I've had this 7SV about 3 years. The boat is always in the water. It has worked well until recently. Nothing has changed with the boat, transducer, or settings.

 

It has begun to sHow about 1-1/2 feet of surface noise at the top of the screen as a yellow band. I can turn the noise filter "on", and disappears. I do t mind that, but I'm wondering if it's related to this problem: it no longer locks on and shows depths less than 8.8 feet. Anything below that, and it just flashes the last known depth. It does this, even with the engine off and no boat movement. The transducer is clean. When I move to anything more than 8.8 feet, it locks in an works correctly. Again, I never saw the yellow band at the top until this started. I've reset to factory sonar defaults, no change. The transducer is a GT52HW. 

 

Have any of you experienced this issue?

 

 

I've occasionally noticed those things on a sticker 9SV, but they always go away before I'm troubled to go into the setting and mess around.

 

I've never had the problem where it won't show depth reading though, but the clutter up top and occasional blinking on the depth have happened.    I always though it might have something to do with the bottom composition because the blinking depth thing happens when I usually over very soft muddy/mucky bottoms.   To me this makes sense because the return isn't as hard as when it's hitting rock bottom for example.   

 

Maybe try cleaning the transducer really good since you said it's been in the water for 3 years.    Mine has been in the water that long though as well but I also store the boat with the motor/transducer out of the water.  

Might also try taking the unit out of “auto” depth range if you haven’t already and see if that makes it read normal in shallow water again. Some of the Lowrance’s used to have that issue from time to time, and that usually solved it. 

Ok, I've had somewhat of a breakthrough with a workaround. For some reason, this issue is related to the lower frequencies of traditional sonar and my transducer. For nearly 3 years, the system has been working fine at the factory defaults.

Yesterday, I switched to ClearVu (455khz) and I can now read and lock on to the bottom as shallow as 1.2'. I can also read depth at 80+' and see activity while at 20mph, something I've never been able to do on the pontoon boat in traditional sonar mode. This isn't a "fix" for the original problem, but it does allow me to keep using this setup for the time being.

I'm beginning to think there's a problem with the lower frequency part of the transducer.

you're probably right that the lower frequency piezo is having an issue, maybe a broken wire.  Either way, you're better with the higher frequency anyway.  You'll get clearer returns in most all scenarios with it.

On 5/2/2025 at 9:54 AM, casts_by_fly said:

you're probably right that the lower frequency piezo is having an issue, maybe a broken wire.  Either way, you're better with the higher frequency anyway.  You'll get clearer returns in most all scenarios with it.

Gonna run it a bit and see how I like it. So far, ClearVu seems to generate better returns on cover and fish, just used to the old school classic sonar screens. 

On 4/30/2025 at 9:48 PM, Team9nine said:

Might also try taking the unit out of “auto” depth range if you haven’t already and see if that makes it read normal in shallow water again. Some of the Lowrance’s used to have that issue from time to time, and that usually solved it. 

Thanks, I tried that, but no change. Going to ClearVu mode at 455khz seemed to solve the problem, so I'm thinking there's a problem with the low freq sonar part of the transducer.