Troubleshooting 101 Electronics:
A BoatU.S. Marine Center expert offers some advice---before it's needed. As
every boat owner knows, or will soon learn, Murphy's Law loves being
on the water. Ironically, it originated at Edwards Air Force base,
far from any lake, river or bay. Captain Edward Murphy, an Air Force
engineer, was trying to figure out why a test he was conducting had
failed and discovered an electrician working on the project had improperly
wired a transducer. Disgusted, Murphy uttered the words, "if there's
a way to do it wrong, he will find it." In more modern times,
Murphy's Law has changed to 'if something can go wrong, it will." When
it happens on a boat, the day can go south real fast if there isn't
a troubleshooter onboard.
Mike
Campbell is an electronics expert at the BoatU.S. Marine Center in
Newport, California. Every day he can be found talking with BoatU.S.
Members and offering
advice, which can be considered "trouble shooting" before something
happens. He has received calls from Members in the Pacific Ocean asking how a
VHF or a GPS can be brought back to life and talked them through a series of
steps which, usually, result in the unit doing what it is supposed to do. Campbell
is well aware of Murphy's Law. In fact, he makes a living because of it.
Troubleshooting
a Fixed Mount VHF
The
modern VHF radio that is attached to a shelf or on the console is good
for up to ten years of substantial use-and even longer if
it is taken care
of. Mike
Campbell says many problems appear shortly after a VHF is purchased because
it is installed incorrectly. "The radio has to be mounted with room in back
of it so that air can circulate," he points out, "and too many
times I've had calls from boaters on their cell phones telling me the
radio they just
bought must be a lemon. That just isn't the case most of the time." Instead,
the VHF has been mounted too close to a wall and the resulting heat
it generates isn't allowed to dissipate. This can lead to a complete
shutdown
of the unit and a possible end to its life. Campbell says it is a common
installation problem when a VHF is placed inside a boat because space
is
always at a premium.
Usually, he will tell a boater with a inoperative radio to shut it down
and, if possible, set it on a table. And usually, the radio is up and
running after being allowed to cool down.
"Another common problem with the fixed mount units is the radio lights up
but doesn't do anything else," Campbell says. "This is when you have
to check and see if there is 12 volts getting to the radio. Batteries will operate
with 12.5 volts most of the time but if it has run down, then the problem isn't
the radio but the fact the battery has to be recharged." But before
you turn on the engine or plug in a charger, take a good look at the
battery itself.
If the contacts are corroded, (and you will see it on the posts) then
the output is going to be less than it should be. A wire brush or even
taking
a knife and
scraping the posts will provide a clean surface. The corrosive marine
environment (and salt water is even worse) is always a suspect when
a battery doesn't
seem to be doing what it should be doing.
A variation
on this problem occurs when the user can receive VHF transmissions
but is unable to transmit. It takes more energy to send a message than
it does to receive one. As a result, check the battery contacts again.
If that
appears
to be in good condition, then its time to trace the coaxial cable
in
search of an open or broken section. This is where the continuity
checker is used.
Troubleshooting
a hand held VHF
The
portable VHF radio uses either a Nicad battery (most common) or a lithium
battery (newer and expensive). The first component to
look
at
when a hand
held VHF isn't working is the battery. "Whether it's a fixed mount or a handheld,
the VHF radio problem is usually found in either the power supply or the antenna," Campbell
observes, "and so the first thing you have to understand is
how the battery that is being used operates." Nicad
batteries are rechargeable but this doesn't mean these power sources
will last forever. Over time and through use, the battery
begins to become
less efficient
and eventually has to be replaced. A common mistake that is made
with charging is not allowing the battery to run down (most will
operate
until it has 5%
of a charge remaining). Nicad batteries have a memory. This means
if it isn't allowed
to run down, the battery will actually become less able to hold
a charge. An example is taking a fully charged battery out on
the trailer
boat,
operating it for one hour, taking it home and plugging it again
for another 12 hours.
This isn't healthy and the battery will actually begin to decompose
internally so
that after a period of doing this, the battery will only have
a life of twenty minutes or so. "The rule of thumb for this kind of battery is one hour of
recharging for every hour of use. But use it for eight hours or so before charging
it again, advises Campbell. "That will increase the life of
the battery tremendously."
Another
little known battery fact for hand held VHF radios is that many are
designed with an ability accept AA batteries of
needed. "They have either a separate
tray or a holder and can be switched over to the kind of battery that is going
to be used," Campbell notes. If you own a VHF, get the
instructions out or contact the manufacturer in the event you
can't locate the
AA battery option.
