C 120 what is going on here?

[Sea Shift]

I am new to Raymarine products and while out fishing my C120 FF acting up. The best way to describe it is that it would start to mark bait, then just cut out. See how on the picture there is a distinct cutoff line. I tried doing a DSM reset and that didn't seem to help. It did function ok at other times throughout the day but not sure what was going on. Any ideas?

 

[Fishtales]

Looks like in the pic it was on manual range on the button yet auto on the display. It appears you have it on split screen with both frequencies operating and then approached a steep shelf from 150 to approx 25 feet - is that correct? Can you run the unit on single freq full auto mode and take another screen shot?

 

[Sea Shift]

You are correct that the display is in split screen and manual. It was never put in auto in this screen and we were in over 300 ft at the time. The two lines you see in the right display are the returns from the two downriggers we had out. That is the problem, it seems to start picking something up at that 25 ft area and blacking out everything to the bottom, then something happens automatically and it STOPS and returns to what you see on the right of the screens........

 

[bhemi]

Check your voltage to the unit. I have a c80 and over time I have found that if you have a low charge or a failing battery this can happen.

 

[Sea Shift]

Well, voltage it was,.....sort of. I dug into the under deck compartments to find the DSM 300 module. Once I did, i checked the power connection, only to find that it had come loose. I tried to tighten it and no luck! the little nub on the tightening collar was broken and will not allow it to snug up. So I have ordered a new power cord and hopefully that will solve all the issues

 

[Pete1313]

My DSM 30 did similar things due to voltage problems-- and the 'NUB" on mine wasn't even broken - just a bad connection in the DSM. replaced it under warranty and now, voila...no issues.

 

[Fishtales]

They are sensitive to power spikes or noise. A few times a year my E series do not show the depth on the finder. I need to do a hard reset and since my DSM doesn't have a power switch on it, I have to set the battery switches both to off and on to recycle power.