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GA Bassman

Lowrance LMS 520 Sonar/GPS problems HELP!

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I just purchased a 520c Lowrance sonar /gps and it does not perform well.    I purchased it from Online Marine without checking them out and now I find that I can't return it.   Dumb mme.

The machine will noot hold bottom when passing over weeds, even weeds that are several feet under the boat.    It gets a scrambled signal which is unreadable.   Most of the time it will not reset and I need to shut off the sonar and restart.   Even then is often will not recover the bottom.

Lowrance is aware of the problem and has issued at least two firmware upgrades.  I have installed these at their suggestion but it only got worse.

Has anyone here used this GPS / sonar and experienced similat problems?  Have you resolved them?

The GPS portion is about as worthless as it continually looses the satallites and just gives me a diaalog box saying thhe GPS is not functioning.

Guess I may just be out $650 bucks on this poor unit.

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I can't speak for the Sonar  other than to sugggest you deal directly with Lowrance.  As for the GPS, if I'm not mistaken, the 520 requires an external antenna.  If you don't have one that could be your problem.

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A little more info may get you some better responses.  Where is the unit mounted trolling motor, or transom.  How old are your batteries.  Is the unit getting enough power.  Where did you mount the gps reciever.  Who did the install?  Is the transducer in clean water or is it getting bubbles from the boat.  Are you running another unit at the same time.  I think you can work this out but we need more details.  

What has Lowrance said about the unit.  Send it back to them if you can.

Good Luck,

Tom D.

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http://www.lowrance.com/en/Products/Marine/Full-Size-SonarGPS-Chartplotter-Combos/LMS-520C/Downloads/LMS-520C-Software-Update/

Did you install 2.3 ? That fixed it for me.

Try talking to this lady.

Linda Colt

Customer Service Department

12000 East Skelly Drive

Tulsa, Ok 74128

1-800-324-1356 #8747

Direct line 918-438-8747

Fax 918-234-1745

Email: linda.colt@navico.com

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My LMS 520c is mountedd on the bow.    It has the external antenna which is also mounted on the bow with pretty much unobstructed view of the horizon.  I can place my Garmin handheld in the same location and never lose GPS .  I did the intsallation.   The unit is getting 12.7 volts with battery fully charged.   I am using the MinnKota trolling motor transducer with proper adapter.

I have uploaded the latest software 2.3 from Minnkota's website as per their(Lowrance tech) recommendation.   It might have made a minor provement  though it would be difficult to prove.

It has excellent bottom deffinition over rocky or any bottom so log as no weeds are present.   It absolutly will not register bottom over a Milfoil weed bed or coontail weed bed.   It has limited response to bottom over hydrilla.   When bottom is lost I generally need to shut down and restart the unit.  I will find bottom but lose it almost immediatly if I am still over the weeds.   Weeds simply confuse it.  During the few times it has maintained stability over a weed bed it indicateds the weeds to be bottom as they are bright yellow just as is rock bottom.  A few strands of milfoil will appear on the screen as a bright yellow peak.  The unit gives a very nice readout of bottom when no weeds are present.

I re-installed my old Hummingbird 400 TX and it holds bottom perfectly over the same areas so I am using that most of the time.

I am fishing Lake Seminole in GA.   I have a couple buddies that also recently purchased Lowrance units and they are experiencing the same troubles.  Scrambled signals when getting over weed beds.  

I called online marine to return it but they refused even though I only had it a week.   Lowrance is aware of weed problems but only has the Software 2.3 update which is a very limited fix.   I will call them again to inform them of the negative fix.    This unit is pretty much useless as is.  Guess I will have to bite the bullit and acept my loss.  My experience indicatess  I should have purchased a new Hummingbird.

thanks all for the inputs.   I got far more from this forum than onlinemarine and Lowrance.

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If you have to keep it, mine  did the same thing. Fix it by putting your skimmer on the TM,..I know you got a universal but so did I and they don't work that well on MK's.  Second put your antenna back farther on the boat...at least 3' away from unit. You'll burn out your external any closer to your unit. Lastly if you need help and your close to Santee SC next week run it over to Wilson Frazier. (Lowrance guru @ the comp wagon)

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I was going to suggest using the transducer that came with the unit not the universal one.  I think it was basssmaster that had an article about motor guide and lowrance and how they had worked together to get the units working.  Don't know about Minnkota.  Try with the Lowrance transducer and see what happens.

Tom D.

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hey billy bob, what did you mean by "you'll burn out your external any closer to the unit". I ask because i have a lowrance 320c, after i installed it the gps worked one time and then quit and hasn't worked since. The gps antenna is about two feet from the unit.

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I spoke with a local MK repairman and was told the universal transducer has been causing problems with some sonar units. He suggest switching to the transducer supplied with the unit. He also felt confident this would fix the problem.

