Bow Humminbird depth reading off

[cjac]

Question for y'all on my Humminbird units and the depth reading. My bow unit (‘bird 958) depth reads depth fine until I hit the trolling motor pedal/fob for power, and then I lose my depth and it shows me in 160 feet of water or whatever. Lay off the trolling motor power and it reads fine. My trolling motor is the only thing on the front 2 deep cycles, and my 'birds are tied to the cranking battery. The unit at the console reads fine.

Weird part is all works fine until I lean on the TM for power, so that rules out a lot of pure connection/wiring problems, right? All battery connections look fine and are tight as I checked it all again last night, unless there is a ground or connection somewhere I’m missing. It was working fine earlier and I had not changed anything from when working to not working.

Have you heard of this happening? I did a couple online searches and there’s a bunch of mixed messages but nothing specific. This is on a 17 foot Lund.

Thanks, Chris

[h8go4s]

Interesting that it was working fine before and went bad suddenly for no apparent reason. Is the transducer built into the TM or separate? You might have a worn spot on the cable shielding. Have you tried disconnecting and reconnecting the transducer? Try this forum also: http://forums.sideimagingsoft.com/

[h8go4s]

Maybe this will help:

http://www.humminbird.com/FAQ.aspx?ContentId=1849

[clKiekhafer]

You didn't say how old your 958 was and not sure if that makes a difference (any changes to them). I had a similar problem with mine last year after installation, but it was a 788. After working with Humminbird and doing several things to correct it they sent me a new power cable that had a filter in the power cord. I also have a 998 which comes with a power filter when new from the factory, but the 788 did not. Try working with Humminbird and they should be able to help you, their customer service is great and the new power cord was free. Not knowing if your 958 has a filter or not it is worth a try and see if they can send you a new one.

[Mike Wallace]

+1

Just went through the same thing with mine. When you call Humminbird, they will have you try a couple things first:

1. Make sure you have the latest update.

2. Check if the fuse is blown in the trolling motor (directions on their HSOforum).

3. Is the trolling motor power coming off the starting battery or the trolling battery. If trolling battery, they will ask to rewire it off the trolling motor battery.

All of those failed for me. I did, however, learn that I was getting interference back through my on board charger. Since my bow unit is wired to my starting battery, and my starting battery is wired to the charger and the charger to the trolling batteries, I was getting interference and losing depth. When I disconnected my charging system from the trolling batteries, it went away.

With all that information I called Humminbird back and they sent me a ferrite ring for the transducer cable and a new power cord for the unit. Installed both and now no interference.

[clKiekhafer]

+1

Just went through the same thing with mine. When you call Humminbird, they will have you try a couple things first:

1. Make sure you have the latest update.

2. Check if the fuse is blown in the trolling motor (directions on their HSOforum).

3. Is the trolling motor power coming off the starting battery or the trolling battery. If trolling battery, they will ask to rewire it off the trolling motor battery.

All of those failed for me. I did, however, learn that I was getting interference back through my on board charger. Since my bow unit is wired to my starting battery, and my starting battery is wired to the charger and the charger to the trolling batteries, I was getting interference and losing depth. When I disconnected my charging system from the trolling batteries, it went away.

With all that information I called Humminbird back and they sent me a ferrite ring for the transducer cable and a new power cord for the unit. Installed both and now no interference.

X2

Yep! That's exactly what I had to do for them when I had my trouble.

[cjac]

An iron ferrite ring took care of things for me today, good info, thanks!