Sometimes electronic things stop working. Strangely enough, a lot of
people don't know what to do when this happens and they throw
something out than can be easily fixed. It's true that a lot of
products today are designed to be disposable, but armed with a little
knowledge you just may be able to salvage something that would
otherwise be consigned to the scrap heap.

In this article I'll cover some basic techniques for troubleshooting
common problems with small electronic items, hopefully without
electrocuting yourself in the process.

A Word About Safety

Speaking of electrocuting oneself, before we go any further we should
have a little talk about safety. Unlike in the days of vacuum
tubes¹,
most electronic equipment today operates on low voltages which are
relatively safe. Despite that, always make sure equipment is unpowered
when you are working on it! There is still be the possibility of large
current flows which could cause fire or burns, or more likely, you
will cause damage to the equipment itself when you drop a screw inside
or cause a short circuit as you poke the innards with a metal
tool. This means not just turning off the power switch but unplugging
all power cords and other cords and removing batteries. If the device
is solar powered, only work on it at night².

An exception to the statement about high voltages is anything that
has a Cathode Ray Tube (CRT) such as televisions and computer
monitors. These work with voltages that can easily exceed 20,000
volts, and to make matters worse, the voltage can still be present
even when the device is unplugged. Unless you are familiar with how to
discharge a CRT you should stay away from opening a TV or computer
monitor.

Still talking high voltage, modern electronic circuitry such as that
in computers, radios, and calculators, can be sensitive to the high
voltages that are generated by static electricity. The static charge
you build up walking across a carpet can easily damage the components
inside this equipment if you should touch them. A common example would
be installing or removing a circuit board in a computer. There are
conductive wrist straps and mats that you can buy to protect equipment
from static voltages, but if you want to avoid the expense, you will
generally be safe if you first touch the metallic case of the
equipment (e.g. computer) to before touching any of the internal
components.

Some equipment contains more dangerous stuff: lasers, microwave ovens,
radio transmitters, etc. Most smoke detectors contain a small piece of
radioactive material. You should just stay clear of these and leave
them to an expert.

Are you one of those people that always seem to have parts left over
after taking something apart and putting it back together? While
almost everything has the standard "no user serviceable parts inside"
label, there are some items that just aren't designed to be
repaired. Some may be permanently sealed shut, or may contain many
tiny parts that are virtually impossible to get back together. Some
may require special tools like a star shaped screwdriver to open. If in
doubt, don't open it up unless you know the item will be thrown apart
anyway and you have nothing to lose.

Know Your Limitations

I'm talking here mainly about small electronic devices such as radios,
small appliances, toys, telephones, etc. Larger items like washing
machines and refrigerators have electronics but obviously have a
mechanical aspect to them as well. Use common sense in deciding if you
are capable of tackling these items. For a small inexpensive item you
have little to lose by trying to fix it, but think twice before
working on something valuable or difficult to replace. You probably
wouldn't take apart a gold pocket watch or car engine just for fun, so
think twice about opening up that new DVD player or camcorder just to
see what makes it tick.

Debugging Techniques

Before we talk about specific types of devices, there are some general
rules that apply to diagnosing any repair. Be logical. The device must
have broken for a reason. When did it last work? Did something change
about the way you use it? Were there any clues when it failed (e.g. a
funny smell, smoke, a thunderstorm?). Is it completely dead or just
malfunctioning in some way. Generally a completely dead device
indicates a simpler problem than one that malfunctions in some more
subtle way.

Checking The Obvious

Surprisingly often the problem may be something so obvious that you
overlook it. Is it plugged in? Are you sure it is getting power? (plug
something else into the same outlet to make sure). If connected with a
power bar, is the power bar plugged in, turned on, and known to be
working? Can you swap the line cord with one that is known to be good?

More complex devices with many switches, like clock radios, may appear
to be non-functional because the switch settings were changed.

Many devices have more than one power switch; computers are notorious
for this. There may be one power switch on the front but there is
likely at least one more on the back that may be turned off.

With battery operated items check or replace the batteries. Don't
assume that the replacement batteries are good -- test them. Make sure
the batteries are inserted correctly. Are the batteries loose?
Sometimes batteries fail to make contact, and this can be corrected by
slightly bending the clips that contact the battery. Make sure the
batteries are of the correct type, this can be the case for items like
watches and calculators where there are many similar types.

