Help with Humminbird 788 C HD DI

I bought this new about three months ago, had it installed and can not get to work right. Contacted HB and they suggested changing the noise reduction to "high 3". Still not working...here is what the picture shows with default settings at high 3 noise reduction....any ideas?

I have not seen that but that is bad. I would send it back to HB or take it back to where you bought it. I installed my HB myself and it works beautifully. They should work right from the first time you turn it on. Maybe take the head unit to BPS and let them plug it up to their display cables and see if it works. Guys there are very helpful. I bought mine somewhere else but they answered all my questions and even said if I couldn't get settings right to bring it up there and they would set it up for me. Good guys at BPS. One guy there is an expert on HB and the other guys are Lowrance guru's. Good luck.

Something is Wrong!

It’s your sensitive – and reduce your surface clarity!

Go back to factory resets – and if that don’t work (it’s probably your transducer and if not that - it’s your unit).

RESET – that is normally IT, defaults are good – normally perfect, if not we have other problems - we need to send it back to the factory - Call or Email them (Return it),

PM me your settings and I will help out.

Good news, service staff at HB is sending a new power line with a filter and a ferrite ring for my transducer......say that aught to fix it! I will keep you posted!

That particular model has had extensive interference problems with certain trolling motors.

That pic is no bueno. I too installed my own 798 and it's works perfect.


I say punt

I had a 596c HDD that did the same thing after fooling around with hb and put their cables on and updating software I finally gave up and sold it to a friend who warned about the problem firstly still having the same issue with it but mine was on trolling motor think that had a lot to do with it good luck hope you get it worked out

Thought I would let y'all know that HB sent me a new power cable with a filter built in and a ferrite ring to wrap my transducer cable around. I installed both and relocated my transducer and everything works great! A couple of things I found when I installed the power cable....the guy that did the initial install zip tied the power and transducer cable with the other wires under the console, which I am sure created at least a little noise. Next I noticed that the transducer was about an eighth inch above the hull on the transom and the instructions say level on fiberglass and about an eighth inch below on aluminum....my boat is aluminum so I dropped it down a little. Thought I would share for two reasons...first despite your skill set consider installing on your own...no one will care as much about the outcome as you do. Also thought if you are having the same problem you may review how yours is installed.

Good stuff Barn Door!