only this unit turned on. Starts and stops constantly. The only other thing on is the ethernet switch.

Toasted unit or transducer.

everything is less than a year old. The starting and stoping was just ever so often, today its regular

Have you updated all your units?

yes just updated them. And apparently it made it worse than it was. I just installed megalive. All units are wired direct to battery. But nothing else was on while out today. Front unit was still off and trolling motor was still off.

Is the connection to the battery secure or could one (or both) of the terminal connections be loose? The on and off sounds like intermittent disconnection. Not sure about the rest though. That’s weird.

put Huminbird in the title of your thread and Wayne P will likely chime in, he's the HB guru.

Looks like a Humminbird to me.

Thats what i thought too. but all is tight and good

If your electronics are on the starting battery, You're getting noise from the motor in the units. Otherwise you've got some kind of RFI being picked up on your power lines, or cables to your transducer. If you can explain your setup it would help us more.

Two helix 12 gen 4, mega 360, mega live , ehternet switch, 2d puck in hull all wired independently to the cranking battery

Curious, was this while the boat motor was running? If it was, I would bet you a dollar that the cranking battery is the issue. The voltage regulators which charge the battery when the motor is running do not supply a very stable dc voltage . It typically has some ripple in it. Batteries don't care about this but your electronics do. Two easy tests you can do. First, if you have a spare 12v battery from an extra car, simply bring this battery along and connect your electronics to this battery only. See if the noise is still seen. Another way, if you have a 24v or 36v trolling motor. Connect your electronics to one single battery (only) of the ones used for the TM. When your driving the boat you will have a clean source of power to the electronics. Your batteries are in series to create the (24v or 36v) power for the TM. You can simply attach your wires needed for the electronics to a single battery and it will only utilize the 12v power on that battery. Although, this is not a clean power source if you use the trolling motor and the electronics at the same time. Just throwing a separate battery in the boat to run the test is a whole lot easier if you ask me. I have a 55ah agm battery that is kind of old but will allow you to run this test if you need a spare battery for the test. It will not last long with all that on it, so it would only allow you to T/s. Lastly, if you have a decent DVM (digital volt meter) you can attach the leads to your starting battery when the engine is running, and switch it to (AC). It will tell you the amount of ripple from top/bottom of the dc voltage ripple (if you have any "in RMS"). Typically need a fluke for good readings, but it will show you if there is any ripple in the power which is being generated by the motor back to the battery. Anyhoo, instant message me if you have any specific questions. RF chokes could help, but with as many things you are running you could be drawing the starting battery down quite a bit if you fish a 12 hour day. I would encourage you to add the battery voltage to your display (on the helix) overlay, just to keep an eye on the battery voltage. I'm pretty sure the HB is set to alarm if the battery voltage gets below 11.2v so if you haven't seen this, it's not a concern. Take care, and let us know what you find out.

Forgot to mention. If your using butt connectors for splicing wires together, "Your Fired". Solder everything if you can, butt connectors are moisture prone which induces resistance (thus creating a voltage drop at the connection). A bad ground would not typically cause this, but rather a lower voltage seen at the units (somewhere in the 2+ voltage dc less range than what your battery measures). I run lithium, and my helix 12 display indicates 12.8 at the front of the boat nearly all day long, and the battery for electronics measures (13.17 to 13.3 depending on the outside temp).

If your motor is not running>>> Since you have two Helix units, and only one is doing this. Swap the locations of the two, so you will use a different power plug. If the problem does not follow the suspect helix, backtrack the cables to the power source. If the problem follows, look at the back of the helix and inspect the small holes that accept the pins (from the plug dongle that attaches to the back). Make sure no pins are broke, or nothing is in any of the gold holes the pins are connecting to).

Prosise

I didn't realize the pic was so bad. The picture is clear as it gets. No noise but the strolling starts and stops constantly. If I ask my front unit to use rear 2d sonar I every 10 seconds or so i get a 2d sonar lost signal go to local yes or no. Voltage never goes below 12.2. Yes the engine is idling.

I would isolate your electronics onto its own power source and see if that fixes it. I don’t think your graph or transducer are destroyed, I think you just need to poke around and trouble shoot. Prosise gave many great suggestions

I wouldn’t suggest going to one of your trolling motor batteries, everytime you run your trolling motor you’ll get a lot of distortion, you won’t be happy.