Clipper echo sounder broke

[Danny]

My Nasa Clipper echo sounder decided to give up this week. It insists on saying 'OUT' instead of the depth. The manual (shows I'm getting desperate) says this means it's not hearing an echo. Now - does this mean the transducer is broke or the instrument head.

I checked the DC resistance of the transducer and it appears to be open circuit. Anyone know if that's normal for one of these? I'd like to be sure it's the transducer before I cough up for a replacement.

Any ideas on how to check?

 

[hightech]

You are unlikely to be able to measure any resistance as it is a Piezo crystal, they need to have a frequency applied to see if they resonate.

Is the transducer thru hull or in hull?? If in hull, check if the bonding is still intact and there is no air gap.

I have seen a couple of transducers recently where they sounder shows a bad/no depth and the transducer is no longer attached to the hull or the oilbath has expired.

 

[bobgosling]

This can happen if the transducer is mounted in an oil filled tube and the oil dries out. Clean out tube contents and refill with baby oil.

 

[graham]

i had that with mine.A slight leak where the tube is bonded to the hull let the oil out gradually. I used cooking oil in mine as I had it aboard.(Still OK after 2 or 3years).

Im not sure if barnacles or weed on the hull could be the cause?

 

[simon_sluggett]

my clipper echosounder occasionaly says OUT but otherwise works fine, is this an indication of a problem coming.

For a replacement unit try this guy here

http://stores.ebay.co.uk/Online-Marine-Mart
I bought a duet unit and saved loads.

 

[Danny]

Thanks everyone. It's fitted in-hull but I've checked the oil level. It was still OK after 3 seasons. I emailed Nasa after I posted and just received a reply from them. They reckon it's probably not the transducer at fault. They also confirmed that the transducer will appear open circuit to DC.

They're only a few miles away from me and have offered to check the instrument head if I bring it in. Problem is that I left it on the boat - 90 miles away. So it'll have to wait a week or two.