Thread: 778c problems

I bought a a 778c and I have been having problems with it reading crazy. Showing fish at one depth and then jumping up to a shallow depth. It has been cutting off?? I have checked the connection and it is fine. I have called HB and they told me to cut down my fish sensitivity and raise the noise filter up, I have done that and had no luck. I was going to add the GPS to it but since I have had these problems with it, I don't know if I want to spend the extra money for it. If anyone has any suggestion please let me know. I'm going to call HB again in the morning.
Thanks,
Lynn