I have an X-52 on the front of my boat and it hasn't showed a fish in the last two months

Besides the fact that I may not be over fish, that is not the main problem. The main problem is the fact that it will work fine for a while and then all of a sudden it will read 120' or 320' when it just read 18' a second ago. Now either I am hitting some heck of a drop offs or something is wrong.

I checked the wires and cleaned the transducer, but nothing seemed to help. Shutting the power off and turning it back on sometimes fixes it, but usually it takes about 3 minutes for it to start reading the correct depth.

Anyone know what might cause this or how I might go about getting it fixed? TIA.