LMS 520c back light not working - Lowrance Lms 520c 5" Screen Color External Gps And 200 Khz Sonar System

Select one of the ends of the line using the arrow keys.
Press WPT, Down Arrow, to select Delete waypoint. Then press ENT, left arrow, Yes, ENT.
Repeat for the other point on the line.

First, follow the wire from the fuse to the unit. It may be pinched or cut somewhere between those two points. Seems simple, but this happens often. If the wires look ok, You could also try a fuse one size bigger. If it blows that fuse, then the problem is in the unit, and you will have to sent it out for repair.

two things can be taking place 1 you have a bad key pad 2 you have a bad transducer(short in wire )

read the book that came with it you got to understand how it works and know how to set your unit before you can understand how it works and what you need to do to make it work and to get to what settings you want ..a fish finder is like a computer you got to program it to your likings .. I have a hd 10 structure scan on mine .. .now that's a nightmare to set but the book tells you everything you need to do and how to do it and how to get what your looking for and how to get to it

I have the same problem on my 520C.
I have no solution but I hope you have find some?
Best regards
Dan

Quite often those transducers go out. Not 100% sure but would bet money on it. Call Lowrance customer support and see if the offer any more advised but more importantly see if they can replace your current one as a replacement instead of you having to pay full retail price. I purchased a new gps module through customer support and saved $150 off the normal retail price. Best time to call customer service is at 8:15am central time when the lines are turned on!

I have seen these listed on craigslist from 200 to 400 dollars. I do not know a store that carries them in stock other than the dealer may have it but you will pay threw the nose for it.

Make sure the power is good, and the power connections are clean. Check fuses and connections. You can even get a volt meter, unplug the power cable and test for 12VDC across the two bigger female contacts on the power cable connecter. If you are getting 12VDC, then the LMS-520 is bad. If you are not getting 12VDC, then you have a bad power supply, connection, or cable.

I am guessing that the card you are using is a NAVIONICS chart? There have been some Lowrance units that were made around the same time that have had problems recognizing a Navionics chart right from power up.

Make sure the LMS-332 has the latest firmware version which can be downloaded from http://www.lowrance.com/en/Products/Marine/Full-Size-SonarGPS-Chartplotter-Combos/LMS-332C/Downloads/LMS-332C-Software-Update/

If the update doesn't help, this is going to be a compatibility problem with the LMS-332 and that particular card. You will need to replace the card or upgrade to a newer unit...but probably can just get used to removing and replacing the card when you turn the unit on.

Haven't found any. But the manual covers about everything
http://www.lowrance.com/upload/Lowrance/Documents/Manuals/LMS525CDF-520C_0151-461_120706.pdf

252 pages, you should be able to find answers to any problem you might have with the unit from there.