I have a LMS332c mounted less than two feet from the antenna and have not had a problem in  3 years of operation. Billybob has stated this is a problem in past threads but has not responded to questions. I can not find any mention of this in the Lowrance installation manual. Possibably this could be a problem if you shorten the cable running to the antenna. Impedence matching? I did not shorten my cable. I am curious to the source of his info. Maybe he will respond to questions this time........................Al

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Today I emailed Lowrance and again explained my installation and problems.   They are trying to help.   Said they are sending me a new unit as well as prepaid shipping to return the problem one to them. Hard to find fault with that service.

My receiver module is about 18 inches from the main unit.   Cable is original length so imepdance is as manufactured. I can not locate any instruction that mentions installing it 3 feet or more away.  I could move it away but do like it's present location.   I will try a new distant location if the new unit presents same problem with GPS reception.

Will let you all know what happens when I receive the new unit.  Will hope for good operation in sonar as well as GPS functions.

Thanks for thee help.

I will hope that my original unit is defective and the new one will operate as Ihoped.

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I purchased my 520c with no transducer so have to assume the MinnKota is OK.   I did let Lowance know I was using MinnKota's universal transducer and they had no issue with that.    It would be interesting to see if it performed well with it's designed Xducer.

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Ga Bassman, glad Lowrance is working with you. Please let us know the results.

I believe Lowrance would tell us in the installation manual if the antenna had to be mounted over 3 feet from the main unit. My lms332c is mounted indash and the antenna is beside the dash without any problems.

Good luck with the new unit and keep us posted..................Al

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I know there is no mention in the book about distance but several times on the open tour I've had problems, taken it over to the trailer and both gurus Capt. Mike and Wilson Frazier have said get the external off the bow next to a 330c, then 332c, and now a 520. There are units its okay with, but most non-hard drives its not. Has nothing to do with the cable length and at the price of the antenna, its not worth the risk. Triton factory setups stopped putting the antenna anywhere but in the back. I just tried to get them to do a beside the console on my new boat. I'm just repeating what they told me, and both these guys know more about the units than anyone else.

 If you have the skimmer GA you won't have anymore probs.  And Al I had a external 12" from a 332c  on the bow for two yrs, before she blew out.  I learned the easy way...every things complimentary on the tour, the hard way is when its out of your wallet. I've seen Wilson change dozens of antennas each tournament. Thats always the fault, or so he says.  Just advise is all I'm offering.

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Sounds like advice worth considering.   I did ask and do appreciate all inputs.   Better to relocate the antenna module than risk a failure from that possible cause.  Got plenty of cable on the unit and one more small hole will not be a problem.

Thanks for you input and time.

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Sounds like advice worth considering. I did ask and do appreciate all inputs. Better to relocate the antenna module than risk a failure from that possible cause. Got plenty of cable on the unit and one more small hole will not be a problem.

Thanks for you input and time.

I agree, thanks Billybob for responding and the advice. I will start looking for a new location..............Al

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Today I emailed Lowrance and again explained my installation and problems. They are trying to help. Said they are sending me a new unit as well as prepaid shipping to return the problem one to them. Hard to find fault with that service.

My receiver module is about 18 inches from the main unit. Cable is original length so imepdance is as manufactured. I can not locate any instruction that mentions installing it 3 feet or more away. I could move it away but do like it's present location. I will try a new distant location if the new unit presents same problem with GPS reception.

Will let you all know what happens when I receive the new unit. Will hope for good operation in sonar as well as GPS functions.

Thanks for thee help.

I will hope that my original unit is defective and the new one will operate as Ihoped.

I did get a new unit from Lorance. It has newer software installed, version 2.4 which has notyet been released to the public. This unit is better but still loses bottom over milfoil weed beds. It will though , unlike before, still give a bottom line as the chart now keeps running unlike the older one where the chart stopped scrolling. Perhaps another look by teir programers will resolve the bottom losing issue over weeds.

I will be sending LowrANCE SOME OPERATION REPORTS NEXT WEEK FOR THEM TO PONDER OVER.

The GPS on this new unit works fine and holdsthe sattellite contact well so far.

Lowrance it trying to help resolve my promlem so hats off to them for caring.

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I have 2 lowrance lcx-37c with the same problem.  Both are running the new 2.3 version of software and I've already replace the LGC-3000 without any luck.  Lowrance said the same thing, that my gps puck was too close to my console unit.  I believe this to be bogus since it has worked for several months and just started doing position lost a few weeks ago.  I have found by turning off one of the units the other will instantly aquire position.  I have checked and rechecked wiring without any luck.  Have you had any luck resolving this problem?

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How far away is your GPS puck and what version of software are you using?  I have both networked together using the same LGC-3000 unit.  Both will work fine for several hours then they decide to lose position.  I checked to see if it is picking up satellites and both are but position will still be lost.  I can power one of the units off, doesn't matter which one, and position acquired with instantly appear and I will never lose position again unless I power up both units at the same time, but this will take a few minutes before position will lose again.  Power off one unit instantly GPS acquires.  Don't understand it.  Any help is greatly appreciated.

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