Avionics News April 2015 - 32

industry

TIPS TO HELP TAKE THE

"If I had an hour to solve a
problem, I'd spend 55 minutes
thinking about the problem and
five minutes thinking about
solutions." - ALBERT EINSTEIN

TROUBLE
TROUBLESHOOTING
out of

S T O R Y

B Y

roubleshooting is one of those elements of the job that
an avionics technician loves or hates. The simplest
boxes can suffer from chronic complications, while the
most sophisticated installations can be silenced by the simplest
of problems. And of course, there's the ticking in your brain to
remind you that your customer is going to question every minute
you spend wearing your best deerstalker hat.
It's often enough to push even the most levelheaded technician
to the brink of a career change.
To help keep you in the fold, we've gathered a few bits of
tribal knowledge and technical tips to help save your sanity the
next time the techno-gremlins arrive on the ramp.

Start with the simple stuff

Sometimes, seemingly big problems can have simple solutions.
Bob Jacobson, owner of Custom Avionics, said that when he's
faced with intermittent communication problems, he begins his
search with the simple things.
"Hand mics - if they're not being used, unplug them," he said.
"If the plug jiggles a little, they can stick on transmit, introduce
noise or even render the intercom inoperative. Unplug the mic and
some problems just go away."
Jacobson also noted that headset jacks could be a problem. "Pilots think their headset is plugged in correctly and it's not," he said.
"Also, check the volume settings on the headsets and radios; unplug and re-plug all headsets. Some older navigational units have
separate on/off knobs that can get switched off inadvertently.
"Another item on my list of communications troubleshooting
32

avionics news

april

2015

D A L E

S M I T H

tips are simple things like external USB chargers - especially
the dual-port type chargers. Sometimes when you plug them in
the cigarette charger, you can't use the radios. I experienced that
problem myself. My biggest tip would be that before you do anything, make sure everything in the aircraft is put back to its factory settings - on/off, volume, squelch, connections - so you'll at
least know you're not overlooking a very simple solution."

Troubleshooting by comparison

Larry Nolan, fonder of Nolan Avionics, has been using this
trick for the best part of 50 years.
"It's called troubleshooting by comparison," Nolan said. "Of
course, you must have a known-good unit to start, but if you do,
it can save you a lot of time. The first step is to replace the 'bad'
radio or controller in the airplane with your known-good unit. If
that fixes the problem, then you know it's the radio. If not, you
can start working the problem back from there."
Nolan also said that the comparison method is valuable for
bench work. "For example, the manual for a King KX 155 has
a limited number of test points. If you have a known-good radio next to the broken one, you can test everything until you
find the problem."

Troubleshooting by temperature

"Since temperature can cause a number of intermittent issues, another good tip I learned was to use a can of freeze spray
and a heat-shrink gun to selectively freeze or heat components
to see if that recreates the problem," Nolan continued. "It works

Avionics News April 2015

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