If this is difficult, a BoatU.S. Marine Center can assist if
the radio was purchased from us. One caveat: if your radio
operates
on a lithium battery,
the AA option
won't work. Instead, there is usually a cigarette lighter adapter
included with the purchase (if not, then it's available as
an option).
If
power isn't the problem, then the radio may have a bad antenna.
You'll know this is the situation if you can only receive
but can't transmit.
If this is
the case, the unit may not be repairable onboard. It may
have to be sent to the manufacturer for a new antenna at which time,
the
cost
to do so
could possibly
outweigh the price of a new model.
One
other note about the antenna. VHF radios operate with line of sight.
A 1-watt unit can reach one mile and the 5-watt
unit
(the
most common)
reaches five miles.
It is important to understand since the earth's surface
curves, and you are operating a VHF either in your hand or with a
fixed mount
unit that
has an
antenna a few
feet above the surface of the water, the place you want
to reach may not be "reachable." This
is where sailboats have an advantage because many mount
their VHF antenna on the top of their mast (of course it also means
they
have to climb the
mast if
there is an antenna problem).
Mike
Campbell has had frantic cell phone calls about hand held VHF's that
were inadvertently dropped overboard. "The news I have to give them usually isn't
good," he says," and 90% of the time, the radio is toast." Still,
in the event it happens to you, he suggests the following:
open the radio, take out the batteries and allow to dry
for 24 hours.
Under no circumstances
should
you try to dry it out and operate after only a few minutes
of coming out of the water.
Hand
Held GPS Troubleshooting
The global positioning system (GPS) uses as few as 8
and as many as 10 of the 24 satellites currently in
geosynchronous orbit
(they move
with
the earth's
rotation) 11,0000 miles above the earth. The older
hand-held GPS units can operate for
8 hours on a set of batteries and the newer ones will
last
as long as 12 hours.
The number one problem is the more the GPS is used
to pull up way points and go to different locations and
pages,
the more
power
it is going
to require and the faster the battery is going to weaken.
As
a result, always
have a
good
supply
of AAA batteries on board when the GPS is going to
used for a long trip. Campbell
recalls a frantic phone call from a new user of a handheld GPS who
was onboard his boat and concerned
the
unit
wasn't completing
its
first step
of acquiring
satellites. When he asked the boater where he was
sitting, there was a long pause. He was inside the cabin up
near the V berth.
Lesson Number
One: GPS
needs a clear
view of the sky (for overhead positions) or a nearness
to windows (for satellites located near the horizon)
in order
to operate.
The patch
antenna can't obtain
the satellite signal through thick fiberglass or
metal. It will acquire satellites through bimini tops.
If
the GPS lands in the water and is quickly fished out, chances are good
it is not going to be operable.
Most
GPS units are
labeled as
'water resistant" but
that doesn't mean they are "water proof." They'll
operate fine in a rainstorm or with spray coming
over the side but an extended
soaking
under water
is probably going to mean the end. Still, Campbell
says he's heard of units being opened up, the batteries
taken out and silica gel
placed inside to
displace the
water while drying for 24 hours before being turned
back on and running with little problem. It's rare
when it happens though.
The
Biggest Problem
Being in the trouble shooting business, Mike Campbell
has just about seen (and heard) it all. And through
these experiences,
he's learned
some valid
advice
to avoid the need for trouble shooting: Getting
electronic units wet should be avoided at all
costs. Interestingly
enough, the
place where
this occurs
most
often isn't out in the middle of the lake or
river. It's at
the dock where a boat owner decided to hose the
boat down after a
day on the
water. That's
when
the fixed mount VHF gets soaked or the handheld
GPS is left under a running hose for five minutes. "The
products that are available today are good quality," he says. "The
problems associated with them can usually be
fixed if the boat owner stays calm and thinks the problem through.
If they can't, there is always a BoatU.S Marine
Center that can lend a hand." Mike Campbell
knows that all too well.
Campbell's
Troubleshooting Tools to have Onboard
A
flat and a Phillips screwdriver
-
Diagonal
cutters
-
Pliers
-
Adjustable
wrench (crescent works fine)
-
A
set of socket wrenches and drives
-
Multi
meter-used to measure voltage and amperage. A good one will measure
12,24,32 and 110 volts.
-
Continuity
Checker-has a test light that will illuminate
of the circuit is
operational.
It consists
of an alligator
clip used
for
a ground and
a probe that
detects where there is
a break or an "open" in
the wiring system.
-
Spare
batteries-keep in a cool place and wrapped
in
plastic
bags.
If possible,
bring
them with you
each time
you go to
the boat. Keep
them in
the refrigerator
at home.
-
Patience.
Don't get wound up. Anger makes
the job twice
as difficult.
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