Lowrance LCX-25c Eratic Sonar Readings

[Belchy]

Two years ago, purchased this unit and everything went good for year and a bit, end of last season mid september, started getting eratic readings on the sonar, example being in 30+ feet of water and the screen telling me i am in 3 feet, screen would also be one solid colour. Just wondering if any one has any ideas of what might be causing this. I am thinking of starting with checking to see if the transducer cable is crimped, come loose, any other pointers would be great. it is a 200kHz.

Thanks

Belchy

 

[Boatist]

Re: Lowrance LCX-25c Eratic Sonar Readings

Great Unit.

Some basic questions to get a little more information.
What color is it displaying?
Does it happen while going very slow or only at higher speeds?
Turn on the digital data and display the voltage, what is the voltage?

Without more information all we can really do is give you some basic things to check.

1: Check the transducer it self, Is it pointing straight down? Is there anything in front of the transducer that would cause air bubbles or turblance? Clean the transducer with dish soap and water on a soft cloth, Make sure to flush with clean water. Any scratches or nicks or cracks or barnical on the transducer?

2: Check the transducer cable and all the connection along the way. Make sure they are tight and make sure the contacts are clean not green color.

3: Check the power cable the same way from the unit thru the fuses all the way to the battery. Check the power at the unit with a volt meter or turn on the digital data and the voltage. Should be 12.6 volts or more.

4: Reset to factory defaults.

5: If it still fails disconnect the transducer at the unit and turn it on. See if it still has the problem. Some units will go into demo mode with no transducer. If it looks good with out the transducer then see if you can find a friend with the same type unit or power and transducer connections and test the power head on their boat. See if you can find a dealer that will let you test the unit at there shop with one of there transducers and agree to buy the transducer if it fixes the problem.

6: Call Lowrance with as much information as you can gather about how and when it fails. What it looks like when it fails. You can not give them too much information.

7: Most important of all when you find the problem come back and share it with us so we can learn more and help someone else.

Good Luck

 

[Belchy]

Re: Lowrance LCX-25c Eratic Sonar Readings

Colour I was mostly getting way yellow with a bit of orange at the bottom. At that time the digital depth would be flashing in the corner of the screen.

Within the digital data display, I was getting a solid 12V of power.

It happend at speeds anywhere from 1.4-2.6MPH, (GPS recorded) when I was using my 9.9 Yamaha Kicker. I wonder would the spark plugs in this motor be causing any of these issues? It doesn't seem to be an issue when the 5.7 OMC Cobra is running.

I am going to check the the rest of the list you gave me, hopefully this week when I move the boat indoors into heated storage until spring thaw.

Please let me know any more thougths that you have, they are greatly appreciated.



Thanks

Belchy

 

[dingbat]

Re: Lowrance LCX-25c Eratic Sonar Readings

I had a 16C that did something similar. Turning up the gained helped at times but in the end I ended up replacing the transducer and the problem went away but this sounds a bit different.

Your getting the flashing depth display which tells you it's a lack of signal. You should be getting a good solid red bottom return as well so that's telling me that you have a week signal.

The fact that it only occurs with the kicker running would led me to think that you have a battery issue. The unit's not getting enough current to drive the transducer fully.

You say you have a solid 12V but that's on the low side. A good battery should provide more than that. Check to see how much voltage with the big motor running and with the big motor off.

The big motor would be supplementing a border line battery where as a kicker would not. I bet if you run both motors together your problem would go away.

 

[Boatist]

Re: Lowrance LCX-25c Eratic Sonar Readings

Yellow is actually the strongest return so try turning down the sensitivity.

A flashing depth reading means it does not know where the bottom is.

Motor with stators chargers and tach signals can cause a lot of electrical noise.

Was the Yamaha motor added since the unit last worked good?

If so try isolating your power and transducer cables from the other cables running to the back of the boat. Wire you LCX 25 all the way back to the battery, ofcourse thru the proper fuses.

If still have problem try adding some filters to the power cable. Start with some Farite Beads and then try a LC filter like use for a radio.

The unit is designed to run on 13.8 volts but should work from about 10 to 16 volts.

Good Luck

 

[Belchy]

Re: Lowrance LCX-25c Eratic Sonar Readings

Thank you for all the info. I have now relocated the boat indoors in a heated garage so that I can start to straiten this stuff out, however it won't be till ice out that I will have a chance to test it.

Yes the Yamaha was installed before the sonar, and for a year they both seemed to work great.

But I will keep you informed of how it goes and what happenes when it finally gets back in the water.

Thanks again for all your help

Belchy

 

[watermellonI]

Re: Lowrance LCX-25c Eratic Sonar Readings

when i installed my 16 lowrance recommended pluggin and unpluggin to help clean terminal connections between the head and transducer and they were emphatic about connections to the transducer staying clear of motors or other noise.