I’ve got an 859 doing the same thing. Called Humminbird and they told me to send it in for the flat rate of $300+.

Fisherman-j did you get yours fixed without sending it in?

Thant’s two humminbirds that are not working for me. One 1198 with 200 hours that the GPS went out on – $500+ to fix and now this 859 that they’ll cost $300 to fix. I use my stuff very infrequently and gently.