Humminbird 360 screen goes dark

[carp104]

I've recently just started having an issue with an original trolling motor mount 360 unit that I've been running for years. Lately I'm noticing my screen will gradually become darker until the point it is completely unreadable. Even stranger, when I lift the trolling motor out of the water and drop it back down into the water, even if only for a second, the picture immediately becomes clear again. I don't even mean fully lifting it out of the water and stowing it, I mean just enough to get the head of the 360 out of the water and then immediately dropping it back down. However it will gradually darken again until it's unreadable. So in order to use it I have to constantly lift it out of the water and drop it back in to get a clear picture.

My only thoughts are perhaps water intrusion is mixing with the acoustic oil inside the head, and maybe the movement of raising and lowering it mixes the oil & water back up and as it begins to settle the image goes dark again. Very bizarre.

Has anyone had this problem or have any recommendations on trouble shooting it? I really need the unit the next several weekends for tournaments and would prefer not to send it in at this time.

[Wayne P.]

Water mixing with the oil is good. Still gives a solid media for the sound pulses to pass through. AIR between the SI piezos and pod will cause the blackout.
Sooo you may want to try opening it up and filling the pod with mineral oil, antifreeze, or water so there is no air to block the sonar pulses.
Water will freeze, so you may want to use one of the other two.

[carp104]

Interesting, though I'm guessing the seal is compromised if enough oil got out for it to have air in the pod.

[carp104]

Took the pod off, added mineral oil and re-assembled. Works like new!