# Lowrance fish finder



## StewDogg (Sep 26, 2014)

I have a Lowrance LMS-520. Fish finder/GPS. When moving across the lake the screen is white with a grey bottom.And also says 31F.T . of water. Next thing I know the sreen scrambles and turns blue,purple, and pink.The depth now reads 1 F.T.. A short time later it goes back to the white and grey screen. Also I am not marking any fish on the sreen.I adjusted the sensitivity up and down no luck. I not marking any fish at all.Funny thing is two fishing trips and we were catching perch.The screen should have shown some fish.The only thing I see in the bottom. This unit was purchase back in 2007.Can anyone out there help me. Should I call Lowrance.How long due these fish finders last? Please help .:B thank you.


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## polebender (Oct 29, 2011)

Are you having problems with the maps/gps screen also? If not, it sounds like it may be transducer related. Do you have through the hull transducer or mounted on the outside? If it's on the outside, try to wipe it off. You can also use a fine grade sandpaper on it. Over the years a film can build up on them and cause problems with readings if you don't check it periodically. Also check the positioning of the transducer. Sometimes if you hit something it can knock the transducer off balance.


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## K gonefishin (May 4, 2004)

Sounds like a bad transducer


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## StewDogg (Sep 26, 2014)

Pole bender, K gonfishin . The transducer wire runs thru the back of the hall.In the spring I will try to clean the eye of the transducer with some sand paper. The gps seemed to be working .Is there any thing I can due over winter to see if it is the unit? Or do I just replace the transducer? If I don't replace the transducer.Will I be able to tell if the unit is working right.Out of the water. Dry docked. Or do I have to have the boat in the water. I would hate to have to pull the boat back out of the water after i launch for the season. Thanks Guys for your advice.stewdogg


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## polebender (Oct 29, 2011)

If I were you, I'd contact Lowrance just to get their opinion! It's a free call and free advice! I'd ask about cleaning the transducer and see what they say. The only other way would be to take it to a marina where they could submerse it and test it. It doesn't sound like its the unit, or you would be having problems with the gps also.


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## K gonefishin (May 4, 2004)

IMO I would just replace it. They aren't that expensive and if the unit is working and GPS is good that even confirms it further, mever heard of sandpaper sounds abrasive Soapy water and sponge sounds more like it. The only thing you can do out of the water is listen to the ducer to see if it's clicking. 

Give them a call though.


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## polebender (Oct 29, 2011)

K gonefishin said:


> IMO I would just replace it. They aren't that expensive and if the unit is working and GPS is good that even confirms it further, mever heard of sandpaper sounds abrasive
> 
> Give them a call though.


I agree with replacement. It is an older unit. It sounds to me that he wants to test before replacing. The first fish finder I ever bought, which was years ago, they recommended that you use a fine grade sandpaper on the bottom of the transducer to remove any factory film and said it would also aid in the readings.


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