Navman Fish 4150sx anomaly.

[Major Catastrophe]

First time back into the water since the long lay up/repair and my Navman fishfinder has thrown a wobbly. The transom mounted transponder unit is undamaged and untouched, in that it hasn't been moved out of its fitted position yet is it offering me spurious depths.

After launch it told me that I had 11 metres under the keel, which was interesting as I could see the bottom and it was no more than three feet, and then it started showing what cound be the real depth, but kept flicking to a very shallow depth, so that I had to turn off the shallow alarm.

As you can see from the pics it flicks from 15 metres to 0.8 metres and it also does it when stopped.

I have pulled out, refitted and joggled the connections, but want to know if this is likely to be a unit, wiring or transponder fault.

 

[JKay]

Are you ready Major

With the fishfinder on Gently No fondly clasp the transducer

if it pings its ok

I just sorted two of my mates depth sounders by sorting out

the "Offset"setting

Good Luck

cheers Joe

 

[Neddie_Seagoon]

Check the earth connections on the circuit - it may simply be poor battery grounding.

 

[Major Catastrophe]

[ QUOTE ]
With the fishfinder on Gently No fondly clasp the transducer

if it pings its ok

[/ QUOTE ]

If what 'pings'? Is this a sound, or a register on the display.

Steve, good point about the earth.

 

[msutton]

I have the same thing happening on a 4150sx. Did you solve your problem?

 

[samattrill]

Hi,

does anyone know where to get the plugs (both power and the transducer) from?

Thanks

 

[Major Catastrophe]

[ QUOTE ]

I have the same thing happening on a 4150sx. Did you solve your problem?

[/ QUOTE ]
Only just seen your post MichaelOnTheClaraMae.

No, I haven't solved it. Navman tell me that it is the angle of the transducer. Well, my transducer hasn't been moved for two years before the fault started and I have checked that it is still at the correct angle which means that the forward part needs to be slightly higher than the trailing edge so that the signal is projected slightly forward. I presume this is so the boat doesn't go so fast it 'misses' the return signal.


[ QUOTE ]
Hi,
does anyone know where to get the plugs (both power and the transducer) from?
Thanks

[/ QUOTE ]
samattrill, I asked a dealer about that and he said the two best places were either a Navman dealer or the boat where the Navman display was originally nicked from!

 

[duncan]

looking at the posted pics and text the unit is reading surface clutter as depth in that one if it's on auto sensitivity try resetting to 80% in the shallows and see if this clears it / or have you a surface clutter / noise reduction function?

agree with others that it may well be a reflection of variable voltage/current reaching the unit as well

 

[Major Catastrophe]

[ QUOTE ]

agree with others that it may well be a reflection of variable voltage/current reaching the unit as well

[/ QUOTE ]

Funny you should say that. Even though I have checked the circuit - twice - and loosened and re-tightened all the connections, including the earth. Sometimes it will be constantly flicking between depth and surface readings and at other times, only every ten to 45 seconds. It can even work okay for several minutes.

But the other week, when I was pretending to fish, it gave up altogether whilst I was at anchor for five hours with engine switched off and reverted to the two dashes. I thought it was becasue I only had two feet under the keel and it cleared back to the occasional flick once I was under way. Couldn't figure out if it was the shallow depth causing the problem, or the drop in battery voltage.

Battery is in tip top condition.