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got wet. Is it still safe to use?
Andrew Gibbs answers a question from Bill
Andrew, I accidentally left my transmitter
on my car roof overnight. It hadn't rained for about 4
days, but that night it chucked it down! So therefore,
one very damp DX7 was found next morning on the car roof.
First the battery was removed and covers
lifted to reveal very little water inside, although there
was some misting of the display panel. I carefully mopped
up any water with paper towels and put the transmitter
to dry all in the sunshine (indoors!). By some miracle
all seems to work and Tx controls my models perfectly,
including range checks etc. But here comes the crunch
question. Do I fly with it?
I know water and electricity don’t
normally mix, but it being fresh rain water only and nothing
was switched on until all was dry I would like to know
the risk. Many thanks for listening to my tale of woe
and any hints would be much appreciated. And yes, after
all these years I should know better and look after my
kit more responsibly! Bill
Hi Bill, I’m sure you are not the first to have
had this sort of thing happen! You clearly did the right
thing to remove the battery and dry the transmitter out
straight away as an initial response.
I've heard of several cases of cell phones
(mobile phones) being made wet, and these all worked okay
after being dried out. Based on this, perhaps the effects
of exposing your transmitter to fresh water might not
be very significant, though its impossible to be sure.
Let's consider each aspect of the transmitter.
Most electronic components are encased in plastic which
should render them tolerant of contact with water. Another
aspect of this is the possibility of corrosion of metal
parts such as the circuit board and the legs of components.
However, as you say only a little water penetrated the
case, this would also seem to pose a low risk. If the
transmitter interior remained largely dry, in particular
the transmitter’s circuit board and stick potentiometers,
I’d say the risk of a future malfunction from this
area of the transmitter was probably very low.
However, the transmitter was in the rain
for some time, so water may have penetrated the switches.
Any water in here may be difficult to get out, so it may
still be there. The switches are unlikely to be designed
to withstand long term water exposure, so I’d say
this is probably the area of biggest risk concerning a
It's quite easy
to forget about objects placed on a car roof - especially
if the roof and the object are similar in color! (Click
image to enlarge & for more information).
quite easy to forget about objects placed on a
car roof - especially if the roof and the object
are similar in color!
Bill got lucky with
his DX7, the inside of which is seen here. (Click
image to enlarge & for more information).
effects of exposing electronic components to fresh
water might not be very significant. Bill got
lucky with his transmitter, seen here.
salt water is very corrosive. I once took a club
member’s 35MHz receiver which had been crashed
into the sea and it was completely ruined, even
though I rinsed with fresh water within a few
hours. Unfortunately the receiver had already
corroded and never worked again.
I appreciate you are asking for my opinion
about risk and that you understand that I can’t
tell you whether it will be okay to use the transmitter
or not – that is of course your decision to make.
The safest course of action would clearly be to send your
transmitter off to a suitable service facility approved
by the manufacturer and ask for it to be thoroughly checked
out. My guess is that the manufacturer would probably
do four things:
1. Inspect the electronics
carefully under a magnifying glass for any signs of corrosion.
2. 'Soak' test the transmitter
by letting it run for a number of hours (sorry about the
apparent reference to water – this phrase is actually
the industry term used for an extended test under power!)
3. Test the transmitter
electronically for performance – range etc.
4. Inspect the transmitter
for evidence of water damage and replace if necessary
– the cost of this could exceed the value of the
transmitter. Note that it may not be possible to inspect
some items; switches and potentiometers for example may
be impossible to open up without causing damage.
It’s difficult to assess the risk
of continuing to fly with this transmitter, even though
it does appear to work perfectly at the moment. The risk
is of course that the transmitter could stop functioning
correctly while it’s in use at some future date.
Probably the more time that passes with the transmitter
still working, the less the risk that it will malfunction
at a later date.
Depending on what the manufacturer said,
if it was my transmitter, I’d probably write it
off, at least for flying anything other than lightweight
park flyers, as the risk of a future malfunction is unknown.
It may be that you have an insurance policy that would
cover the cost of replacement. Even if not, the cost of
replacement would probably be low compared to the cost
of a lost model, plus – most importantly - there
could be the risk of a model going out of control and
injuring somebody, or worse. If you did then decide to
fly with this transmitter you could start with a small,
light model which represents little risk to passers by
if it crashes and little financial risk to you.
I hope this is of some help. Please do
let me know how you get on.
Kind regards, Andrew