Fish finder transponder - How do I test?

[Russell Griffiths]

Greetings group.
I have a Humminbird "Wide One Hundred" fish finder.

Can anyone tell me if the transponder can be tested with
a multimeter or other test gear?

A continuity test shows it to be open circuit.


The unit also would not turn on, I have found the power button
in the rubber keypad is crook, not sure what to do about this yet.

Thanks,
Russell Griffiths.

 

[John Crighton]

On 18 May 2004 19:18:34 -0700, rg26ce1991@hotmail.com (Russell
Griffiths) wrote:

Greetings group.
I have a Humminbird "Wide One Hundred" fish finder.

Can anyone tell me if the transponder can be tested with
a multimeter or other test gear?

A continuity test shows it to be open circuit.


The unit also would not turn on, I have found the power button
in the rubber keypad is crook, not sure what to do about this yet.

Thanks,
Russell Griffiths.

Hello Russell,
the easiest method I have found to test the transducer
is by substitution.
Compare the performance with a known good one.

A long time ago I worked for AWA. In their marine workshop
at Leichhardt there was an old backyard style water tank
without a top about 6 feet high, a fathom, just over a brachia,
the distance between an Italian fisherman's fingertips.
From a lump of wood hung various transducers of the various
echo sounders and fish finders that AWA sold. Their faces
just in the water.

A customer with a problem would bring in his suspect
transducer and echo sounder and the performance of
his transducer could be compared with the known good
one. Lots of re-echoes on the sounders chart paper or
whatever display it was gave a good indication of performance.

Unfortunately with a digital readout indicator you can't
do this simple test. Is your echo sounder a digital readout
type?

With popular sounders you are very likely to meet
someone at your marina with a similar sounder.
Hook up a temporary small battery to your echosounder.
You ask if you can bring your battery operated sounder
on to his boat and use his transducer.
Compare the performance of your sounder with his.
Now you know if your echo sounder is working or not.
Digital readout is a problem. You can't see re-echoes.
Other displays will show many re-echoes and you can
compare the number of re-echoes on your sounder
with the other echosounder.

If you have your transducer with you, check if it performs
on the mans boat with his sounder also.
Hang it over the side of the boat in the water.

You could take your temporary battery powered sounder
and transducer to a swimming pool and see if its gives
a reading across the pool at the deep end.

Where is your suspect transducer mounted?
Inside the hull or outside the hull in the water?
Just checking that an inside the hull mounting,
is not causing you a headache.

Sometimes, an AWA customer would bitch like crazy to
the management about his badly performing echo sounder.
I would be ordered by top management to go for a run out
to deepwater on AWA's executive piss up boat, Dameeli,
with the customer and test the sounder and transducer with
a known good one and prove to the customer that his unit is
working and suggest that perhaps he has an installation
problem. I enjoyed those jobs.
So did the the customer, if you get my drift.

Regards,
John Crighton
Hornsby

PS
Russell, how did your desoldering tool repair job go?
Success, I hope.

 

[David L. Jones]

rg26ce1991@hotmail.com (Russell Griffiths) wrote in message news:<13cdb672.0405181818.6379fbb7@posting.google.com>...

Greetings group.
I have a Humminbird "Wide One Hundred" fish finder.

Can anyone tell me if the transponder can be tested with
a multimeter or other test gear?

A continuity test shows it to be open circuit.


The unit also would not turn on, I have found the power button
in the rubber keypad is crook, not sure what to do about this yet.

Thanks,
Russell Griffiths.

It may be a piezo-ceramic transducer, so try measuring the
capacitance. The cap value should be a lot more than just the cable
capacitance for instance. A rough guess might be in the order of 100nF
maybe...
It would only be a go/no-go test though.
I believe fish finder transducers work at a few hundred KHz.

Regards
Dave