Lowrance M68 trouble

[icemanhunting]

I have a M68 that in the ice machine mode using the flasher the depth keeps bouncing.I am in 35' of water and the unit keeps bouncing between 29' and 35'.It makes it tough to see the jig as well as the fish.I email Lowrance last Wed.and have yet to receive a reply.I also did a hard reset and it said PORT 1 FAILED.