Help me, Larry Fisher, you're my only hope...

Joshua Anderson

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Jun 6, 2006, 2:52:20 PM6/6/06

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On the job yesterday, an actor mistakenly let a UM400 fall to the beach
just as the tide was coming. The transmitter was picked up quickly, but
after a small wave of salt water grazed it. I wiped the unit down and
let it air out. I haven't tried it yet. I worry that even though I try
it and it seems to be running correctly, that the damage may be
corrosive and show it's effects much later.

Is this a "have production send it in for a look" or "if it works, it's
still good" kind of a situation? I told the producer that even though I
don't think water got inside, contact with salt water is probably one
of the worst things that could happen to an eletrical unit.

Thanks, Larry.

Josh Anderson

Scott Farr

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Jun 6, 2006, 3:12:09 PM6/6/06

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You should have opened it up and rinsed it with bottled water. Send it
in for service.

Eric Burge

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Jun 6, 2006, 3:45:43 PM6/6/06

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Not to shortcut Larry's reply as he is the man when it comes to Lectros
and most things RF, but I will offer some generic advise regarding
saltwater and electronics.

1) If something electronic gets swamped in salt water, remove batteries
ASAP!!! If you have charged capacitors soaked you may be SOL, but
still, do what you can to remove current from all circuits.

2) Rinse/soak in distilled water to remove salt residue.

3) Dry with very warm (not HOT) air as with a hairdryer. Avoid a heat
gun unless it's all that's available; you don't want to melt any
delicate stuff.

4) Spray liberally with DeOxit or similar board cleaner.

5) Reassemble and test.

I've saved radios, cameras, and various other electronic gear doing the
above. The critical phase is the time logged between exposure and
removing batteries. Hot, wet circuits will kill you every time.

If you're fast enough, you may even avoid a trip to the factory
doctor...ar at least get you through the rest of the job.

EB

Larry Fisher

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Jun 6, 2006, 4:00:48 PM6/6/06

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Hi Josh,
We have FAQ #23 for units that went swimming.

http://www.lectrosonics.com/faq/faq1byref.php?id=23

Fortunately, you got to your unit pretty quickly and soaking the unit
was hopefully not necessary. I would now open the UM, separate the two
boards and look for any evidence of salt crystals or metal corrosion.
If there is ANY evidence that salt water got into the unit, then you
will have to clean the unit. Rinse the board(s) in alcohol as
discussed in the above FAQ. If there is any corrosion, try to rinse it
off and/or brush the corrosion away using a stiff brush moistened in
alcohol such as a cut down acid brush or a toothbrush. If you have
corrosion on the RF board particularly, the prognosis is not good. The
audio board is more tolerant.
Best Regards,
Larry Fisher
Lectrosonics

On 6 Jun 2006 11:52:20 -0700, "Joshua Anderson"

Larry Fisher

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Jun 6, 2006, 4:12:58 PM6/6/06

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Good advice from Eric.
Also, let us know how you made out.
LarryF
Lectro

On 6 Jun 2006 11:52:20 -0700, "Joshua Anderson"
<jos...@productionsoundmixer.com> wrote:

Eric Burge

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Jun 6, 2006, 4:29:02 PM6/6/06

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Oh yeah,

>Rinse the board(s) in alcohol as

>discussed in the above FAQ. <snip>

...what a waste of a good martini!

I've seen good results with DeOxit, but I'm waiting for TSA or other
mean people to confiscate my travel supply. Then it'll be all about the
vodka for sure.

Any data on listing a liter under expendables? <g>

EB