Lowrance 5200c

I have a 5200c that the light power button stopped working on... When you turn the main power on the boat it use to come on and now it loads up the first global map screen then goes black and has a few little symbols that jump around on the screen. I looked at some heads but can not find anything less than 200$. I need advice, choke up the money for the head or send it to the factory for repair if possible or breakdown and buy a new unit.... Thanks ahead for any advice

I had a 520 c igps.it was a great unit but I ended up with the same problem. I think water might have gotten into it. I ended up buying one from a guy on another forum for like $275. I have bought an HB1198 after that but plan on keeping the 520 on the front of my boat.

No repair available for units that old.