lives as engineers get so caught up with “stuff” that sometimes it’s hard for
us to keep track of it all.
Don’t fret about this yucky situation; you can rehab corroded contacts.
issue of replacing equipment batteries. A good job for an engineering intern is
to log all equipment that uses batteries, listing the equipment and the type of
battery required. Then, on an annual basis, replace the batteries throughout
your plant. The practice is cheap insurance, and you will avoid discoveries like
the one in Fig. 1.
remote temperature monitor was mounted up on a wall. Unless you were really
looking for it, you’d miss it. There it sat until one day the engineer noticed
it wasn’t working.
wait, don’t throw it away. If you have a little patience and about five minutes,
you can restore the corroded contacts to like-new condition.
toothbrush, some baking soda and a bottle of distilled water. The job will get
a little messy, so lay down a paper towel or two to collect corrosive dust as
you remove the batteries.
Simple tools help you combat the corrosion.
in Fig. 3, use a screwdriver to pry the batteries gently out of the case. (Be
careful to keep caustic crud away from your face, especially your eyes. Goggles
and gloves aren’t a bad idea.)
corner of the paper towel, sprinkle a teaspoon of baking soda. Add a little
distilled water in order to make a paste. You can mix the paste using an old
the battery compartment to get rid of as much of the corrosion flakes as
possible, seen in Fig. 4.
Fig. 3: Use
a screwdriver to remove the batteries carefully.
toothbrush with the paste and gently scrub the battery contacts. Like magic,
the remainder of the corrosion will disappear. You may need to repeat the
process a couple of times until the contacts are clean.
the toothbrush with the distilled water and run the damp toothbrush over the
contacts to remove the remaining baking soda. Wipe with a damp paper towel or
napkin to remove residue. Leave the compartment open and let it dry over night.
day, check to make sure there is no moisture. Write the date on your batteries,
install ’em and power up.
sure every battery-powered (or battery-backed-up) device is listed on your
master battery inventory. Change batteries annually, if not more often. If a
battery isn’t doing its job and AC power fails, the device is not backed up.
This can be devastating to critical systems like transmitters or remote control
Fig. 4: Gently
scrub the battery contacts with the basic soda mixture.
addition to keeping track of battery-powered equipment, your log serves as a
battery inventory. You’ll know just how many batteries you’ll need, and their
type, before you start opening equipment at replacement time.
* * *
planning an equipment purchase, do you gather comments via online searches? Several
engineers have told me they take full advantage of the Internet this way to learn
the “word on the street” (or the Web) before spending money. The strategy is
helpful especially when you are shopping for consumer or semi-pro gear, which tend
to have more of a user base. The comments may surprise you and even save you
from a costly error.
Fig. 5 Use
a small brush or another old toothbrush to remove the remaining paste gently from
the battery compartment.
point are “galvanized” bolts that start rusting almost immediately, and screw
heads that pop off when being driven into wood. You’ll find them sold in
plastic packs at the “big box” stores; they likely are Chinese imports.
better source is McMaster-Carr.
There you can find ANSI- and ASTM- specification hardware. The company also
carries code hardware. Heads won’t snap off these.
there are times when you just “gotta have it … now.” But a little planning
comes in handy. Today’s broadcast engineer really doesn’t have the luxury of not
doing it right the first time.
* * *
Chepko was interested in the Aug. 1 Workbench tip about using conductive concrete to protect
buried radials and keep them from thieves.
it works well, but Milan thought of three possible disadvantages.
the conductivity will be less than that of the soil by itself — probably not a
significant difference, but still reduced.
the strength of the conductive concrete is noted to be less than regular
concrete mix. Again, probably not important in this application; but be aware
that you are giving up something.
Milan guesses that this mix will be more expensive than regular concrete mix;
and he’s right.
he suggests digging a wide trench, perhaps V-shaped, and running the copper
radial or strap along the center of the bottom as usual. Depending on the terrain,
it might be good to “tack” it down every few feet so it remains in place.
it with a few inches of the soil you removed in making the trench. That ensures
that the copper is surrounded by the soil, giving the best conductivity. Spray a
little water on the soil to let it compact better and make the next step
that is all tamped down, pour a layer of regular concrete, covering the soil
and copper wire. When the concrete has set, perhaps overnight, fill the rest of
the trench with the remaining soil as usual.
copper is in full contact with the soil; the concrete forms a firm shield above
it and costs less than the special conductive concrete mix. Further, it is readily
Milan’s suggestion may be a
little more labor-intensive, but the extra work may discourage theft, especially
in the case of copper strap.
works with Veni Vidi Video near Atlanta. He says local television news reports
on copper theft stories several times a week. Even the copper cores of air
conditioning units are falling prey to thieves.
Contribute to Workbench. You’ll
help your fellow engineers, and qualify for SBE recertification credit. Send
Workbench tips to firstname.lastname@example.org. Fax to (603) 472-4944.
Author John Bisset has spent 43 years
in the broadcasting industry, and is still learning. He is SBE Certified, and
is a past recipient of the SBE’s Educator of the Year Award.