HB depth problem?

I have had a problem with my Humminbird reading the correct depth. I lost my head unit a while back, so I ending up buying a whole new unit. I had this problem before with my old unit. I replaced the transducer, and head unit, used the same base and power wire that I had already installed. While on the lake for a couple hours, everything works fine. And all of a sudden, the unit will start reading 0.9'. It will still show bottom contour, and read a accurate water temp, but will not show the depth right. I have checked the angle of the transducer and everything looks fine. What could be my problem??????????

How fast are you moving when you loose the bottom?

I have a Matrix 87c that has started showing irratic readings. It will jump all over the place from about 12' to 20' when I'm in 12' of water. Still shows bottom and all. Just does it near deeper water though. Everything is straight.

Transducer is mounted to trolling motor, I lose depth after a couple hours of fishing. Usually run on the #2 setting, sometimes it will go out when I'm moving, and sometimes when I'm just drifting. Seems to stuck when moving from deep water to shallower water.

Do you have another unit powered on at the console? If so, you could be getting interferance. That's about all I've got though.

Wannabe...

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Originally Posted by Wannabe...

Do you have another unit powered on at the console? If so, you could be getting interferance. That's about all I've got though.

Wannabe...

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Nope, just a simple set up. Transducer on trolling motor, powered off trolling battery, thats it.

Hmmm. Only other suggestion I'd have is to run up or down the sensitivity. When it goes crazy, can you power it down and back up and will it re-lock?

Can you switch it to your cranking batter? I doubt that's the issue though since it's intermittant.

Past that, I see a warranty claim in your future. Sorry.

Wannabe...

Reset your unit to the factory settings and start from there. You might have screwed it up trying to get it the way you wanted it. Wont hurt to start over.

I have the same problems but mine only happens in certain spots on the lake , mainly hard gravel bottom. Mine will show continuous fish at about half the depth.

Thanks for the advice guys, I did turn the sensitivity way up after reading an article about getting the most from your graph. I'll try it when I'm on the water this weekend.