Some items, such as hair driers, have switches for the line voltage
setting. Make sure it was not inadvertently set to the wrong
position.

Many devices today use AC adaptors -- those little square power cubes
that steal all the outlets from your power bar. The AC adaptor could
be bad or have been replaced with the wrong one. Adaptors come in many
different voltages and polarities and are not interchangeable even if
the connector appears to fit. If it fails or has been lost you can buy
a "universal" adaptor as a replacement.

Look At All Those Bits!

Once you've eliminated the obvious, it's time to open up the device
and look inside. A visual inspection is really all you need to do.
Look for loose wires or parts, burned components, or leaky batteries.
Look for burned fuses inside the device.

Some devices, such as cordless phones, may contain rechargeable
batteries. These have a finite lifetime and eventually need to be
replaced. Usually they will slowly fail to hold a charge over a period
of time rather than simply failing, but sudden failure is
possible. Check with your local authorities for instructions on the
disposal of old rechargeable batteries as they can contain toxic
chemicals that are harmful to the environment.

Tools Of the Trade

Digital multimeters can be bought inexpensively at most hardware or
building supply stores. These will let you measure voltages as well as
checking continuity of wires and fuses. Use caution when measuring
voltages. Less expensive is a neon test lamp that can quickly
determine if power outlets are working. To fix broken wires, you will
need a soldering iron. For electronic devices use a low wattage
soldering pencil type, not a soldering gun as this will overheat and
damage sensitive components. Do not use the acid core solder intended
for plumbing, the acid will slowly eat away at the wires.

Replacement electronic parts can be purchased at stores such as Radio
Shack. These can be expensive, however. If you do a lot of repairs you
should try to build up a "junk box" of spare parts kept from devices that
couldn't be repaired or discarded by other people.

Computers

You are not realistically going to be able to unsolder that Pentium
chip from you computer and put another one in. The surface mount
technology used in most computer circuitry is manufactured using
robotics. You can however do some maintenance that may avoid problems
before they occur. Computers tend to accumulate a lot of dust inside
which can make the fans less efficient at cooling. Opening up your
computer and cleaning it out is recommended every few months,
depending on how dusty the conditions are. A vacuum cleaner is not
recommended -- it is too powerful and can generate static
electricity. The experts use cans of compressed air to blow the dust
out, unfortunately these cans of air are quite expensive. In a pinch
you can just pull the largest of the dust balls out by hand. Make sure
the fans are clear of dust and running smoothly. Speaking of fans, the
fan mounted on the CPU chip often fails after a couple of years. If
you hear strange grinding sounds from inside the computer, the
bearings in the fan have likely worn out and are about to fail. You
should replace the fan as soon as possible, otherwise the expensive
CPU chip will likely fail due to overheating.

Keyboards also tend to collect dirt and dust. If you don't have a can
of compressed air to blow it out, you can carefully pry the keys off
of most keyboards and clean them with Q-Tips. Make sure you draw a
diagram of the keyboard locations before you remove all the keys so
you can easily replace them.

Telephones

With cordless and cell phones the most likely problem is with
rechargeable batteries. Wired phones, unless it is as simple as a
faulty cord, are difficult to repair. In regions such as North America
where phone deregulation means that the telephone is not supplied by
the phone company, many telephones are now manufactured based on
achieving the lowest possible cost and they are essentially
disposable.

Note that the voltages used for wired telephones is high enough (48V)
that it can be considered dangerous, and an even higher alternating
current voltage is used for ringing which will definitely give you a
nasty shock if you are touching the wires.

Small Appliances

Small Appliances such as blow driers, etc. have little electronics and
simple broken wires or faulty switches are often the cause. Some
devices have internal fuses, possibly soldered in, which can fail if
the devices overheat.

Audio Equipment

A common problem with older or lower cost audio equipment such as
stereos, portable radios, and CD players is that the controls for
volume, tone, or other settings become noisy. Often this can be
fixed using contact cleaner.

When All Else Fails

If all else fails and you can't fix it, you have a good excuse for
buying a shiny new gadget. I have a microwave oven that is almost 20
years old that set me back almost $1,000 when new and is still working
perfectly. I'm getting a little tired of the simulated wood grain
finish and am eagerly awaiting the day it fails so I can buy a new
one.