Ok, I had a Lowrance Hook2 that my brother now has since I upgraded. The unit was only 6 months old and worked perfectly when I took it off my boat. I had it transom mount and he mounted it on his trolling motor. Like I said, it was set and working perfectly when I took it off my boat. We took it out yesterday for the first time since he hooked it up and it was a total disaster as far as picking anything up. The photo attached is what the screen shows constantly! I tried readjustments but nothing would change it. The transducer "appears" level. Any suggestions on what I should do to correct this issue?

It looks like interference.  How is it powered?

It is hooked directly to a battery which also has the trolling motor connected to it. That battery is connected to another battery in the back of the boat. He had an older model monochrome on it before and didn't have a problem.

My electronics are connected to my cranking battery. I’ve alway read they shouldn’t be connected to the TM battery but that could just be hearsay. 

What it might need is a filter - that's what I had on the canoe where everything was connected to a single battery...TM, Sonar, cameras...all of it. Lowrance Hook 2 and later a Garmin Striker 7cv never gave me issues. Filter goes on the power line to the sonar.

https://www.amazon.com/ferrite-core-filter/s?k=ferrite+core+filter

Thanks MN. We will definitely try this and see if it helps. At this point I'm about ready to try anything!

Trolling motors are the number one cause of electronics interference.

Hi, I'm MFowler's brother, the one with the Hook2 4X.  I might add that this unit does this even if the trolling motor is not running or is unhooked from power.  I wired the unit to a separate battery this morning and get the same picture my brother posted. At this point he and I are both clueless.

Can anyone tell me if the Hook2 has auto shutoff function?   If I leave the power on either because I forget or screen is darkened and I can't tell it's still on, will it run down my battery?

I think it will drain your battery.  I don't believe it will automatically turn off in time to save a battery.   

 

On 8/1/2022 at 11:21 AM, VTFan said:

Hi, I'm MFowler's brother, the one with the Hook2 4X.  I might add that this unit does this even if the trolling motor is not running or is unhooked from power.  I wired the unit to a separate battery this morning and get the same picture my brother posted. At this point he and I are both clueless.

Probably a bad transducer.  It might have gotten damaged in the switch.  These transducers have crystal piezo elements in them that are prone to cracking when hit too hard.  They're not as robust as the more expensive models, in my experience.