitor you can get for your dollar (and better doesn't necessarily mean bigger). Color monitors rely on color CRTs, which use three electron guns to fire three streams of electrons in a beam that will hit a three-dot or three-stripe pattern on the face (hence the terms dot pitch and stripe pitch). Electromagnets force the electron beams to sweep across the display one line of pixels (picture elements) at a time. At the typical resolution of 1,024 by 768, for instance, each line contains 1,024 pixels, and there are 768 lines which must be drawn each time by the electron guns. The electron guns are one source of fuzzy displays; the larger the screen, the more fuzzy the display at the edges of the screen. Cyber types call this astigmatism, same as what causes me to wear glasses with such thick lens edges. The electrons hit the phosphor compound on the monitor display, causing it to glow. The compound glows for varying periods of time and in varying color patterns, giving you the picture that you see on your monitor. Right now your monitor is showing you a mostly white background with black letter-shaped squiggles. When you get sick of this page and plug in Quake,your monitor will work much harder to show you the beasties and backgrounds of that program.

The color CRT contains three different phosphor compounds: red, green, and blue. Different colors are created by the electrons striking the three compounds in different ways. The three compounds are arranged on the screen in three-dot patterns (the stripes consist of three lines of red, green, and blue). Each three-dot, or three-stripe, pattern is called a pixel. The space between dots of the same color is known as the dot pitch; with stripes, it is called the stripe pitch. Monitors come in three types: those using dots (shadow-mask, flat-square, or dot trio), those using stripes (aperture-grille), and a cross between the two (slot-mask). Sony Trinitrons are aperture-grill CRTs, and NEC CromaClears are slot-masks, along with some Panasonics. Most others, particularly the more affordable models, are shadow-masks. Do you care? Not enough to make one type a necessity. The cyber wonks will argue one type over another, but the rest of us can't tell enough of a difference to make buying one kind over another a sticking point when negotiating for a good deal. (Note: a few users find the horizontal wires used in an aperture-grill CRT both visible and annoying. Check one out before you buy one, as you may be one of the discerning - or picky - few.) You will also hear a lot of static about the dot pitch, or DP, or the stripe pitch. Shadow-mask CRTs measure their size in DP, while aperture-grille CRTs measure theirs in SP. They cannot be directly compared. A rule of thumb is that an SP CRT will have a slightly lower number than a comparable DP CRT; for example, an 0.28mm DP is considered roughly equal to a 0.25mm SP CRT. Don't let the salesman blow smoke up you about this one. A good monitor has a dot pitch of around 0.28mm, but a slightly higher number isn't a reason to quit considering the monitor. Dot pitch is only one consideration.

And what the dickens is "refresh rate?" It is the rate that a monitor redraws the screen (watch a video of a functioning monitor to see the screen refreshing itself; thankfully it doesn't look like that to the naked eye). A refresh rate of 85 Hz is virtually flicker-free to the most discerning eye, but a rate as low as 72 Hz is perfectly acceptable for most of us. (Most TVs have a refresh rate of about 30 Hz; no monitor has a rate below 60 Hz.) And a too-high refresh rate can degrade image quality. You can experiment with different refresh settings; keep your eye just above or to the side of your screen, and lower the refresh rate until any perceptible flicker you can detect out of the corner of your eye is gone. How to change the refresh rate? In most flavors of Windows, right-click the desktop, choose Properties, Settings, and click on the advanced button. Under the Adapter tab, you'll see a list of available refresh rates. Choose the highest one that you can get away with (you may have to experiment). In XP, go through Display Properties and choose Settings, Advanced, Adapter, and List All Modes.

Some people find themselves with flickering monitors that induce migraines; they go in to increase their refresh rate, but their only option is 60 Hz. Not good. What's happened is that Windows has lost track of the monitor's Plug and Play configuration, and is using the 60 Hz default as a safety measure (since a too-high refresh rate can damage the monitor). Fortunately, this is an easy fix: just go back into the Properties, Settings, Advanced menu as listed in the tip above, and choose Monitor. Check the "Automatically detect Plug & Play monitors" box, and reboot. If this doesn't work, you'll need to click the Change button and reinstall the monitor. If this doesn't work, your monitor may not be set to support anything higher than 60 Hz under the current resolution rate; lower the screen resolution and recheck the refresh rates to see if you're offered anything better.