instead of a “k”) holds digital bits of information recorded either as
magnetic markings (on a hard disk or floppy disk) or as a dark spot or
indentation (on an optically based CD or DVD). The hard disk drive’s
motor can grind to a halt, or the read/write head can crash into the sur-
face, destroying both the mechanism and a chunk of stored information.
On a CD or DVD, the good news is that the failure of the mechanism doesn’t
mean that discs already recorded won’t work in another drive; the bad news
is that CDs or DVDs can be irreparably damaged with scratches, warps, or
cracks, especially if exposed to extremes of heat or sunlight.
Identifying power adapter problems .................................................
The laptop is plugged into a wall socket. You press the On button but the
lights don’t flash, the screen doesn’t change colors, and the earth doesn’t
move. The power doesn’t be.
To identify the problem, let me break down the electrical system (before it
breaks down by itself). Nearly every laptop uses DC (direct current)voltage,
usually in the range of 5–20 volts; almost nowhere in the world outside a lab-
oratory will that type and level of power come out of a wall outlet. Instead,
when you connect a laptop to wall current, you are using a power cord that
includes a small box that converts AC (alternating current)of 110 volts (in the
United States, Canada, and a few other places around the world) or 220 volts
(the standard AC voltage in most of the rest of the world.)
The electrical connector rectifiesor convertsalternating current to direct cur-
rent (removing one of the cha-chas from the back-and-forth movement of AC
to yield a steady cha) and also transformsthe voltage from 110 or 220 down to
the needs of your machine.
The adapter output can go straight to the motherboard or it can be diverted
to pass through the laptop’s battery to recharge it. (Actually, most laptops
include a bit of electrical circuitry that allow you to use the machine at the
same time as the battery is being recharged.)
Excluding a dead or uncharged battery — which I discuss in a moment —
there are two likely sources of electrical problems.
The adapter may not be getting the AC juice it needs
Is the power outlet live? Check it by plugging in a lamp or a radio to the
same outlet — not the one above or below it — to see if power is present.
(Remember that some outlets are controlled by switches on the wall; Europe
and Asia commonly have switches alongside most outlets.)
Chapter 3: Things That Go Bump in the Night (or Day)..............................................
