Computer ON or OFF?

Computer; Leave it on, or turn it off.

Nothing
can stop
~20
million
volt
lightning
strike.

Nothing can stop a ~20 million volt lightning strike. But having the computer and outlet strip turned off can help. Even when the off button is pushed on newer computers and printers, it is not really "off" as there is power going to the button and a "clock" in ink jet printers.

Ten times as many computers in Georgia were damaged by lightning when left on than when left off. Many were damaged by the phone line into the modem. Unplugging everything will help the most.

The picture on the left is a dead CPU which was left on, and whose fan had too much dust. The fan wasn't completely clogged but caused enough extra heat for "Fatal exceptions" to become permanent. Hardware fatal exceptions can also be caused memory, and the motherboard. They are affected by static, lightning, age, dust, corrosion and miss timing.
The CPU fan can be removed from the heat sink and cleaned, then some "3 in One" oil can be used to lubricate the bushing on the bottom to make it last another year. With the computer unplugged, vacuum with an artist's brush, and clean the power supply fan too.

We've covered lightning and dust, now lets get to the slant of this article.
A good reason for turning your computer off might be something you probably haven't thought about.

What is
an ion?

.....Electrolysis
Everyone has opened an old flashlight and seen the corrosion around the positive (top) terminal. The corrosion is from ions floating in the air. Its trying to take place inside your computer too. It is caused by the attraction of negative (non-metal) ions to a positive voltage.
.
What is an ion? In this context it is the chlorine part of a salt solution suspended in moisture, or a sulfur dioxide compound.

You might say, "I don't have ions floating in the air where my computer is located.
Its a bright sunny day and the sky is bright blue after the rain."

The air pollution before the rain probably had sulfur compounds in it.
A tiny trace of salt is in humid air. Even if you live in dry Arizona, you probably use laundry bleach or are within distance of some chlorine source, like your faucet.

		.Here (moist air) salt is pulled apart by the positive (+) voltage on the computer mother board circuit. The chlorine atom is attracted to + and corrodes the circuit board over an extremely long period of time, perhaps 10 years till a failure. In the meantime, it degrades the dielectric. Neutrally charged dust is also attracted to + (or minus) because it has a different voltage potential. Opposites attract.
	*High* *Voltage*	. . . Monitors have high voltage which attracts dust, any spark from them might ignite nearby papers.. Most monitors dissipate as much heat as a computer, but don't have a cooling fan. At the Atlanta Journal and Constitution, monitors have burst into flame by having newspapers on them. After assisting an appraisal of damage to a rare doll collection at a house fire caused by a printer, I promised myself to remind everyone not to leave anything flammable near your monitor, especially when it is turned on.
	HD	Anything with moving parts wears out eventually. The hard drive, CPU fan and power supply fan have moving parts and will wear out if left on. Every time the head of the hard drive goes over the surface of the drive, the drive looses a tiny bit of its rententivity (the ability of a magnetic medium to hold its strength, to make the ones and zeros). Of course, when not in use, the HD is usually parked in an area where it does not matter. When a HD goes bad, first scandisk finds 1 or 2 bad sectors, then next time 4 or 5 then next time 10 or 12. It should be replaced immediately. Free XXcopy can "clone" everything onto the new HD. Available from www.xxcopy.com (in a new window).
	*Light* *bulbs* *burn* *out* *when* *turned* *on.*	One argument to leave your computer turned on. Yes, there is a surge every time a computer is turned on. That is probably when most serious hardware problems show up. And constant temperature changes can put enough stress on circuit boards to "walk" cards right out of their sockets, if they are not screwed down. Unlike a light bulb though, there are circuits to reduce the surge. A few milliseconds after the power supply is turned on and stabilized, it sends out a "power good" signal to the motherboard. Then the board accepts the power and sends a POR (Power On Reset) signal to every chip that has flip-flops to reset their condition to neutral (or not activated) flopped. When a computer doesn't boot correctly, I think it may have a lot to do with the temperature and the simultaneous POR signal. For instance perhaps it flops 2 circuits as it is supposed to and when it "lets go" the first circuit flips the second one to the wrong state. This would show up as a repeatable but transient problem. Computers might have different symptoms on boot up.
		Many more serious things can happen when a computer is left on, especially unattended. If you have a smoke alarm above your computer and you will be in the area, leave it on for an hour or two. Or put it to "sleep" for three hours. If unattended for four hours or more, absolutely turn it off. If you live near Douglas county Georgia, call Doug to fix your computer and do a security check. At 770-732-6005. Doug knows about electrolysis having won 3rd place overall for a sience project about, "The electrolysis of a salt solution using different kinds of electrodes". This was in the '50's dude.