Hey Tim, happened to be browsing the frum and saw this. I have to tell you about my experience with the Hook2-7 TS.
I purchased one, installed on my old boat, and used it for walleye opener last year. After a few days it started doing exactly what you say, as well as losing it’s ability to track me on the GPS page (it would not keep up with where I was, it was about 30 seconds behind). At first it only affected depth at speeds above 20mph, but eventually it stopped “seeing” the bottom altogether.
I moved the ducer 3 times and had a shop confirmed it was in the correct location. They were happy with where I had it. Took it back out, the problem persisted.
Then I bought a new boat. Brand new, off the showroom floor. Brand new batteries, everything new. Decided I’d give the Lowrance another shot thinking maybe some shoddy wiring in the old boat was causing some problem. Nope, same exact issues.
Then Joe’s sporting goods gave me a new head unit, free, because Lowrance refused to exchange. It worked great! for a week. Then I watched it happen one day, out on the ST. Croix. It just shut off. I went to turn it back on, and it was very very hot to the touch. AFter finally getting it to turn back on it would not work again, same 2 issues (GPS and bottom). Documented the problem, Lowarnce again told me to blow smoke. Joe’s let me exchange straight up for a Helix 7 G2 SI. I’m happy now, but I really liked the Lowarnce format. Too bad their custoemr service ruined me as a customer. SOld my elite 5 as well after that just so I don’t have their brand in my boat any longer. The best they offered was I send in my unit, with $150, and wait 12 weeks while they look at it. IDK about you but I’m in MN. We hardly have 12 weeks of summer to begin with.
The service is inacceptable. the product, when and if it works, is amazing and a great value. I won’t be going back though. Maybe one day I’ll try Garmin, or Raymarine, or something else. Hbird nickel and dimes for every last thing it is infuriatingly expensive to rig out your gear. But at least it works well.